Glimpsing through the high redshift neutral hydrogen fog
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The summer afternoon was a symphony of warmth and life. The sun hung high in the sky, casting a golden glow over everything it touched. The air was thick with humidity, a testament to the seasons relentless heat. Yet, it was this very heat that brought out the vibrancy of the world around me.The trees stood tall, their leaves a lush green that seemed to deepen under the suns embrace. The chirping of birds filled the air, their melodies echoing through the branches. The occasional rustle of leaves was the only indication of a gentle breeze that dared to challenge the stillness of the day.Children played outside, their laughter a joyful counterpoint to the lazy hum of the afternoon. The sound of splashing water from a nearby pool or sprinkler was a welcome relief, a reminder of the simple pleasures that summer offered.The scent of freshly cut grass wafted through the air, mingling with the sweet fragrance of blooming flowers. Roses, daisies, and hydrangeas stood proudly in gardens, their colors a brilliant contrast to the greenery that surrounded them.As the afternoon wore on, the heat began to wane, making way for the cool embrace of evening. The sky slowly transitioned from a bright blue to a soft orange, signaling the impending sunset. The world seemed to pause, holding its breath in anticipation of the days grand finale.And then, as if on cue, the sun began to set. The sky was painted with hues of pink, orange, and purple, a canvas of breathtaking beauty. The sun dipped lower and lower, until it finally disappeared below the horizon, leaving behind a sky filled with stars.The summer afternoon, with its warmth, its life, and its beauty, was a reminder of the simple joys that nature had to offer. It was a time to appreciate the world around us, to revel in the beauty of a season that, while hot, was also filled with life and vibrancy.。
The Ones Who Walk Away From OmelasWith a clamor of bells that set the swallows soaring, the Festival of Summer came to the city Omelas, bright-towered by the sea. The rigging of the boats in harbor sparkled with flags. In the streets between houses with red roofs and painted walls, between old moss-grown gardens and under avenues of trees, past great parks and public buildings, processions moved. Some were decorous: old people in long stiff robes of mauve and grey, grave master workmen, quiet, merry women carrying their babies and chatting as they walked. In other streets the music beat faster, a shimmering of gong and tambourine, and the people went dancing, the procession was a dance. Children dodged in and out, their high calls rising like the swallows’ crossing flights over the music and the singing. All the processions wound towards the north side of the city, where on the great water-meadow called the Green Fields boys and girls, naked in the bright air, with mud-stained feet and ankles and long, lithe arms, exercised their restive horses before the race. The horses wore no gear at all but a halter without bit. Their manes were braided with streamers of silver, gold, and green. They flared their nostrils and pranced and boasted to one another; they were vastly excited, the horse being the only animal who has adopted our ceremonies as his own. Far off to the north and west the mountains stood up half encircling Omelas on her bay. The air of morning was so clear that the snow still crowning the Eighteen Peaks burned with white-gold fire across the miles of sunlit air, under the dark blue of the sky. There was just enough wind to make the banners that marked the racecourse snap and flutter now and then. In the silence of the broad green meadows one could hear the music winding through the city streets, farther and nearer and ever approaching, a cheerful faint sweetness of the air that from time to time trembled and gathered together and broke out into the great joyous clanging of the bells.Joyous! How is one to tell about joy? How describe the citizens of Omelas?They were not simple folk, you see, though they were happy. But we do not say the words of cheer much any more. All smiles have become archaic. Given a description such as this one tends to make certain assumptions. Given a description such as this one tends to look next for the King, mounted on a splendid stallion and surrounded by his noble knights, or perhaps in a golden litter borne by great-muscled slaves. But there was no king. They did not use swords, or keep slaves. They were not barbarians.I do not know the rules and laws of their society, but I suspect that they were singularly few. As they did without monarchy and slavery, so they also got on without the stock exchange, the advertisement, the secret police, and the bomb. Yet I repeat that these were not simple folk, not dulcet shepherds, noble savages, bland utopians. They were not less complex than us. The trouble is that we have a bad habit, encouraged by pedants and sophisticates, of considering happiness as something rather stupid. Only pain is intellectual, only evil interesting. This is the treason of the artist: a refusal to admit the banality of evil and the terrible boredom of pain. If you can’t lick ‘em, join ‘em. If it hurts, repeat it. But to praise despair is to c ondemn delight, to embrace violence is to lose hold of everything else. We have almost lost hold; we can no longer describe a happy man, nor make any celebration of joy. Howcan I tell you about the people of Omelas? They were not naive and happy children—though their children were, in fact, happy. They were mature, intelligent, passionate adults whose lives were not wretched. O miracle! but I wish I could describe it better.I wish I could convince you. Omelas sounds in my words like a city in a fairy tale, long ago and far away, once upon a time. Perhaps it would be best if you imagined it as your own fancy bids, assuming it will rise to the occasion, for certainly I cannot suit you all. For instance, how about technology? I think that there would be no cars or helicopters in and above the streets; this follows from the fact that the people of Omelas are happy people. Happiness is based on a just discrimination of what is necessary, what is neither necessary nor destructive, and what is destructive. In the middle category, however—that of the unnecessary but undestructive, that of comfort, luxury, exuberance, etc.—they could perfectly well have central heating, subway trains, washing machines, and all kinds of marvelous devices not yet invented here, floating light-sources, fuelless power, a cure for the common cold. Or they could have none of that; it doesn’t matter.The Ones Who Walk Away From OmelasWith a clamor of bells that set the swallows soaring, the Festival of Summer came to the city Omelas, bright-towered by the sea. The rigging of the boats in harbor sparkled with flags. In the streets between houses with red roofs and painted walls, between old moss-grown gardens and under avenues of trees, past great parks and public buildings, processions moved. Some were decorous: old people in long stiff robes of mauve and grey, grave master workmen, quiet, merry women carrying their babies and chatting as they walked. In other streets the music beat faster, a shimmering of gong and tambourine, and the people went dancing, the procession was a dance. Children dodged in and out, their high calls rising like the swallows’ crossing flights over the music and the singing. All the processions wound towards the north side of the city, where on the great water-meadow called the Green Fields boys and girls, naked in the bright air, with mud-stained feet and ankles and long, lithe arms, exercised their restive horses before the race. The horses wore no gear at all but a halter without bit. Their manes were braided with streamers of silver, gold, and green. They flared their nostrils and pranced and boasted to one another; they were vastly excited, the horse being the only animal who has adopted our ceremonies as his own. Far off to the north and west the mountains stood up half encircling Omelas on her bay. The air of morning was so clear that the snow still crowning the Eighteen Peaks burned with white-gold fire across the miles of sunlit air, under the dark blue of the sky. There was just enough wind to make the banners that marked the racecourse snap and flutter now and then. In the silence of the broad green meadows one could hear the music winding through the city streets, farther and nearer and ever approaching, a cheerful faint sweetness of the air that from time to time trembled and gathered together and broke out into the great joyous clanging of the bells.Joyous! How is one to tell about joy? How describe the citizens of Omelas?They were not simple folk, you see, though they were happy. But we do not say the words of cheer much any more. All smiles have become archaic. Given a descriptionsuch as this one tends to make certain assumptions. Given a description such as this one tends to look next for the King, mounted on a splendid stallion and surrounded by his noble knights, or perhaps in a golden litter borne by great-muscled slaves. But there was no king. They did not use swords, or keep slaves. They were not barbarians.I do not know the rules and laws of their society, but I suspect that they were singularly few. As they did without monarchy and slavery, so they also got on without the stock exchange, the advertisement, the secret police, and the bomb. Yet I repeat that these were not simple folk, not dulcet shepherds, noble savages, bland utopians. They were not less complex than us. The trouble is that we have a bad habit, encouraged by pedants and sophisticates, of considering happiness as something rather stupid. Only pain is intellectual, only evil interesting. This is the treason of the artist: a refusal to admit the banality of evil and the terrible boredom of pain. If you can’t lick ‘em, join ‘em. If it hurts, repeat it. But to praise despair is to condemn delight, to embrace violence is to lose hold of everything else. We have almost lost hold; we can no longer describe a happy man, nor make any celebration of joy. How can I tell you about the people of Omelas? They were not naive and happy children—though their children were, in fact, happy. They were mature, intelligent, passionate adults whose lives were not wretched. O miracle! but I wish I could describe it better.I wish I could convince you. Omelas sounds in my words like a city in a fairy tale, long ago and far away, once upon a time. Perhaps it would be best if you imagined it as your own fancy bids, assuming it will rise to the occasion, for certainly I cannot suit you all. For instance, how about technology? I think that there would be no cars or helicopters in and above the streets; this follows from the fact that the people of Omelas are happy people. Happiness is based on a just discrimination of what is necessary, what is neither necessary nor destructive, and what is destructive. In the middle category, however—that of the unnecessary but undestructive, that of comfort, luxury, exuberance, etc.—they could perfectly well have central heating, subway trains, washing machines, and all kinds of marvelous devices not yet invented here, floating light-sources, fuelless power, a cure for the common cold. Or they could have none of that; it doesn’t mat ter.As you like it. I incline to think that people from towns up and down the coast have been coming in to Omelas during the last days before the Festival on very fast little trains and double-decked trams, and that the train station of Omelas is actually the handsomest building in town, though plainer than the magnificent Farmers’ Market. But even granted trains, I fear that Omelas so far strikes some of you as goody-goody. Smiles, bells, parades, horses, bleh. If so, please add an orgy. If an orgy would help, don’t hesitate. Let us not, however, have temples from which issue beautiful nude priests and priestesses already half in ecstasy and ready to copulate with any man or woman, lover or stranger, who desires union with the deep godhead of the blood, although that was my first idea. But really it would be better not to have any temples in Omelas—at least, not manned temples. Religion yes, clergy no. Surely the beautiful nudes can just wander about, offering themselves like divine souffles to the hunger of the needy and the rapture of the flesh. Let them join the processions. Let tambourines be struck above the copulations, and the glory of desire be proclaimed upon the gongs,and (a not unimportant point) let the offspring of these delightful rituals be beloved and looked after by all. One thing I know there is none of in Omelas is guilt. But what else should there be? I thought at first there were not drugs, but that is puritanical. For those who like it, the faint insistent sweetness of drooz may perfume the ways of the city, drooz which first brings a great lightness and brilliance to the mind and limbs, and then after some hours a dreamy languor, and wonderful visions at last of the very arcana and inmost secrets of the Universe, as well as exciting the pleasure of sex beyond belief; and it is not habit-forming. For more modest tastes I think there ought to be beer. What else, what else belongs in the joyous city? The sense of victory, surely, the celebration of courage. But as we did without clergy, let us do without soldiers. The joy built upon successful slaughter is not the right kind of joy; it will not do; it is fearful and it is trivial. A boundless and generous contentment, a magnanimous triumph felt not against some outer enemy but in communion with the finest and fairest in the souls of all men everywhere and the splendor of the world’s summer: this is what swells the hearts of the people of Omelas, and the victory they celebrate is that of life. I really don’t think many of them need to take dro oz.Most of the procession have reached the Green Fields by now. A marvelous smell of cooking goes forth from the red and blue tents of the provisioners. The faces of small children are amiably sticky; in the benign grey beard of a man a couple of crumbs of rich pastry are entangled. The youths and girls have mounted their horses and are beginning to group around the starting line of the course. An old women, small, fat, and laughing, is passing out flowers from a basket, and tall young men where her flowers in their shining hair. A child of nine or ten sits at the edge of the crowd, alone, playing on a wooden flute. People pause to listen, and they smile, but they do not speak to him, for he never ceases playing and never sees them, his dark eyes wholly rapt in the sweet, thin magic of the tune.He finishes, and slowly lowers his hands holding the wooden flute.As if that little private silence were the signal, all at once a trumpet sounds from the pavilion near the starting line: imperious, melancholy, piercing. The horses rear on their slender legs, and some of them neigh in answer. Sober-faced, the young riders stroke the horses’ necks and soothe them, whispering, “Quiet, quiet, there my beauty, my hope....” They begin to form in rank along the starting li ne. The crowds along the racecourse are like a field of grass and flowers in the wind. The Festival of Summer has begun.Do you believe? Do you accept the festival, the city, the joy? No? Then let me describe one more thing.In a basement under one of the beautiful public buildings of Omelas, or perhaps in the cellar of one of its spacious private homes, there is a room. It has one locked door, and no window. A little light seeps in dustily between cracks in the boards, secondhand from a cobwebbed window somewhere across the cellar. In one corner of the little room a couple of mops, with stiff, clotted, foul-smelling heads stand near a rusty bucket. The floor is dirt, a little damp to the touch, as cellar dirt usually is. The room is about three paces long and two wide: a mere broom closet or disused tool room. In the room a child is sitting. It could be a boy or a girl. It looks about six, butactually is nearly ten. It is feeble-minded. Perhaps it was born defective, or perhaps it has become imbecile through fear, malnutrition, and neglect. It picks its nose and occasionally fumbles vaguely with its toes or genitals, as it sits hunched in the corner farthest from the bucket and the two mops. It is afraid of the mops. It finds them horrible. It shuts its eyes, but it knows the mops are still standing there; and the door is locked; and nobody will come. The door is always locked; and nobody ever comes, except that sometimes—the child has no understanding of time or interval—sometimes the door rattles terribly and opens, and a person, or several people, are there. One of them may come in and kick the child to make it stand up. The others never come close, but peer in at it with frightened, disgusted eyes. The food bowl and the water jug are hastily filled, the door is locked, the eyes disappear. The people at the door never say anything, but the child, who has not always lived in the tool room, and can remember sunlight and its mother’s voice, sometimes speaks. “I will be good,” it says. “Please let me out. I will be good!” They never answer. The child used to scream for help at night, and cry a good deal, but now it only makes a kind of whining, “eh-haa, eh-haa,” and it speaks less and less often. It is so thin there are no calves to its legs; its belly protrudes; it lives on a half-bowl of corn meal and grease a day. It is naked. Its buttocks and thighs are a mass of festered sores, as it sits in its own excrement continually.They all know it is there, all the people of Omelas. Some of them have come to see it, others are content merely to know it is there. They all know that it has to be there. Some of them understand why, and some do not, but they all understand that their happiness, the beauty of their city, the tenderness of their friendships, the health of their children, the wisdom of their scholars, the skill of their makers, even the abundance of their harvest and the kindly weathers of their skies, depend wholly on this child’s abominable misery.This is usually explained to children when they are between eight and twelve, whenever they seem capable of understanding; and most of those who come to see the child are young people, though often enough an adult comes, or comes back, to see the child. No matter how well the matter has been explained to them, these young spectators are always shocked and sickened at the sight. They feel disgust, which they had thought themselves superior to. They feel anger, outrage, impotence, despite all the explanations. They would like to do something for the child. But there is nothing they can do. If the child were brought up into the sunlight out of that vile place, if it were cleaned and fed and comforted, that would be a good thing indeed; but if it were done, in that day and hour all the prosperity and beauty and delight of Omelas would wither and be destroyed. Those are the terms. To exchange all the goodness and grace of every life in Omelas for that single, small improvement: to throw away the happiness of thousands for the chance of the happiness of one: that would be to let guilt within the walls indeed.The terms are strict and absolute; there may not even be a kind word spoken to the child.Often the young people go home in tears, or in a tearless rage, when they have seen the child and faced this terrible paradox. They may brood over it for weeks or years.But as time goes on they begin to realize that even if the child could be released, it would not get much good of its freedom: a little vague pleasure of warmth and food, no doubt, but little more. It is too degraded and imbecile to know any real joy. It has been afraid too long ever to be free of fear. Its habits are too uncouth for it to respond to humane treatment. Indeed, after so long it would probably be wretched without walls about it to protect it, and darkness for its eyes, and its own excrement to sit in. Their tears at the bitter injustice dry when they begin to perceive the terrible justice of reality, and to accept it. Yet it is their tears and anger, the trying of their generosity and the acceptance of their helplessness, which are perhaps the true source of the splendor of their lives. Theirs is no vapid, irresponsible happiness. They know that they, like the child, are not free. They know compassion. It is the existence of the child, and their knowledge of its existence, that makes possible the nobility of their architecture, the poignancy of their music, the profundity of their science. It is because of the child that they are so gentle with children. They know that if the wretched one were not there sniveling in the dark, the other one, the flute-player, could make no joyful music as the young riders line up in their beauty for the race in the sunlight of the first morning of summer.Now do you believe in them? Are they not more credible? But there is one more thing to tell, and this is quite incredible.At times one of the adolescent girls or boys who go to see the child does not go home to weep or rage, does not, in fact, go home at all. Sometimes also a man or woman much older falls silent for a day or two, and then leaves home. These people go out into the street, and walk down the street alone. They keep walking, and walk straight out of the city of Omelas, through the beautiful gates. They keep walking across the farmlands of Omelas. Each one goes alone, youth or girl, man or woman. Night falls; the traveler must pass down village streets, between the houses with yellow-lit windows, and on out into the darkness of the fields. Each alone, they go west or north, towards the mountains. They go on. They leave Omelas, they walk ahead into the darkness, and they do not come back. The place they go towards is a place even less imaginable to most of us than the city of happiness. I cannot describe it at all. It is possible that it does not exist. But they seem to know where they are going, the ones who walk away from Omelas.随着一阵响彻云霄的钟声的敲响,一群燕子惊得展翅高翔,白塔映日的海滨城市奥米勒斯迎来了她的夏庆节。
夜的第七章英文版The night was quiet, with only the sound of crickets chirping in the distance. The moon cast a soft glow over the landscape, illuminating the trees and casting long shadows on the ground. In the distance, a lone wolf howled, its mournful cry echoing through the night.As I walked through the darkened forest, the cool night air sent a shiver down my spine. The trees loomed overhead, their branches swaying gently in the breeze. I could hear the rustling of leaves and the occasional hoot of an owl as I made my way deeper into the woods.Suddenly, a flash of movement caught my eye. I froze, my heart pounding in my chest. Was it just a trick of the light, or was there something out there in the darkness with me? I strained my eyes, trying to make out any shapes in the shadows.And then I saw it. A pair of glowing eyes, staring back at me from the darkness. My breath caught in my throat as I realized I was not alone. The creature stepped forward, revealing itself to be a majestic stag, its antlers gleaming in the moonlight.I stood there, transfixed by the beauty of the creature before me. It seemed to radiatea sense of calm and peace, despite the wildness of the night around us. The stag regarded me with a steady gaze, as if assessing whether I posed a threat.Slowly, I reached out a hand towards the stag, my fingers trembling slightly. To my surprise, the creature did not shy away. It allowed me to stroke its soft fur, a gesture of trust and acceptance. In that moment, I felt a deep connection to the natural world around me.As the night wore on, the stag stayed by my side, leading me through the forest with a silent grace. We walked together in companionable silence, the only sound the crunch of leaves beneath our feet. I felt a sense of peace and contentment wash over me, knowing that I was not alone in the darkness.Eventually, we emerged from the forest, the first light of dawn breaking over the horizon. The stag turned to me, its eyes meeting mine for a brief moment before it vanished into the trees. I stood there, watching as the sun rose higher in the sky, feeling grateful for the experience I had shared with the creature of the night.And as I made my way back home, the memory of that encounter stayed with me, a reminder of the magic and mystery that lurked in the darkness. The night may be full of unknown dangers, but it is also a place of wonder and beauty, where unexpected connections can be forged. And I knew that I would always cherish the memory of the night I walked with the stag.。
155文|张丽娟《荷塘月色》译作赏析——基于图形——背景理论一、图形——背景理论图形—背景理论源于由丹麦心理学家Rubin (1915)首先提出来的图形背景分离的观点(figure-ground segregation),其后这一理论被完形心理学借鉴,进行人类的知觉研究。
该理论认为图形和背景这两个部分构成人们的知觉场。
我们通常把某一认知概念或感知中突出的部分称为图形,由于它具有高度清晰的结构,因此是人们易关注的部分;而相对地,背景则是为突出图形而起衬托作用的部分,是图形的认知参照点,往往细节模糊未分化,因此也不易为人们所注意,容易被忽略。
而人们在观看某一客体时,总是在细节模糊未分化的背景中看到清晰突出的图形。
对这一理论可以根据著名的人面/花瓶图来理解:当我们把白色当成背景,呈现出来的就是一个黑色的花瓶图形;而反过来把黑色当成背景的话,那么呈现出来的就是两个人脸在对视的侧面。
而在一般情况下,正常人是没有办法同时看到脸和花瓶,这是因为人们对信息的认知是需要通过图形和背景之间的转换来完成的。
图形—背景理论中的一个核心概念就是突显原则,当我们观察身边的物体时,下意识就把物体周围的环境作为背景,作为参照物,而把这个物体独立出来,凸显出来。
也就是说突显原则是用一个物体或概念作为认知参照物去说明另一个物体或概念。
由于背景具有已知的空间或时间特征,但是图形却没有,所以背景就能够充当参照点的角色,用来描写、确定图形的未知特征(文旭,2003)。
图形和背景作为一种视觉空间概念,在语言的各个层面都有普遍的体现,但是语言中的图形和背景与视觉场中的图形和背景并不是一致的,是有差别的,因为视觉场中的图形和背景往是具体的,而语言中的图形和背景则相对比较抽象。
二、图形——背景理论与朱纯深英译版《荷塘月色》郝霞(2012)认为翻译与图形—背景理论非常相似,因此有着非常密切的关系。
她就两者之间的相似性作出了以下阐述:第一,翻译与图形—背景理论都是认知的;第二,两者都与意义相关;第三,翻译中也涉及到图形背景理论的主要概念,参照及对比;第四,翻译的过程与图形背景感知的过程也非常相似。
高级英语第三版lesson7课文翻译布里尔小姐Lesson Seven Miss Brill尽管阳光明媚——蓝天涂上了金色,巨大的光点犹如泼洒在公共花园里的白葡萄酒——布里尔小姐很高兴自己还是决定戴上了狐皮围巾。
Although it was so brilliantly fine – the blue sky powdered with gold and the great spots of light like white wine splashed over the Jardins Publiques – Miss Brill was glad that she had decided on her fur.空气中一丝风也没有,但当你张开嘴时,却有那么一丝丝凉意。
那感觉犹如你要吸一小口冰水时从杯子里冒出的凉气那样。
不时有一片落叶从无人知晓的地方飘来,从天空飘来。
The air was motionless, but when you opened your mouth there was just a faint chill, like a chill from a glass of iced water before you sip, and now and again a leaf came drifting – from nowhere, from the sky.布里尔小姐抬起手来摸着狐皮围巾。
Miss Brill put up her hand and touched her fur.可爱的小东西!再次触摸到它感觉真好。
Dear little thing! I t was nice to feel it again.下午她把它从盒子里拿了出来,抖掉防蛀粉,好好地刷了一遍,把没有光泽的小眼睛擦得又恢复了生气。
She had taken it out of its box that afternoon, shaken out the moth-powder, given it a good brush, and rubbed the life back into the dim little eyes.“我怎么了?”忧伤的小眼睛问道。
A MIDSUMMER NOON IN THE AUSTRALIAN FOREST By Charles HarpurNot a bird disturbs the air!There is quiet everywhere;Over plains and over woodsWhat a mighty stillness broods.Even the grasshoppers keep[All the birds and insects keep]Where the coolest shadows sleep;Even the busy ants are foundResting in their pebbled mound;Even the locust clingeth nowIn silence to the barky bough:And over hills and over plainsQuiet, vast and slumbrous, reigns.Only there's a drowsy hummingFrom yon warm lagoon slow coming:'Tis the dragon-hornet - see!All bedaubed resplendentlyWith yellow on a tawny ground -Each rich spot nor square nor round,But rudely heart-shaped, as it wereThe blurred and hasty impress there,Of vermeil-crusted sealDusted o'er with golden meal:Only there's a droning whereYon bright beetle gleams the air -Gleams it in its droning flight[Tracks it in its gleaming flight]With a slanting track of light,Till rising in the sunshine higher,[Rising in the sunshine higher,]Its shards flame out like gems on fire.[Till its shards flame out like fire.]Every other thing is still,Save the ever wakeful rill,Whose cool murmur only throwsA cooler comfort round Repose;Or some ripple in the seaOf leafy boughs, where, lazily,Tired Summer, in her forest bowerTurning with the noontide hour,Heaves a slumbrous breath, ere sheOnce more slumbers peacefully.0 'tis easeful here to lieHidden from Noon's scorching eye,In this grassy cool recessMusing thus of Quietness.two versions of this poem have been located. The relevant changes are included in the text in square brackets, i.e. "[...]".A Storm in the MountainsBy Charles HarpurA lonely boy, far venturing from homeOut on the half-wild her d’s faint tracks I roam;Mid rock-browned mountains, which with stony frownGlare into haggard chasms deep adown;A rude and craggy world, the prospect liesBounded in circuit by the bending skies.Now at some clear pool scooped out by the shocksOf rain-floods plunging from the upper rocksWhose liquid disc in its undimpled restGlows like a mighty gem brooching the mountain’s breast,I drink and must, or mark the wide-spread herd,Or list the thinking of the dingle-bird;And now towards some wild-hanging shade I stray,To shun the bright oppression of the day;For round each crag, and o’er each bosky swell,The fierce refracted heat flares visible,Lambently restless, like the dazzling hemOf some else viewless veil held trembling over them.Why congregate the swallows in the air,And northward then in rapid flight repair?With sudden swelling din, remote yet harsh,Why roar the bull-frogs in the tea-tree marsh?Why cease the locusts to throng up in flightAnd clap their gay wings in the fervent light?Why climb they, bodingly demure, insteadThe tallest spear-grass to the bending head?Instinctively, along the sultry sky,I turn a listless, yet inquiring, eye;And mark that now with a slow gradual paceA solemn trance creams nort hward o’er its face; Yon clouds that late were labouring past the sun, Reached by its sure arrest, one after one,Come to a heavy halt; the airs that playedAbout the rugged mountains all are laid:While drawing nearer far-off heights appear,As in a dream’s wild prospect, strangely near!Till into wood resolves their robe of blue,And the grey crags rise bluffly on the view. Such are the signs and tokens that presageA summer hurricane’s forthcoming rage.At length the south sends out her cloudy heaps And up the glens at noontide dimness creeps; The birds, late warbling in the hanging greenOff steep-set brakes, seek now some safer screen; The herd, in doubt, no longer wanders wide,But fast ingathering throngs yon mountain’s side, Whose echoes, surging to its tramp, might seem The muttered troubles of some Titan’s dream.Fast the dim legions of the muttering storm Throng denser, or protruding columns form; While splashing forward from their cloudy lair, Convolving flames, like scouting dragons, glare: Low thunders follow, labouring up the sky;And as fore-running blasts go blaring by,At once the forest, with a mighty stir,Bows, as in homage to the thunderer!Hark! From the dingoes blood-polluted densIn the gloom-hidden chasms of the glens,Long fitful howls wail up; and in the blast Strange hissing whispers seem to huddle past; As if the dread stir had aroused from sleep Weird spirits, cloistered in yon cavy steep(On which, in the grim past, some Cain’s offence Hath haply outraged heaven!) Who rising thence Wrapped in the boding vapours, laughed again To wanton in the wild-willed hurricane.See in the storm’s front, sailing dark and dread,A wide-winged eagle like a black flag spread!The clouds aloft flash doom! Short stops his flight!He seems to shrivel in the blasting light!The air is shattered with a crashing sound,And he falls stonelike, lifeless, to the ground.Now, like a shadow at great nature’s heart,The turmoil grows. Now wonder, with a start,Marks where right overhead the storm careers,Girt with black horrors and wide-flaming fears!Arriving thunders, mustering on his path,Swell more and more the roarings of his wrath,As out in widening circles they extend,And then—at once—in utter silence end.Portentous silence! Time keeps breathing past,Yet it continues! May this marvel last?This wild weird silence in the midst of gloomSo manifestly big with coming doom?Tingles the boding ear; and up the glensInstinctive dread comes howling from the wild-dogs dens.Terrific vision! Heaven’s great ceiling splits,And a vast globe of writhing fire emits,Which pouring down in one continuous stream,Spans the black concave like a burning beam,A moment;—then from end to end it shakesWith a quick motion—and in thunder breaks!Peal rolled on peal! While heralding the sound,As each concussion thrills the solid ground,Fierce glares coil, snake-like, round the rocky wensOf the red hills, or hiss into the glens,Or thick through heaven like flaming falchions swarm, Cleaving the teeming cisterns of the storm,From which rain-torrents, searching every gash,Split by the blast come sheeting with a dash.On yon grey peak, from rock-encrusted roots,The mighty patriarch of the wood upshoots,In whose proud-spreading top’s imperial height,The mountain-eagle loveth most to light:Now dimly seen through the tempestuous air,His form seems harrowed by a mad despair,As with his ponderous arms uplifted high,He wrestles with the storm and threshes at the sky!A swift bolt hurtles through the lurid air,Another thundering crash! The peak is bare!Huge hurrying fragments all around are cast,The wild-winged, mad-limbed monsters of the blast.The darkness thickens! With despairing cryFrom shattering boughs the rain-drenched parrtos fly; Loose rocks roll rumbling from the mountains round, And half the forest strews the smoking ground;To the bared crags the blasts now wilder moan,And the caves labour with a ghostlier groan.Wide raging torrents down the gorges flowSwift bearing with them to the vale belowThose sylvan wrecks that littered late the pathOf the loud hurricane s all-trampling wrath.The storm is past. Yet booming on afarIs heard the rattling of the thunder-car,And that low muffled moaning, as of grief,Which follows with a wood-sigh wide and brief.The clouds break up; the sun s forth-bursting rays Clothe the wet landscape with a dazzling blaze;The birds begin to sing a lively strain,And merry ec hoes ring it o’er again;The clustered herd is spreading out to graze,Though lessening torrents still a hundred waysFlash downward, and from many a rock ledgeA mantling gush comes quick and shining o er the edge.’Tis evening; and the torrent’s fu rious flowRuns gentlier now into the lake below,O’er all the freshened scene no sound is heard,Save the short twitter of some busied bird,Or a faint rustle made amongst the treesBy wasting fragments of a broken breeze.Along the wild and wreck-strewed paths I wind, Watching earth’s happiness with quiet mind,And see a beauty all unmarked till nowFlushing each flowery nook and sunny brow;Wished peace returning like a bird of calm,Brings to the wounded world its blessed healing balm.On nerveless, tuneless lines how sadlyRinging rhymes may wasted be,While blank verse oft is mere prose madlyStriving to be poetry:While prose that’s craggy as a mountainMay Apollo’s sun-robe don,Or hold the well-spring of a fountainBright as that in Helicon.Bell BirdsHenry KendallBy channels of coolness the echoes are calling,And down the dim gorges I hear the creek falling;It lives in the mountain, where moss ad the sedges Touch with their beauty the banks and the ledges: Through breaks of the cedar and sycamore bowers Struggles the light that is love to the flowers,And softer than slumber, and sweeter than singing, The notes of the bell-birds are running and ringing.The silver voiced bell-birds, the darlings of day-time, They sing in September their songs of the May-time. When shadows wax strong, and the thunder bolts hurtle, They hide with their fear in the leaves of the myrtle; When rain and the sunbeams shine mingled together, They start up like fairies that follow fair weather,And straightway the hues of the feathers unfoldenAnd the green and the purple, the blue and the golden.October, the maiden of bright yellow tresses,Loiters for love in these cool windernesses,Loiters knee-deep in the grasses to listen,Where dripping rocks gleam and the leafy pools glisten. Then is the time when the water-moons splendid Break with their gold, and are scattered or blended Over the creeks, till the woodlands have warningOf songs of the bell-bird and wings of the morning.Welcome as waters, unkissed by the summersAre the voices of bell-birds to thirsty far-comers. When fiery December sets foot in the forest,And the need of the wayfarer presses the sorest,Pent in the ridges for ever and ever,The bell-birds, direct him to spring and to river,With ring and with ripple, like runnels whose torrents Are turned by the pebbles and leaves in the currents.Often I sit looking back to a childhoodMixt with the sights and the sounds of the wildwood, Longing for power and the sweetness to fashion Lyrics with beats like the heart-beats of passion -- Songs interwoven of lights and of laughters Borrowed from bell-birds in far forest rafters;So I might keep in the city and alleysThe beauty and strengths of the deep mountain valleys, Charming to slumber the pain of my lossesWith glimpses of creeks and a vision of mosses.September in AustraliaBy Henry KendallGrey winter hath gone, like a wearisime guest,And, behold, for repayment,September comes in with the wind of the WestAnd the spring in her raiment!The ways of the frost have been filled of the flowers, While the forest discoversWild wings, with the halo of hyaline hoursAnd the music of lovers.September, the maid with the swift, silver feet!She glides, and she gracesThe valleys of coolness, the slopes of the heat,With her blossomy traces;Sweet month, with a mouth that is made of a rose, She lightens and lingersIn spots where the harp of the evening glows, Attuned by her fingers.The stream from it's home in the hollow hill slipsIn a darling old fashion;And the day goeth down with a song on its lips whose key-note is passion;Far out in the fierce, bitter front of the seaI stand, and rememberDead things that were brothers and sisters of thee, Resplendent September.The West, when it blows at the fall of the noonAnd beats on the beaches,Is filled with tender and tremulous tuneThat touches and teaches;The stories of youth, of the burden of time,And the death of devotion,Come back with the wind, and are themes of the rhyme In the waves of the ocean.We, having a secret to others unknown,In the cool mountain-mosses,May whisper together, September, aloneOf our loves and our loses.One word for her beauty, and one for the graceShe gave to the hours;And then we may kiss her, and suffer her faceto sleep with the flowers.Oh, season of changes - of shadow and shine - September the splendid!My song hath no music to mingle with thine,And its burden is ended;But thou, being born of the winds and the sun,By mountain, by river,Mayst lighten and listen, and loiter and run,With thy voices for ever.。
第一课 Face to face with Hurricane Camille1.We re elevated23feet.We’re23feet above sea level.2.The place has been here since1915,and no hurricane has bothered it.The house has been here since1915,andno hurricane has ever caused any damage to it.3.We can batten down and ride it out.We can make the necessary preparations and survive the hurricane without much damage.4.The generator was doused,and the lights went out.Water got into the generator and put it out.It stopped producing electricity,so the lights also went out.5.Everybody out the back door to the cars!Everybody goes out through the back door and runs to the cars!6.The electrical systems had been killed by water.The electrical systems in the car(the battery for the starter) had been put out by water.7.John watched the water lap at the steps,and felt a crushing guilt.As John watched the water inch its way up the steps,he felt a strong sense of guilt because he blamed himself forendangering the whole family by deciding not to flee inland.8.Get us through this mess,will you?Oh God,please help us to get through this storm safely9.She carried on alone for a few bars;then her voice trailed away.Grandmother Koshak sang a few words alone and then her voice gradually grew dimmer and finally stopped.10.Janis had just one delayed reaction.Janis displayed the fear caused by the hurricane rather late.第二课 Hiroshima-the “Liveliest” City in Japan 1.Serious-looking men spoke to one another as if they were oblivious of the crowds about them…They were so absorbed in their conversation that they seemed not to pay any attention to the people around them.2.At last this intermezzo came to an end,and I found myself in front of the gigantic City Hall.At last the taxi trip came to an end and I suddenly found that I was in front of the gigantic City Hall.3.The rather arresting spectacle of little old Japan adrift amid beige concrete skyscrapers is the very symbol of the incessant struggle between the kimono and the miniskirt. The traditional floating houses among high modern buildings represent the constant struggle between old tradition and new development.4.…experiencing a twinge of embarrassment at the prospect of meeting the mayor of Hiroshima in my socks.I suffered from a strong feeling of shame when I thought of the scene of meeting the mayor of Hiroshima wearing my socks only.5.The few Americans and Germans seemed just as inhibited asI was.The few Americans and Germans seemed just as restrained as I was6.After three days in Japan,the spinal column becomes extraordinarily flexible.After three days in Japan one gets quite used to bowing to people as a ritual to show gratitude.7.I was about to make my little bow of assent,when the meaning of these last words sank in,jolting me out of my sad reverie.I was about to show my agreement by nodding when I sudd enly realized what the meaning ofhis words.His words shocked me out my sad dreamy thinking.8....and nurses walked by carrying nickel-plated instruments,t he very sight of which would send shivers down the spine of any healthy visitor....and nurses walked by carrying surgical instruments whic h were nickel plated and even healthy visitors when they see t hose instruments could not help shivering.9.Because,thanks to it,I have the opportunity to improve my character.I have the chance to raise my moral standard thanks to the il lness.第三课 Blackmail1.The words spat forth with sudden savagery,all pretense of b landness gone.Ogilvie said these words suddenly and rudely,throwing awa y his pretended politeness.2.When they find who done that last night,who killed that kid an‘its mother,then high-tailed it,they’ll throw the book,an d never mind who it hits,or whether they got fancy titles nei ther.When they find who killed the mother and the kid and t hen ran away,they'll carry out the maximum punishment no matter who will be punished in this case or what their social position is.3.The Duchess of Croydon-three centuries and a half of inbredarrogance behind her-did not yield easily.The Duchess was supported by her arrogance coming from p arents of noble familieswith a history of three centuries anda half.She wouldn’t give up easily.4.Even the self-assurance of Ogilvie flickered for an instant. The Duchess appeared so firm about their innocence thatOgilvie felt unsure if his assumption for a moment.But the mo ment was very short.5.The house detective took his time,leisurely puffing a cloud of blue cigar smoke,his eyes sardonically on the Duchess as if challenging her objection.The house detective was took his time smoking his cigar and puffed a cloud of blue smoke leisurely.At the same time,his eyes were fixed on the Duchess with contempt as if he was o penly daring her objection as she has done earlier.6.There ain’t much,out of the way,which people who stay in t his hotel do,I don’t get to hear about.No matter who stays in this hotel does anythingimproper,I a lways get to know about it.7.The Duchess of Croydon kept firm,tight rein on her racing m ind.The Duchess of Croydon is thinking quickly,but at the same t ime keeping her thoughts under control.8.And when they stopped for petrol,as they would have to,th eir speech and manner would betray them,making them co nspicuous.Furthermore,when they had to stopfor petrol,their speech and manner would make them noticeable and reveal their id entity.9)I know you are from the South.Your accent has betrayed you.10)We have no alternative in this matter.第四课 The Trial That Rocked the World1.”Don’t worry,son,we’ll show them a few tricks.”Don’t worry,young man.We have some clever and unexp ected tactics and we will surprise them in the trial.2.The case had erupted round my head…The case had come down upon me unexpectedly and viol ently.3.No one,least of all I,anticipated that my case would snowba ll into one of the most famous trials in U.S.history.I was the last one to expect that my case would become o ne of the most famous trials in US history.4.”That’s one hell of a jury!”The jury iscompletely inappropriate.5.”Today it is the teachers,”he continued,”and tomorrow the magazines,the books,the newspapers.”“Today it is the teachers who are put on trial because of t eaching scientific theory,”he continued to say,”Soon the mag azines,the books and newspaper will not be allowed to spreadideas of science.”6.“There is some doubt about that,”Darrow snorted.“There is some doubt about whether man has reasoning p ower,”said Darrow scornfully.7....accused Bryan of calling for a duel to the death between sc ience and religion....accused Bryan of challenging a life and death strugglebe tween science and religion.8.Spectators paid to gaze at it and ponder whether they mightbe related.People had to pay in order to have a look at the ape and t o consider carefully whether they and the apes could have a co mmon ancestry.9.Now Darrow sprang his trump card by calling Bryan as a wit ness for the defense.Darrow surprised everyone by asking for Bryan as a witne ss for the defense which was a clever idea.10.My heart went out to the old warrior as spectators pushed by him to shake Darrow’s hand.I felt sorry for Bryanas the spectators rushed past him to c ongratulate Darrow.第五课 The Libido for the Ugly1.…it reduced the whole aspiration of man to a macabre and depressing joke.This dreadful scene makes all human endeavors to advance and improve their lot appear as a ghastly,saddening joke.2.The country itself is not uncomely,despite the grime of the endless mills.The country itself is pleasant to look at,despite the sooty dirt s pread by the innumerable mills in this region.3.They have taken as their model a brick set on end.The model they followed in building their houses was a brick s tanding upright.4.This they have converted into a thing of dingy clapboards, with a narrow,low-pitched roof.These brick-like houses were made of shabby,thin wooden bo ards and their roofs were narrow and had little slope.5.When it has taken on the patina of the mills it is the color of an egg long past all hope or caring.When the brick is covered with the black soot of the mills it ta kes on the color of a rotten egg.6.Red brick,even in a steel town,ages with some dignity. Even in a steel town,old red bricks still appear pleasing to the eye.7.I award this championship only after laborious research a nd incessant prayer.I have given Westmoreland the highest award for ugliness after having done a lot of hard work and research and after contin uous praying.8.They show grotesqueries of ugliness that,in retrospect,becom e almost diabolical.They show such fantastic and bizarre ugliness that,in looking b ack,they become almost fiendish and wicked.9.It is incredible that mere ignorance should have achieved such masterpieces of horror.It is hard to believe that people built such horrible houses just because they did not know what beautiful houses were like. 10.On certain levels of the American race,indeed,there see ms to be a positive libido for the ugly…People in certain strata of American society seem definitely to hunger after ugly things;while in other less Christian strata,pe ople seem to long for things beautiful.11.They meet,in some unfathomable way,its obscure and unintelligible demands.These ugly designs,in some way that people cannot understan d,satisfy the hidden and unintelligible demands of this type of mind.12.Out of the melting pot emerges a race which hates beaut y as it hates truth.The place where this psychological attitude is found is the Unit ed States.1.The cultural diversity of Shanghai Expo is the richest ever se en on earth.2.The poverty of that region is beyond imagination.3.Don’t ask him about his father’s death in the car accident;d on’t even allude to it.4.On the cast expanses of wilderness there is not a single tree in sight.5.Despite severe natural catastrophe,people in the stricken ar eas still believe in love and the future.6.On the whole your report is well-written,but there is still pl enty of room for improvement.7.I’ve made up my mind not to buy a car as I prefer to ride a bi le in the city.8.Many children’s love of Internet games borders upon crazin ess.第六课 Mark Twain-Mirror of America。
VIII. F. Scott Fitzgerald, The Great Gatsby(Ware: Wordsworth Editions Limited, 1993), pp.93-103A.Representative Passages1. “He stretched out his hand desperately as if to snatch only a wisp of air,to save a fragment of the spot that she had made lovely for him.But it was all going by too fast now for his blurred eyes and he knew that he had lost that part of it,the freshest and the best,forever.”(97)2. “He must have looked up at an unfamiliar sky through frightening leaves and shivered as he found what a grotesque thing a rose is and how raw the sunlight was upon the scarcely created grass.A new world,material without being real,where poor ghosts,breathing dreams like air,drifted fortuitously about...like that ashen,fantastic figure gliding towards him through the amorphous trees.”(103)B. Setting1. Time: the day after the car accident2. Location: Gatsby’s houseC. Main Characters1. Mr Gatsbya. cloth:“pink rag of a suit”(98)b. expression:“heavy with dejection or sleep”(93) “look at me challengingly”(96) “radiant and understanding smile”(98)c. identity(past):“a penniless young man without past.”(94)2. Daisy:a. cloth:“with the beads and chiffon of an evening dress tangled among dying orchids on the floor.”(96)b. expression: “quality of nervous”(96)c. daily life:“keep half dozen dates a day with half a dozen men”(96)d. identity:“nice girl”(94)3. George Wilson: “half -knowing,half-bewildered look”(100) “shook his head,his eyes narrowed and his mouth widened slightly with the ghost of a superior.”(101) “acting sort of crazy”(102)D. Episodes1. Gatsby was worried about Daisy.He told me the happy day with Daisy and explained why they were not together now.2. Gatsby was very disappointed with the reality.He hoped Daisy would call him but no telephone message arrived. “He had lost the old warm world,paid a high price for living too long with a single dream”(103)3. Wilson wanted to find the murder but he mistook Gatsby for murder and killed him in the swimming pool.4. Wilson committed suicide.E. Imagery1. Daisy: “gleaming like sliver”(95)2. Beale Street Blues: “hopeless comment of the Beale Street Blues while a hundred pairs of golden and sliver slippers shuffled the shining dust.”(96)3. Pink: “pink rag of a suit”(98)4. Daisy’s house:“it was as casual a thing to her as his tent out at camp was to him.”(94)。
A painting is more than the sum of its parts. A cow by itself is just a cow. A meadow by itself is just grass, flowers. And the sun peeking through the trees is just a beam of light. But you put them all together and it can be magic.一幅画不是众多物品简单拼集而成的。
牛不过一头牛,草地也只有青草和鲜花,而穿过树枝的阳光也不过不过一束光,但假如将它们放到一同,就会产生魔一般的魅力。
The higher I got, the more amazed I was by the view.我爬得越高,眼前的景色便愈发迷人。
Some days the sunsets would be purple and pink. And some days they were a blazing orange setting fire to the clouds on the horizon. It was during one of those sunsets that my father's idea of the whole being greater than the sum of its parts moved from my head to my heart.有时夕阳浮起紫红的余晖,有时发散出橘红色的火光燃起天边的彩霞。
在这灿烂的日落情景中,我慢慢意会了父亲所说的整体胜于局部总和的道理。
Sometimes a little discomfort in the beginning can save a whole lot of pain down the road.有时开初的隐忍能够防止一路的痛苦。
Snow is a magical part of winter,transforming the world into a serene and beautiful landscape.Heres an essay about snow scenery that could inspire a middle school student:The Enchantment of SnowWinter,the season of frost and chill,is often dreaded for its harshness.However,it is also the season that brings with it a spectacle of nature that is unparalleled in its beauty the snow.Snowflakes,the delicate crystalline structures that drift down from the heavens,are the quintessential symbol of winters charm.As the first snowflakes begin to fall,the world is blanketed in a hush.The usual hustle and bustle of life seem to quiet down,as if in reverence to the silent ballet of these icy dancers.The air turns crisp,and the sky,heavy with clouds,releases its burden in the form of these gentle,white specks.The transformation is gradual but mesmerizing.Trees,once barren,now wear a cloak of white,their branches bending under the weight of the accumulating snow.The ground, once a patchwork of colors,is now a canvas of pure white,unmarred by footprints. Rooftops,cars,and benches all don the same uniform,as if the world has decided to dress in its finest for the winter festival.The snowcovered landscape is a photographers dream.Every angle presents a new perspective,a new story to tell.The contrast between the stark white of the snow and the deep blue of the winter sky is breathtaking.The sun,when it decides to peek through the clouds,casts a warm glow that highlights the intricate patterns of the snowflakes,making them sparkle like diamonds.Children are the first to embrace the joy that snow brings.They rush out,bundled up in their warmest clothes,to play in the snow.The sound of laughter fills the air as they build snowmen,engage in snowball fights,and slide down the snowy slopes.Their cheeks are rosy from the cold,but their eyes sparkle with the excitement of the season.The snow also brings a sense of tranquility.It muffles the noise of the city,creating a peaceful ambiance that is perfect for introspection.Many find solace in a quiet walk in the snow,listening to the soft crunch underfoot,and watching the snowflakes gently fall and settle on their clothes.Yet,the beauty of snow is fleeting.As the sun rises higher,the snow begins to melt,revealing the world beneath.The snowman that stood proudly in the park melts away, leaving only a puddle as a testament to its existence.The snowcovered trees shed their white blanket,returning to their original state.The world,once again,is set to its usual pace.Despite its transient nature,the memory of a snowcovered landscape lingers in the hearts of those who witness it.The enchantment of snow is not just about its physical beauty, but also about the joy,tranquility,and wonder it brings to our lives.It is a reminder of the everchanging nature of life and the beauty that can be found in each moment.In conclusion,snow is a natural phenomenon that holds a unique place in the hearts of many.It is a season of change,of beauty,and of joy.As we watch the world transform under a blanket of snow,we are reminded of the simple yet profound beauty that nature has to offer.This essay captures the essence of a snowcovered landscape and the emotions it evokes. It is a tribute to the enchanting beauty of winter and the magic of snow.。
a r X i v :0706.1053v 2 [a s t r o -p h ] 30 J a n 2008Mon.Not.R.Astron.Soc.000,000–000(0000)Printed 1February 2008(MN L A T E X style file v2.2)Glimpsing through the high redshift neutral hydrogen fogS.Gallerani 1⋆,A.Ferrara 1†,X.Fan 2‡,T.Roy Choudhury 3§1SISSA/International School for Advanced Studies,via Beirut 2-4,34014Trieste,Italy2Steward Observatory,The University of Arizona,Tucson,AZ 85721,USA 3Institute of Astronomy,Madingley Road,Cambridge CB3OHA,UK1February 2008ABSTRACTWe analyze the transmitted flux in a sample of 17QSOs spectra at 5.74≤z em ≤6.42to obtain tighter constraints on the volume-averaged neutral hydrogen fraction,x HI ,at z ≈6.We study separately the narrow transmission windows (peaks)and the wide dark portions (gaps)in the observed absorption spectra.By comparing the statistics of these spectral fea-tures with a semi-analytical model of the Ly αforest,we conclude that x HI evolves smoothly from 10−4.4at z =5.3to 10−4.2at z =5.6,with a robust upper limit x HI <0.36at z =6.3.The frequency and physical sizes of the peaks imply an origin in cosmic underdense regions and/or in HII regions around faint quasars or galaxies.In one case (the intervening HII re-gion of the faint quasar RD J1148+5253at z =5.70along the LOS of SDSS J1148+5251at z =6.42)the increase of the peak spectral density is explained by the first-ever detected transverse proximity effect in the HI Ly αforest;this indicates that at least some peaks result from a locally enhanced radiation field.We then obtain a strong lower limit on the foreground QSO lifetime of t Q >11Myr.The observed widths of the peaks are found to be systemati-cally larger than the simulated ones.Reasons for such discrepancy might reside either in the photoionization equilibrium assumption or in radiative transfer effects.Key words:cosmology:large-scale structure of Universe -intergalactic medium -quasars:absorption lines1INTRODUCTIONAlthough observations of cosmic epochs closer to the present have indisputably shown that the InterGalactic Medium (IGM)is in an ionized state,it is yet unclear when the phase transition from the neutral state to the ionized one started.Thus,the redshift of reion-ization,z rei ,is still very uncertain.After the first year WMAP data a possible tension was identi-fied between CMB and SDSS results.The high electron-scattering optical depth inferred from the TE-EE power spectra τe ≈0.17(Kogut et al.2003;Spergel et al.2003)seemed difficult to be recon-ciled with the strong evolution in the Gunn-Peterson optical depth τGP at z =6(Fan et al.2001;Fan et al.2003),accompanied by the appearance of large dark portions in QSO absorption spec-tra (Becker et al.2001;Djorgovski et al.2001;Fan et al.2006,hereafter F06).The 3-yr WMAP results have released the above tension by providing a smaller value for τe ≈0.1,which im-plies z rei ≈11for a model with instantaneous reionization (Page et al.2006;Spergel et al.2006).However,an increasing number⋆E-mail:galleran@sissa.it †E-mail:ferrara@sissa.it ‡E-mail:fan@ §E-mail:chou@of LAEs are routinely found at z >6(e.g.Stern et al.2005;Iye et al.2006;Stark et al.2007),possibly requiring a substantial free electron fraction,resulting in an IGM relatively transparent to Ly αphotons.Constraints on the IGM ionization state derived by using Ly αforest spectroscopy must take into account the extremely high sen-sitivity of τGP to tiny neutral hydrogen amounts.Indeed,a volume averaged neutral hydrogen fraction as low as x HI ∼10−3(Fan et al.2002)is sufficient to completely depress the transmitted flux in QSO absorption spectra;thus,the detection of a Gunn-Peterson trough only translates into a lower limit for x HI .For this reason,recently,many studies have tried to clarify if the SDSS data effec-tively require that the IGM was reionized as late as z ≈6(Gallerani et al.2006,hereafter GCF06;Becker et al.2006):in particular,GCF06have shown that QSO observational data currently avail-able are compatible with a highly ionized Universe at that redshift.Clearly the determination of the reionization epoch is strictly related to the measurement of the neutral hydrogen fraction at z ≈6.To investigate this issue many different approaches can be used.To start with,it is worth mentioning that many authors have tried to constrain x HI at high redshift by analyzing statisti-cally the optical depth inside HII regions around high redshift QSO (Mesinger &Haiman 2004;Mesinger &Haiman 2006),or by mea-suring the QSO bubble sizes (Wyithe &Loeb 2004;Wyithe et al.2S.Gallerani,A.Ferrara,X.Fan,T.RoyChoudhuryFigure1.Left panel:Evolution of the volumefilling factor of ionized regions for the early(red solid lines)and late(blue dotted lines)reionization models. Middle panel:V olume-averaged photoionization rateΓ−12=ΓHI/10−12s−1.Thefilled circles,empty circles,filled triangles and empty triangles show results obtained by F06,MM01,B05and B07,respectively.Right panel:Evolution of the neutral hydrogen fraction.Thick lines represent average results over 100LOS,while the thin lines denote the upper and lower neutral hydrogen fraction extremes in each redshift interval.Solid circles represent neutral hydrogen fraction estimates by F06;empty squares denote the results obtained in this work.2005;Bolton&Haehnelt2007b;Maselli et al.2007,Lidz et al.2007).However,sufficient ground for controversy remains due tointrinsic uncertainties of the various techniques.By deriving sizes of HII bubbles surrounding observed z=6.5LAEs,Malhotra&Rhoads2005have provided an upper limitfor the neutral hydrogen fraction x HI 0.2−0.5.This result isin quite good agreement with the upper limit x HI 0.45found byKashikawa et al.2006,by interpreting the deficit measured at thebright end of the LAE Luminosity Function at z>6as a suddenchange in the intergalactic neutral hydrogen content.Nevertheless,the increasing attenuation with redshift of the Lyαline transmissioncould be partially explained as a consequence of the evolution inthe mass function of dark matter halos,thus implying a much lowerupper limit,x HI<0.05−0.2(Dijkstra et al.2007).GRB spectroscopy has also tentatively used to constrain x HI;Totani et al.2006have observed a damping wing at wavelengthslarger than the Lyαemission line,finding that this feature can beexplained at best by assuming an intervening damped Lyαsystemimmersed in a fully ionized IGM,and quoting an upper limit ofx HI<0.17and0.60(68%and95%confidence levels,respec-tively).Finally,the width distribution of dark portions(gaps)seen inQSO absorption spectra has been recently introduced in order toconstrain the IGM ionization state(Paschos&Norman2005;F06;GCF06).F06has used the dark gap distribution,as observed in19high-z QSO spectra,to put a preliminary upper limit on the IGMneutral fraction x HI<0.1−0.5.GCF06,by analyzing the sta-tistically properties of the transmittedflux in simulated absorptionspectra,have shown that the gap and peak(i.e.transmission win-dows)width statistics are very promising tools for discriminatingbetween an early(z rei>6)and a late(z rei≈6)reionization sce-nario.Here we combine the previous two results:by comparing theobserved transmittedflux in high-z QSO spectra with theoreticalpredictions we obtain tighter constraints on the neutral hydrogenfraction around z=6,a crucial epoch in the reionization history.The plan of the paper is the following:in Section2we de-scribe the semi-analytical modeling adopted;in Section3we com-pare observational data with simulations.The implications of thiscomparison are given in Section4;in Section5we evaluate therobustness of our method against the specific line of sight to thehighest redshift QSO.The conclusions are summarized in Section6.2SIMULATIONSThe radiation emitted by QSOs could be absorbed through Lyαtransition by the neutral hydrogen intersecting the line of sight,theso-called Gunn-Peterson(GP)effect.The Lyαforest arises fromabsorption by low amplitude-fluctuations in the underlying bary-onic densityfield(Bi,B¨o rner&Chu1992),and is a natural conse-quence of the hierarchical structure formation expected in the con-text of CDM cosmologies1.To simulate the GP optical depth(τGP)distribution we use themethod described by GCF06,whose main features are recalled inthe following.The spatial distribution of the baryonic densityfieldand its correlation with the peculiar velocityfield are taken into ac-count adopting the formalism introduced by Bi&Davidsen1997.To enter the mildly non-linear regime which characterizes the Lyαforest absorbers we use a Log-Normal model introduced by Coles&Jones1991,widely adopted later on(Bi1993;Bi&Davidsen1997;Choudhury,Padmanabhan,&Srianand2001;Choudhury,Srianand,&Padmanabhan2001;Viel et al.2002;GCF06).In par-ticular,GCF06have compared various Lyαstatistics,namely theProbability Distribution Function(PDF)and the Gap Width dis-tribution,computed using the Log-Normal distribution with those1Throughout this paper we will assume aflat universe with total matter,vacuum,and baryonic densities in units of the critical density ofΩm=0.24,ΩΛ=0.76,andΩb h2=0.022,respectively,and a Hubble constantof H0=100h km s−1Mpc−1,with h=0.73.The parameters definingthe linear dark matter power spectrum are n=0.95,d n/d ln k=0,σ8=0.82.Note that we have chosen aσ8value higher than the WMAP3one(0.74).Indeed Viel et al.2006,by combining WMAP3data with SDSSones,foundσ8≈0.78(0.86)analyzing high(low)resolution Lyαforestdata.Mpc are physical unless differently stated.Glimpsing through the high redshift neutral hydrogen fog3 Figure2.Left panel:Evolution of the Gunn-Peterson optical depth for early(ERM,solid red line)and late(LRM,blue dotted).Thick lines represent average results on100LOS for each emission redshift,while the thin lines denote the upper and lower transmission extremes in each redshift bin,weighted on100 LOS.Filled and empty circles are observational data from Songaila2004and F06,respectively.Middle panel:Probability Distribution Function(PDF)of the flux at z=6.0.Filled circles are obtained by Fan et al.2002.Thick lines represent simulated results averaged over500LOS,while the thin lines denote cosmic variance.Right panel:Gap Width distribution in the redshift range5.0-5.5.Simulated results are compared with observations by Songaila&Cowie2002(filled circles).The errors associated to both simulated and observed results denote cosmic variance.obtained from HYDROPM simulations,finding a good agreementbetween the results.For a given IGM temperature,the HI fraction,x HI,can be computed from the photoionization equilibrium as afunction of the baryonic densityfield and photoionization rate dueto the ultraviolet background radiationfield.For all these quantitieswe follow the approach of Choudhury&Ferrara2006,hereafterCF06.By assuming as ionizing sources QSOs,PopII and PopIIIstars(the latter neglected here,see below),their model providesexcellentfits to a large number of observational data,namely theredshift evolution of Lyman-limit systems,Lyαand Lyβopticaldepths,electron scattering optical depth,cosmic star formation his-tory,and the number counts of high redshift sources.In the CF06model,a reionization scenario is defined by the product of twofree parameters:(i)the star-formation efficiency f∗,and(ii)theescape fraction f esc of ionizing photons of PopII and PopIII stars;it is worth noting that these parameters are degenerate,since dif-ferent parameter values could provide equally goodfits to observa-tions.In this work,byfitting all the above observational constraints,we select two sets of free parameters values yielding two differentreionization histories:(i)an Early Reionization Model(ERM)for(f∗,P opII=0.1;f esc,P opII=0.07),and(ii)a Late ReionizationModel(LRM)for(f∗,P opII=0.08;f esc,P opII=0.04).We donot consider contributions from PopIII stars,as PopII stars aloneyieldτe=0.07(0.06)for ERM(LRM),marginally consistentwith WMAP3results2.Fig.1shows the global properties of the two reionization modelsconsidered.In the ERM the volumefilling factor of ionized regions,Q HII=V HII/V tot=1at z≤7;in the LRM it evolves from0.65to unity in the redshift range7.0-6.0,implying that the Universe isstill in the pre-overlap stage at z≥6,i.e.the reionization processis not completed up to this epoch.In the middle panel of the sameFigure we compare the volume-averaged photoionization rateΓHI2Small contributions from PopIII stars,i.e.f∗,P opIII=0.013(f∗,P opIII=0.08),in the ERM(LRM),would yieldτe=0.09(τe=0.08),without affecting sensitively the results below.for the two models with the recent estimate by F06,and the onesby McDonald&Miralda-Escude’2001,Bolton et al.2005,andBolton&Haehnelt2007a,hereafter MM01,B05and B07,respec-tively.Finally,the evolution of the volume-averaged neutral hydro-gen fraction for the ERM and LRM is presented in the rightmostpanel.The photoionization rate predicted by both models is in agree-ment with the results by B05and B07at in the range z=4.0<z<6,whereas at z=5.5(6)the ERM is characterized by a pho-toionization rate which is≈2(6)times larger than the estimates byF06.In spite of these differences,our predictions for x HI are con-sistent with F06measurements.This apparent contradiction doesnot come as a surprise.In fact,the derivation ofΓHI requires anassumption concerning the IGM density distribution.When mea-suringΓHI at5<z<6,F06assume the density ProbabilityDistribution Function given by Miralda-Escude’et al.2000,here-after MHR3.We instead adopt a Log-Normal(LN)model whichpredicts a higher probability tofind overdensities∆=ρ/¯ρ 1than MHR.For example,at z=6and for∆≈1.5,P LN(∆)≈2×P MHR(∆)).For this reason,onceτGP isfixed to the observedvalue,the LN model requires a higherΓHI.As x HI∝∆,these twoeffects combine to give a values of x HI consistent with the data.3COMPARISON WITH OBSERV ATIONS3.1Control statisticsWefirst test the predictions of our model by applying various sta-tistical analysis to the simulated spectra and comparing our resultswith observations.Specifically,we use the following control statis-tics:(i)Mean Transmitted Flux evolution in the redshift range2−6;3F06requireΓHI to match the MM01measurement at z=4.5.Thisestimate is based on a mean transmittedflux(¯F=0.25)which is lowerthan the more recent measurements¯F≈0.32by Songaila2004,whichimpliesΓHI≈0.3.4S.Gallerani,A.Ferrara,X.Fan,T.RoyChoudhuryFigure rgest Gap Width distribution for the LR and the HR cases (left and right,respectively).Filled circles represent the result of the analysis of the 17QSOs observed spectra.Solid red (dotted blue)lines show the results obtained by the semi-analytical modeling implemented for the ERM (LRM).Vertical error bars measure poissonian noise,horizontal errors define the bin for the gap widths.(ii)Probability Distribution Function (PDF)of the transmitted flux at the mean redshifts z =5.5,5.7,6.0;(iii)Gap Width (GW)dis-tribution in 3.5≤z ≤5.5.For what concerns the GW statis-tics we define gaps as contiguous regions of the spectrum havinga τGP >2.5over rest-frame wavelength (λRF )intervals >1˚A.This method was first suggested by Croft (1998)and then adopted by various authors (Songaila &Cowie 2002;Paschos &Norman 2005;F06;GCF06).The comparison of model and observational results in terms of the above three statistics is plotted in Fig.2.By checking our models we follow the same approach of GCF06,to which we refer for a complete description of the technical details.The outcome of the test is encouraging,as both ERM and LRM successfully match the observational data at z ≤6for the control statistics considered.This allows us to confidently proceed the comparison with more advanced statistical tools.3.2Advanced statisticsSince at z ≈6regions with high transmission in the Ly αforest become rare,an appropriate method to analyze the statistical prop-erties of the transmitted flux is the distribution of gaps.In partic-ular GCF06suggested that the Largest Gap Width (LGW)and the Largest Peak Width (LPW)statistics are suitable tools to study the ionization state of the IGM at high redshift 4.The LGW (LPW)dis-tribution quantifies the fraction of LOS which are characterized by the largest gap (peak)of a given width.As far as this work is con-cerned,we apply the LGW and the LPW statistics both to simu-lated and observed spectra with the aim of measuring the evolution of x HI with redshift.We use observational data including 17QSOs obtained by F06.4The definition of “peak”in the transmitted flux is similar to the “gap”one.A peak is a contiguous region of the spectrum over λRF intervalsgreater than the observed pixel size (≈0.5˚A)characterized by a transmis-sion above a given flux threshold (F th =0.08in this work).We divide the observed spectra into two redshift-selected sub-samples:the “Low-Redshift”(LR)sample (8emission redshifts 5.7<z em <6),and the “High-Redshift”(HR)one (9emission redshifts 6<z em <6.4).Simulated spectra have the same z em distribution of the observed samples.For most QSOs we considerthe (λRF )interval 1026-1200˚Aand we normalize each width to the corresponding redshift path.Note that the LOS do not extend up to z em ;the upper (lower)limit of the interval chosen ensures that we exclude from the analysis the portions of the spectra penetrat-ing inside the QSO HII (Ly β)region.For the QSOs SDSS J1044-0125and SDSS J1048+4637we choose different intervals,namely 1050-1183and 1050-1140,respectively.These two objects have been classified as BAL QSO (Goodrich et al.2001;Fan et al.2003;Maiolino et al.2004),since their spectra present Broad Absorp-tion Lines associated with highly ionized atomic species (e.g.SiIV ,CIV).By selecting the above intervals we exclude those portions of the spectra characterized by CIV absorption features which extend to z ≈5.56(z ≈5.75)in SDSS J1044-0125(SDSS J1048+4637).Observed data were taken with a spectral resolution R ≈3000−6000;simulated spectra have been convolved with a gaussian of F W HM =67km /sec ,providing R ∼4500.Moreover each observed/simulated spectrum has been rebinned to a resolution of R =2600.Finally,we add noise to the simulated data such that the flux F in each pixel is replaced by F +G (1)×σn ,where G (1)is a Gaussian random deviate with zero mean and unit variance,and σn is the observed noise r.m.s deviation of the corresponding pixel.The results provided by the statistics adopted in this study are sensitive to the S/N ratio,since spurious peaks could arise in spectral regions with noise higher than the F th adopted.Indeed,the shape of the LGW/LPW distributions depends on the F th cho-sen.Thus,we consider two different values for F th ,namely 0.03and 0.08,respectively,and,for both of them,compute preliminary LGW/LPW distributions.Finally,the LGW/LPW distributions pre-sented are obtained as the mean of the preliminary ones,weighted on the corresponding errors (See Appendix A for a detailed dis-cussion).In our analysis we do not consider 2QSOs presentedGlimpsing through the high redshift neutral hydrogen fog5Figure rgest Peak Width distribution for the LR and the HR cases (left and right,respectively).Filled circles represent observational data obtained by analyzing the observed spectra of the 17QSOs considered.Solid red (dotted blue)lines show the results obtained by the semi-analytical modeling implemented for the ERM (LRM).Vertical error bars measure poissonian noise,horizontal errors define the bin for the peak widths.by F06,namely SDSS J1436+5007and SDSS J1630+4012,since these spectra have significantly lower S/N to apply LGW/LPW tests (continuum S/N 7).3.2.1LGW distributionWe now discuss the LGW distribution for observed/simulated spec-tra;the results are shown in Fig.3.The QSOs emission redshifts used and the λRF interval chosen for the LR sample are such that the mean redshift of the absorbers is z =5.26,with a mini-mum (maximum)redshift z min =4.69(z max =5.86),and a r.m.s.deviation σ=0.06.For the HR sample it is z =5.55,z min =4.90,z max =6.32,σ=0.14.The observed LGW dis-tribution evolves rapidly with redshift:in the LR sample most ofthe LOS are characterized by a largest gap <40˚A,whereas gaps as large as 100˚Aappear in the HR sample.This means that LOS to QSOs emitting at z em 6encounter “optically thick”regions whose size is ≤20Mpc,while for z em 6blank regions of size up to 46Mpc are present.Superposed to the data in Fig.3are the predicted LGW distri-butions corresponding to ERM and LRM,obtained by simulating 800/900LOS in the LR/HR case,corresponding to 100LOS for each emission redshift in each sample.In our ERM simulated spec-tra,at z ≈6gaps are produced by regions characterized by amean overdensity ¯∆≈1(∆min =0.05,∆max =18)with a x HI ≈10−4,averaging on 100LOS (x HI ,min =1.1×10−5,x HI ,max =3.6×10−4).It results that both the predicted LGW distributions provide a good fit to observational data.We exploit the agreement between the sim-ulated and observed LGW distributions to derive an estimate ofx HI ,shown in Fig.1.We find log 10x HI =−4.4+0.84−0.90at z ≈5.35.5The x HI value quoted is the mean between the estimates predicted by the ERM and the LRM.Moreover,we consider the most conservative case in which the errors for the measurement of the neutral hydrogen fraction areBy applying the same method to the HR sample we constrain theneutral hydrogen fraction to be within log 10x HI =−4.2+0.84−1.0at z ≈5.6.Although the predicted LGW distributions are quite similar for the two models considered,yet some differences can be pointed out.Both for the LR and HR cases the early reionization LGW distribu-tion provides a very good match to the observed points,thus sug-gesting z rei 7.The agreement is satisfactory also for the LRM,but it is important to notice that late reionization models predict toomany largest gaps ≈60˚Ain the LR case and too few gaps ≈20˚A in the HR one.Given the limited quasar sample available,the statis-tical relevance of the LRM discrepancies is not sufficient to firmly rule out this scenario.However,since in the HR case 40%of the lines of sight extend at z 6,we can use the LRM results to put an upper limit on x HI at this epoch.Indeed in the HR case we find that a neutral hydrogen fraction at z ≈6higher than that one predicted by the LRM would imply an even worst agreement with observa-tions,since a more abundant HI would produce a lower (higher)fraction of LOS characterized by the largest gap smaller (higher)than 40˚Awith respect to observations.Thus,this study suggests x HI <0.36at z =6.32(obtained from the maximum value for x HI found in the LRM at this epoch).3.2.2LPW distributionNext,we apply the Largest Peak Width (LPW)statistics (Fig 4)to both observed and simulated spectra.From the observed LPW dis-tribution we find that,in the LR (HR)sample,about 50%of thelines of sight exhibit peaks of width <12(8)˚A.In more details,the size P max of the largest transmission regions in the observed sample are 3 P max 10(1 P max 6)Mpc at z =5.3(5.6).The frequency and the amplitude of the transmission regionsprovided by the minimum x HI value found in the ERM and the maximum one in the LRM.6S.Gallerani,A.Ferrara,X.Fan,T.Roy Choudhury rapidly decrease toward high redshift.This could be due both tothe enhancement of the neutral hydrogen abundance at epochs ap-proaching reionization or to evolutionary effects of the densityfield (Songaila2004).In fact the growth factor D+of densityfluctua-tions decreases with redshift(D+(z=6)=3/5×D+(z=3)forΛCDM),thus implying a low density contrast at z=6with re-spect to later epochs.Stated differently,underdense regions that are transparent at z=3,were less underdense at z=6,thus blocking transmission.As a consequence of the densityfield evolution to-ward higher z,only few/small peaks survive and wide GP troughs appear.Superposed to the data in Fig.4are the predicted LPW distri-butions corresponding to ERM and LRM,obtained by simulating800/900LOS in the LR/HR case.In our ERM simulated spectra,at z≈6,gaps are interrupted by narrow transparent windows(i.e.peaks)originating from underdense regions with¯∆≈0.1, averaging on100LOS(∆min=0.03,∆max=0.26)andx HI≈2×10−5,(x HI,min=7.8×10−6,x HI,max=3.6×10−5). Regions characterized by∆∈[0.05;0.26]and x HI∈[1.1×10−5;3.6×10−5]could correspond to both gaps or peaks depend-ing on redshift and peculiar motions of the absorbers producing them.By comparing the simulated LPW distributions with the ob-served one,it is evident that simulations predict peak widths thatare much smaller than the observed ones both for LR and HR cases.In particular,in no LOS of our simulated samples wefind peakslarger than8˚A.The disagreement between the observed and simu-lated LPW distributions does not affect the estimate of x HI throughthe LGW distributions,since at high redshift the peaks are narrow( 10˚A).We discuss the possible reasons for this discrepancy inthefinal Section.4PHYSICAL INTERPRETATION OF THE PEAKSThe most natural interpretation for the peaks is that they correspondto underdense regions,where the low HI density of the gas allowsa high transmissivity.However,in principle they could also arise if individual ionized bubbles produced by QSOs and/or galaxies are crossed by the LOS.In the latter case the typical physical size and frequency of such semi-transparent regions must be related to the emission properties and masses of such objects.Stated differently,the fraction of LOS,f LOS,having the largest peak width equal toP max can be interpreted as the probability℘to intersect an HII region of radius R HII around a dark matter halo hosting either aQSO or a galaxy along the redshift path(z i−z f)spanned by the LOS.The comoving number density n h of dark matter halos ofmass M h is related to℘through the following equation:n h(M h)=3c(πR2HII)−1h(1+z)3/2|z f z i i−1℘,(1)We take R HII=1(10)Mpc,consistent with the smaller(larger) size P max of the observed largest peaks in the HR(LR)sample. As it is likely that statistically the LOS crosses the bubble with non-zero impact parameter,adopting R HII=P max seems a rea-sonable assumption.By further imposing℘=f LOS wefind that n h=3.7×10−6(2.2×10−8)Mpc−3for P max=1(10)Mpc in the redshift range z i=5to z f=6.Given our cosmology, such halo number density can be transformed at z=5.5into a typical halo mass of M h 1012(1013)M⊙(Mo&White2002). Thus,the halos hosting the putative luminous sources producing the peaks must be massive.Note that this result holds even if the QSO is shining only for a fraction of the Hubble time t Q/t H≈10−2at z=5.5.In addition to the peak frequency,additional constraints on the properties of the ionizing sources come from bubble physical sizes.4.1QSO HII regionsFirst,we consider the case in which the largest peaks are produced by HII regions around QSOs.The bubble size R HII is related to the ionizing photons emission rate˙Nγand QSO lifetime t Q as R HII=…3˙Nγt Qc(1+¯z)Glimpsing through the high redshift neutral hydrogen fog7 initial neutral fraction,x HI 0.1,before the QSO turns on.Theexpansion of the HII region in such environment would result inconsiderably smaller sizes(Maselli et al.2007).In this case,boththe host dark matter halo mass found above(M h≈1012M⊙),andthe size of the HII region would combine to give the correct fre-quency and spectral width of the observed peaks.4.2Galaxy HII regionsIn addition to QSOs,transmissivity windows could be produced byHII regions around high-z galaxies.Adopting the canonical rela-tionsM∗=f∗Ωbm p;f esc Nγ=4π6.5«3y−1R3HII,(6)where y−1=(x HI f−1∗f−1esc)/0.1and we are assuming¯nγ=4000,appropriate for a PopII stellar population with a standard Salpeter IMF;we assume thefiducial values x HI=5.6×10−5,f∗=0.1, f esc=0.01.The mass of an halo hosting a star-forming region able to produce R HII≈1(10)Mpc is2×108(2×1011)M⊙.At z≈5.5objects of these masses corresponds tofluctuations of the densityfield 1−σ(2−σ)(Barkana&Loeb2001).As for QSOs,the bubble size−peak frequency tension could be al-leviated if the galaxies live in overdense environments where the photoionization rate only supports a x HI≈0.1(resulting in a larger value of y−1,and hence of M h in eq.(6))prior to the onset of star formation in the galaxy.Obviously,the previous arguments neglect that because of clustering(Yu&Lu2005;Kramer et al. 2006),as multiple sources could power a single HII region;in or-der to getfirmer results radiative transfer cosmological simulations are required.5PEAKS FROM THE PROXIMITY EFFECTIn Sec.4,we have discussed the possibility that the observed peaks are produced by ionizing sources whose bubbles intersect the lines of sight to the target QSO.In this case one could ask if the source responsible for the HII region would be detected in the observed field.If the origin of transmissivity regions resides in bubbles around high-z galaxies,these sources are too faint to be seen in the SDSS;however,deep HST imaging(Stiavelli et al.2005)could detect such objects.On the contrary,if the HII region of a quasar in-tervenes along the LOS to an higher redshift quasar,thefirst could be observed in the SDSSfield.Mahabal et al.2005have discovered a faint quasar(RD J1148+5253,hereafter QSO1)at z=5.70in thefield of the high-est redshift quasar currently known(SDSS J1148+5251,hereafter QSO2)at z=6.42.In this Section we study the QSO2transmit-tedflux,in order to analyze the proximity effect of QSO1on the QSO2spectrum.For clarity,Fig.5presents a schematic picture of the considered geometry.As the redshift z=5.70quoted by Ma-habal et al.2005is based on the peak of the Lyαemission line,and the estimated error from such procedure is∆z≈0.05(Goodrich et al.2001),we assume z QSO1em=5.65and we discuss this issue in further details in Appendix B.The two QSOs have a projected separation of109”,which cor-responds to R⊥=0.66Mpc.The line of sight to QSO2intersects the bubble produced by QSO1for a redshift path(∆z prox)whose length depends on the radius of the HII region(R HII)itself.We find R HII=39Mpc,by plugging in eq.(2)the following values: t Q=1.34×107yr,x HI=8.4×10−5,˙Nγ=8.6×1055sec−1, where x HI is provided by the mean value between those predicted by our models at z=5.7(see rightmost panel of Fig.1),while˙Nγis compatible with the luminosity of a QSO3.5magnitudes fainter than QSO2(Mahabal et al.2005).In this Section,we also take into account relativistic effects which could squash the ionization front along the LOS(White et al.2003;Wyithe et al.2005b;Yu2005; Shapiro et al.2006).The apparent size of the HII region,computed following the method outlined in Yu2005,is shown in Fig.5.By zooming the region close to QSO1(small box in Fig.(5))it is clear that the apparent size of the HII region extends up to2Mpc in the direction toward QSO2.Given R HII,taking into account rel-ativistic effects,the region∆z prox extends from z=5.16up to z=5.68.We re-compute x HI along the LOS to QSO2,adding to the uniform UVB photoionization rateΓHI the photoionization rateΓQSO1HIprovided by QSO1,obtained starting from the follow-ing equations:ΓQSO1HI=4πZ∞νHI JννHI«−3dν;(7) Jν=˙NνhννHI«−αdν,(9) whereνHI is the hydrogen photoionization frequency threshold,σ0 is the Thompson scattering cross section,R is the distance fromQSO1to the LOS,˙NνHIis the rate of the emitted ionizing photons at the hydrogen photoionization frequency threshold andα=1.5 is the spectral index of the QSO continuum.Integrating eq.(9)we obtain:˙NνHI=(α−1)˙Nγα+2«˙Nγσ0。