In-orbit performance of the XMM-Newton X-ray telescopes images and spectra

a r X i v :a s t r o -p h /0309287v 1 10 S e p 2003Astronomy &Astrophysics manuscript no.INTEGRAL32February 2,2008(DOI:will be inserted by hand later)JEM-X background models ⋆J.Huovelin,1S.Maisala,1J.Schultz,1N.J.Westergaard,2C.A.Oxborrow,2P.Kretschmar,3,4and N.Lund 21Observatory,P.O.B.14(Kopernikuksentie 1),FIN-00014University of Helsinki,Finland 2Danish Space Reasearch Institute,Juliane Maries Vej 30,DK 2100Copenhagen,Denmark 3Max-Planck-Institut f¨u r Extraterrestrische Physik,Giessenbachstrasse,85748Garching,Germany 4INTEGRAL Science Data Center,Chemin d’Ecogia 16,Versoix,Switzerland Received July 15,2003;accepted Abstract.Background and determination of its components for the JEM-X X-ray telescope on INTEGRAL are discussed.A part of the first background observations by JEM-X are analysed and results are compared to predictions.The observations are based on extensive imaging of background near the Crab Nebula on revolution 41of INTEGRAL.Total observing time used for the analysis was 216502s,with the average of 25cps of background for each of the two JEM-X telescopes.JEM-X1showed slightly higher average background intensity than JEM-X2.The detectors were stable during the long exposures,and weak orbital phase dependence in the background outside radiation belts was observed.The analysis yielded an average of 5cps for the di ffuse background,and 20cps for the instrument background.The instrument background was found highly dependent on position,both for spectral shape and intensity.Di ffuse background was enhanced in the central area of a detector,and it decreased radially towards the edge,with a clear vignetting e ffect for both JEM-X units.The instrument background was weakest in the central area of a detector and showed a steep increase at the very edges of both JEM-X detectors,with significant di fference in spatial signatures between JEM-X units.According to our modelling,instrument background dominates over di ffuse background in all positions and for all energies of JEM-X.Key words.X-ray background –X-ray data analysis –INTEGRAL satellite 1.Introduction Background of X-ray and γ-ray detectors for astronomy can generally be divided in two components,di ffuse sky back-ground and instrument background .JEM-X consists of two mechanically identical telescope units (JEM-X 1and 2),with a position sensitive xenon-filledMicrostrip Gas Chamber,a collimator,and a coded mask as anoptical element in each unit (see Lund et al.2003for moredetails).There are four internal radioactive sources for spectralcalibration in the collimator of each unit.The sky image is thus a result of mathematical processingof the mask shadow pattern on the position sensitive detectors(e.g.in’t Zand 1992;in’t Zand,Heise &Jager 1994).Di ffuse sky background enters the detectors via the apertureand is a ffected by the mask and the collimator,similarly to thedistinguishable sources in the sky.Instrument background in-cludes detector signal due to interactions between cosmic radi-2Huovelin et al.:JEM-X background modelsFig.1.Spatial distribution of the background.Upper panels:JEM-X1,lower panels,JEM-X2.Left panels:Instrument back-ground,Right panels:Diffuse background.The white rectan-gles denote the positions of the calibration sources,which havebeen excluded from our analysis.The collimator signature canbe seen as weak vertical and horizontal line structures in the shadowgrams.The broad vertical lines are due to dead anodes.Also some photon leak from the calibration sources is evident.The sharp and very narrow lines are graphical artifacts causedby the plotting routine.Total intensity of each shadowgram isnormalized to1.Table1.INTEGRAL background pointings during cycle41.45324.0+210850.17000053645.0+122415.14082553645.2+122546.44277553645.3+122543.564468Huovelin et al.:JEM-X background models3Table2.The normalization factors of the background con-tinuum components(10−3photons keV−1cm−2s−1at1keV). Mean and standard deviation of values derived from the six extraction regions at each radius are given.The energy range used in thefitting is4-33keV.Diffuse denotes diffuse sky back-ground,Flat denotes theflat continuum of the instrument back-ground.Note that the normalization is determined on the basis of source spectra from1R in R out JEM-X1JEM-X2pix pix Diffuse Flat Diffuse FlatThe diffuse background decreases towards the edges of the detector,as expected.The instrument background is stronger than expected,dominating the spectrum at all radii.The ten expected K-shell lines(from the109Cd and55Fe calibration sources,collimator(Mo),and detector gas(Xe))were detected close to their nominal positions.This implies that the energy scale is correctly determined.The previously unknown weak line near13keV turned out to be the uranium L-shell line.It most likely originates in the detector beryllium window.Near the edges of the detector,the background is highly nonuniform. Additional nonuniformity in the outer parts was introduced by photon leak from calibration sources,which could not be com-pletely eliminated.We also searched for possible dependence of background on the orbital phase of the observations.The spectrum varied with a range of approximately5%between three separate or-bital sections well outside radiation belts.The variation is sta-tistically significant but small.Also dependence on solar aspect angle and particle radiation level can be utilised in the JEM-X ISSW background modelling.Significant variations were not found.The variation in the solar aspect due to different point-ings was20◦,which is probably not sufficiently large for stud-ies of an effect on instrument background.Also,there was no proper indicator of particle radiation level on INTEGRAL available during our observations to search for a correlation.4.ConclusionsWe have analyzed a part of thefirst INTEGRAL background observations with JEM-X.Estimates of the spatial and spec-tral distributions are obtained for diffuse sky background and instrument background.The total background observed for JEM-X1was28cps,for JEM-X223cps,and25cps on the average.A part(∼1/5)of the excessively large background may be due to residual Crab Nebula emission in JEM-X data.According to XSPECfitting,the diffuse background was at maximum in the centre of the detector and it decreasedra-Fig.2.Four sample background spectra extracted from differ-ent parts of JEM-X2.At the sides of the detector,a blend of K-shell lines from the spacecraft structure is seen.Note also the prominent lines in spectrum extracted from the surround-ings of the calibrationsources.Fig.3.The background extraction regions.Units in both axes are pixels.All regions cover an equal area of the detector. Exclusion of calibration sources(not shown)reduces the ac-tual area of some regions.dially towards the edge,which is due to vignetting.There is also slight asymmmetry in the spatial distribution of the diffuse background,which is caused by a small angular misalignment of the detector plane.The count rate for diffuse background was approximately20%of the total background.The instrument background intensity and spectrum are highly position dependent,with a steep increase near the edges at all radial directions.Leakage of the radiative calibration sources causes residual line emission in the neighbourhood of4Huovelin et al.:JEM-X background modelsTable3.The lines detected from the background.Line ID is the element and transitions producing the line,E is the line en-ergy in keV(Thompson et al.,2001).Subscripts1and2denote the detectors JEM-X1and2,F is the largest line strength de-tected,¯F(N)mean of detected line strengths where N is the number of regions from which the line is detected(maximum is48regions/detector).The Mn/Fe line at6.45keV is a blend of Mn Kβ(6.49keV)and Fe Kα(6.40keV).Line strengths are given in10−3photons cm−2s−1.Note that the line strengths are determined on the basis of source spectra from1Line E F1¯F1(N)F2¯F2(N)Origin the source positions.The count rate for the instrument back-ground was approximately80%of the total background.The total background level varied with a range of approx-imately5%between different orbital sections.the variation is significant,but small.Also,it is impossible to say,what fraction of this,if any,is caused by the simultaneous variation of the so-lar aspect angle of the satellite,and the unknown variations of particle radiation level.We plan to separate these effects by the support of future background observations.Although our modelling is simple,and does not provide accurate absolute estimates of physical backgroundfluxes,it yields information which can be applied to the JEM-X analysis software to properly account for background contribution in spatially resolved spectral data.A thorough analysis of JEM-X background will be presented in a future paper. Acknowledgements.Authors from the Observatory,University of Helsinki acknowledge the Academy of Finland,TEKES,and the Finnish space research programme ANTARES forfinancial support in this research.J.Schultz is grateful for thefinancial support of the Wihuri Foundation.The Danish Space Research Institute acknowl-edges support given to the development of the JEM-X instrument from the PRODEX programme.ReferencesArnaud,K.A.,1996,Astronomical Data Analysis Software and Systems V,eds.Jacoby G.and Barnes J.,ASP Conf.Series V ol.101.Covault,C.E.,Grindlay,J.E.,Manandhar,R.P.,and Braga,J.,1991, IEEE Transact.Nucl.Sci.,V ol.38,No.2.Ferguson,C.,Barlow,E.J.,Bird,A.J.,et al.,2003A&A,this volume in’t Zand,J.,1992,Ph.D.thesis,SRON.in’t Zand,J.,Heise,J.,Jager,R.,1994,A&A288,665.Lund,.N.,Brandt,S.,Budtz-Joergensen,C.,et al.,2003,A&A,this volumeMarshall,F.E.,Boldt,E.A.,Holt,S.S.,et al.,1980,ApJ235,4 Oxborrow C.A.,Kretschmar,P.,Maisala,S.,Westergaard,N.J., Larsson,S.,2002,Instrument Specific Software for JEM-X: Architectural Design Document,DSRI homepage:www.dsri.dk Thompson, A.C.,Attwood, D.T.,Gullikson, E.M.,et al.,2001,“The X-ray data booklet”,2nd ed.,Lawrence Berkley National Laboratory,Univ.of California,available at / Westergaard,N.J.,Kretschmar,P.,Oxborrow,C.A.,et al.,2003,A& A,this volumeWillmore,A.P.,Bertram,D.,Watt,M.P.,et al.,1992,MNRAS258, 621。

火星救援阿西达利亚平原好了队友们互相看着点儿All right, team, stay in sight of each other.NASA 战神三号♥ 降落地点今天让NASA以我们为傲吧Let's make NASA proud today.任务日:第18个火星日那边情况如何沃特尼How's it looking over there, Watney?你会很高兴知道坐标方格14-28区里Well, you'll be happy to hear that in grid section 14-28,颗粒大部分都比较粗糙the particles were predominantly coarse...但29区的就精细多了but in 29, they're much finer...用它们做化学分♥析♥应该很理想And they should be ideal for chem analysis.大家听到了吗Did everybody hear that?马克刚刚发现了泥土Mark just discovered dirt.我们要通知媒体吗Should we alert the media?抱歉你今天要干什么来着马丁内兹Sorry, what are you doing today, Martinez?确保飞行器还立着吗Making sure the MAV is still upright?要知道目视检查仪器I'd like you to know that visual inspection of the equipment...也是任务成功必不可少的一步is imperative to mission success.同时我还想报告飞行器的确好好立着呢I also would like to report that the MAV is still upright.沃特尼你一直开着通话频道Watney, you keep leaving your channel open,马丁内兹就会回应你which leads to Martinez responding...我们所有人就会听到which leads to all of us listening...然后我就会很烦which leads to me being annoyed.收到了马丁内兹队长想请你Roger that. Martinez, the captain would like you to please...闭上你那张利嘴shut your smart mouth.能用别的词来形容马丁内兹的嘴巴吗We'd prefer to use a different adjective to describe Martinez's mouth.贝克刚刚是不是侮辱了我Did Beck just insult me?是"贝克博士" 没错"Dr. Beck." And yes.我很乐意从这里把无线电关掉指挥官Happy to turn the radios off from here, Commander.您下令就行Just say the word.等等约翰逊Wait, Johanssen.一直保持通话是...Constant communication is the hallmark...关了Shut 'em off.不要No.不啊拜托No. Excuse me.我为我的同胞向你道个歉沃格尔I apologize for my countrymen, Vogel.道歉接受Accepted.还需要多少样本指挥官How many samples do we need, Commander?七个Seven.每个100克100 grams each.紧急情况任务状态更新有个任务状态更新We have a mission update.风暴警告A storm warning.指挥官你该进来Commander, you should come inside.你会想看看这个You're gonna want to see this.看什么What is it?A storm warning.我在今早的简报上看到了I saw that in this morning's briefing.我们会在风暴到达前回来We'll be inside before it hits.是啊但他们升级了预测Yeah, they upgraded their estimate.风暴会猛烈得多The storm's gonna be a lot worse.马丁内兹情况看上去如何Martinez, how does it look?不太妙Not good.直径1200千米角度24.41度"1,200 kilometers in diameter, bearing 24.41 degrees."那是径直冲我们来了That's tracking right towards us.根据目前的增强趋势"Based on current escalation,预计将有8600牛顿的力"estimated force of 8,600 Newtons."任务中止力是多少What's the abort force?7500牛顿7,500.超过那个飞行器就可能倾倒Anything more than that and the MAV could tip.我们要中止吗Do we scrub?启动中止程序Begin abort procedure.我们的预测是会有误差We are estimating with a margin of error.也许等一会就没事了We could wait it out.我们等等吧Let's wait it out.我们等等吧Let's wait it out.指挥官Commander?准备紧急起飞Prep emergency departure.Commander?我们得中止那是命令We're scrubbed. That's an order.马丁内兹还要多久能起飞Martinez, how long before take-off?12分钟12 minutes.任务日任务日能见度基本为零Visibility is almost zero.要是谁走丢了跟着我的宇航服遥感信♥号♥♥ Anyone gets lost, hone in on my suit's telemetry.气闸室减压中-准备好了吗-好了- You ready? - Ready.指挥官您没事吧Commander, are you okay?没事I'm okay.任务日任务日指挥官我们倾斜了10度Commander, we're at 10 degrees,超过12.3度飞行器就会倾倒and the MAV is gonna tip at 12.3.我们也许能阻止飞行器倾倒We might be able to keep the MAV from tipping.怎么办How?把通讯杆的电缆作为牵引绳Use the cables from the comms mast as guy-lines...用探测车拉着它anchor it with the rover's.小心Watch out!任务日沃特尼Watney!任务日警告检测到宇航服破损Warning. Suit breach detected.失去信♥号♥♥What happened?他被击中了He was hit.沃特尼回复Watney, report.在我们失联前Before we lost telemetry,他的减压警报响了his decompression alarm went off.约翰逊你最后一次看到他是在哪里Johanssen, where did you last see him?我不知道他在哪里I don't know where he is.沃特尼失去信♥号♥♥他宇航服上显示的生命体征如何What are the vitals on his suit?-他掉线了-什么都没有- He's offline. He's offline. - Negative.完全失去了沃特尼的信♥号♥♥A complete loss of signal on Watney.-贝克-怎么了- Beck! - Yeah.在减压的情况下他能活多久How long can he survive decompression?不足一分钟Less than a minute.排成一线向西走Line up, walk west.他也许倒在地上了可别踩着他He may be prone. We don't wanna step over him.指挥官...Commander...-10.5度了-警告过度倾斜- we're at 10.5 degrees. - Warning. Excessive tilt.再刮一阵就要到11度了Tilting to 11 with all the gusts of wind.收到Copy that.大家跟紧马丁内兹宇航服的遥感信♥号♥♥ Everyone, hone in on Martinez's suit.它会带领你们到气闸室It'll get you to airlock.进去去准备发射Get in, prep for launch.你呢指挥官What about you, Commander?我再找下他你们快走I'm gonna search a little longer. Get moving!快Go!沃特尼Watney!沃特尼回复Watney, report!飞行器已经倾斜到11.6度了The MAV's at 11.6 degrees.再刮一阵风我们就要翻了One good gust and we're tipping.假如要翻了你就发射If it tips, you launch.你真的觉得我会把你抛下吗You really think I'm gonna leave you behind?那是命令马丁内兹That's an order, Martinez.马克Mark!马克能听见我说话吗Mark! Can you hear me?马丁内兹近程雷达呢Martinez, what about the proximity radar?那东西能检测到沃特尼的宇航服吗Could that detect Watney's suit?那是用来从轨道上观测赫耳墨斯的It's made to see the Hermes from orbit...而不是观测一件宇航服上的一小块金属not a little piece of metal from a single suit.-试试吧-收到- Give it a try. - Roger.她想什么呢What is she thinking?她清楚红外线穿不过沙暴的She knows the infrared can't get through a sandstorm.她是死马当活马医了She's grasping for anything.近程雷达什么也没有检测到We've got negative contact on the proximity radar.什么都没有吗Nothing?是的我连居住舱都看不太清了No. I can barely see the HAB.指挥官我知道你不想听但是Commander, I know you don't wanna hear this, but...马克死了Mark is dead.指挥官Commander!你♥他♥妈♥怎么回事啊Hey, what the hell is wrong with you, man?我朋友刚刚死了My friend just died.我不希望我的指挥官也死了I don't want my commander to die, too.稳度警告Stability warning.我们要倾倒了We're tipping!指挥官你得回到飞船上马上Commander, you need to get back to the ship, now! 13度了13 degrees.要是失去了平衡就再也立不起来了If we pass balance, we'll never rock back.我还剩最后一招I've got one more trick left,然后我就要执行命令了指挥官and then I'm following orders, Commander.你启动了轨道机动系统吗You're firing the OMS?没错That's right.指挥官Commander!来了On my way.约翰逊走吧Johanssen, let's go.马克Mark!现在勉强维持在11.5度We're at 11.5 and holding.下令就可以出发了Ready to go on your command.准备发射Ready to launch.指挥官Commander.你得告诉我能不能起飞I need you to verbally tell me whether or not to.发射Launch.在中♥央♥标准时间凌晨4:30左右At around 4:30 A.M. central standard time...我们的卫星检测到了一场风暴our satellites detected a storm正在接近战神三号♥火星任务站approaching the Ares 3 mission site on Mars.6:45 风暴升级为强烈风暴6:45, the storm had escalated to severe...我们别无选择只能中止任务and we had no choice but to abort the mission.多亏露易丝指挥官的快速反应...Thanks to the quick action of Commander Lewis...战神三号♥宇航员正在返程宇航员贝克约翰逊astronauts Beck, Johanssen,马丁内兹以及沃格尔Martinez and Vogel...都成功登上了火星上升飞行器were all able to reach the Mars ascent vehicle...并于中♥央♥时间7:28启动了紧急发射and perform an emergency launch at 7:28 central time.不幸的是在撤离过程中...Unfortunately, during the evacuation...宇航员马克·沃特尼被飞石击中身亡astronaut Mark Watney was struck by debris and killed.指挥官露易丝以及剩余队员Commander Lewis and the rest of her team...则成功与赫耳墨斯对接were able to intercept safely with the Hermes如今正在返程回家and are now heading home.但马克·沃特尼牺牲了But Mark Watney is dead.桑德斯局长Director Sanders!氧气含量临界Oxygen level critical.氧气含量临界Oxygen level critical.氧气含量...Oxygen level...压力稳定Pressure stable.局部麻醉缝合操Fuck.好吧Okay.任务日第19个火星日居住舱铺位好吧Okay.你好这里是马克·沃特尼宇航员Hello, this is Mark Watney, astronaut.我拍摄这段日志是为了记录...I'm entering this log for the record...第19个火星日居住舱铺位以防我死了In case I don't make it.现在是第19个火星日的6点53分It is 06:53 on sol 19...而我还活着and I'm alive.显而易见的Obviously.但我猜对于我的队友和NASA而言But I'm guessing that's gonna come as a surprise 这将会是个惊喜to my crewmates and to NASA.第19个火星日居住舱铺位对全世界而言也是真的所以And to the entire world, really, so...惊喜吧Surprise.我没有死在第18个火星日I did not die on sol 18.我的猜想是...Best I can figure...这一截通讯天线断了this length of our primary communications antenna broke off...刺穿了我的生命监控器and tore through my bio-monitor...在我身上也开了个口子and ripped a hole in me as well.但其实那截天线和血But the antenna and the blood, really,封住了我宇航服上的裂缝managed to seal the breach in my suit...救了我一命which kept me alive,即便队友们一定都以为我死了even though the crew must have thought I was dead.我没有办法联♥系♥上NASAI have no way to contact NASA.而且就算是联♥系♥上了也得等上四年And even if I could, it's gonna be four years...才有载人任务能到我身边until a manned mission can reach me.我在这个设计上只能撑31天的居住舱里And I'm in a HAB designed to last 31 days.如果氧合器坏了我会窒息而死If the oxygenator breaks, I'm gonna suffocate.如果净水回收机坏了我会渴死If the water reclaimer breaks, I'll die of thirst.假如居住舱破损了我就会If the HAB breaches, I'm just gonna, kind of...内爆而死implode.假如奇迹出现上述情况都没有发生And if by some miracle, none of that happens...我最终还是会耗尽食物eventually I'm gonna run out of food.所以So...没错Yeah.好吧Yeah.约翰逊我不会死在这里I'm not gonna die here.第21个火星日任务日32...32...33...34, 35, 36.糖醋鸡Sweet and sour chicken.真空冲水感恩节之前不要打开看看有什么What do we got?任务日好了来算算吧Right, let's do the math.我们的地表任务本应是31个火星日Our surface mission here was supposed to last 31 sols.为了以防万一他们送了68个火星日的食物For redundancy, they sent 68 sols worth of food.还是6人的量That's for 6 people.我一人吃的话可以撑300个火星日So for just me, that's gonna last 300 sols...控制饮食估计能撑400个火星日which I figure I can stretch to 400 if I ration.所以我得想个办法种出够吃3年的食物So I got to figure out a way to grow three years' worth of food here.在这片不毛之地上On a planet where nothing grows.幸运的是Luckily...战神生物探索火星上的进程我是个植物学家I'm a botanist.火星将会畏惧我的植物学之力Mars will come to fear my botany powers.有机废料生物危害人类排泄物M 沃特尼任务日任务日任务日压力稳定Pressure stable.任务日订书针出来了Staple came out.第24个火星日葡萄汁去你的火星Fuck you, Mars.第31个火星日任务日约翰逊天呐Johanssen, Jesus.第36个火星日问题是水The problem is water.我铺设了126平方米的土地I have created 126 square meters of soil.但每立方米的土壤需要40升的水But every cubic meter of soil requires 40 liters of water才能耕种to be farmable.所以我得搞出来更多水So I gotta make a lot more water.好消息是我知道如何做Good thing is, I know the recipe.用氢气加上氧气再点燃You take hydrogen, you add oxygen, you burn.现在飞行器中有好几百升没用过的联氨Now, I have hundreds of liters of unused hydrazine at the MDV.假如我用铱催化剂分解联氨If I run the hydrazine over an iridium catalyst,它将分解成氮气和氢气it'll separate into N2 and H2.然后假如我直接将氢气导入一个小空间And then if I just direct the hydrogen into a small area...然后点燃它and burn it.幸运的是在人类历史上...Luckily, in the history of humanity...从没因为点燃氢气而出过什么事nothing bad has ever happened from lighting hydrogen on fire. NASA讨厌明火NASA hates fire.就因为"火会让大家死在太空"这套说辞Because of the whole "fire makes everybody die in space" thing.所以这里的所有用品都是阻燃的So, everything they sent us up here with is flame-retardant...除了一个显著的例外...with the notable exception of...马丁内兹的私人物品Martinez's personal items.抱歉了马丁内兹I am sorry, Martinez.但假如你不希望我翻你的东西的话...But if you didn't want me to go through your stuff...你就不应该把我留在这个荒芜的星球等死you shouldn't have left me for dead on a desolate planet.再说了基于我这个现状By the way, I'm figuring you're gonna be fine with this,我想你会理解的given my present situation.就靠你了Counting on you.所以没错我把自己炸飞了So, yeah, I blew myself up.我的猜想是Best guess...我计算的时候I forgot to account for忘了把我呼出的氧气算进去了the excess oxygen that I've been exhaling when I did my calculations.因为我是个白♥痴♥Because I'm stupid.好了我要回去干活儿了Yeah, I'm gonna get back to work here...等我耳鸣一停止我就开工Just as soon as my ears stop ringing.趣味附注Interesting side note,喷气推进实验室就是这么建立的this is actually how the Jet Propulsion Lab was founded.加州理工的五个学生试图制♥造♥火箭燃料Five guys at Caltech were trying to make rocket fuel...差点没把宿舍烧了and they nearly burned down their dorm.但他们没有被开除And rather than expel them...而是被赶去了附近的农场they banished them to a nearby farm,说让他们继续研究told them to keep working.因此我们就有了太空项目And now we have a space program.好了Okay.任务日任务日任务日第48个火星日第54个火星日你好呀Hey, there.国家很荣幸有马克为我们的太空项目效力The nation was blessed to have Mark serving in our space program.我们因失去他而深感悲痛While his loss will be deeply felt...NASA的全体成员将会勇往直前The men and women of NASA will soldier forth...肩负组织的使命不断前进提升Onward and upward in the mission of their agency.泰迪·桑德斯NASA局长由此他们将不辱马克的遗志By doing so, they honor the legacy Mark's leaving behind...也将确保他死得其所and they ensure his sacrifice will not be in vain.约翰森航♥天♥中心休斯顿得克萨斯州文森特·卡普尔火星任务主管NASA我有幸在此发言I have the honor of speaking不仅代表NASA的全体成员not only for the men and women of NASA...也代表了世界人♥民♥but for people all over the world...我觉得你的演讲不错I thought you gave a lovely speech, by the way.我需要你授权我的卫星观测I need you to authorize my satellite time.不可能It's not gonna happen.我们有五次战神任务的经费We're funded for five Ares missions.我觉得我能说服国会资助第六次I think I can get Congress to authorize a sixth.-不行-战神三号♥在第18个火星日就撤离了- No. - Ares 3 evac'd after 18 sols.还有价值半次任务的物资在上面There's half a mission worth of supplies up there.我可以将其按正常任务的小部分价格低价卖♥♥出I can sell it at a fraction of of the cost of a normal mission...我只想知道我们还剩什么And all I have to know is what's left of our assets.不是只有你想用卫星观测You're not the only one who needs satellite time.我们马上就要进行战神四号♥的补给任务We've got the Ares 4 supply missions coming up.现在更应关注夏帕瑞丽陨石坑We should be focusing on the Schiaparelli crater.可我们有12颗卫星呢Okay, we got 12 satellites up there.就抽空看一下Surely we can spare a few hours...这不是卫星观测的问题文斯It's not about the satellite time, Vince.我们是受到广大公众关注的We're a public domain organization.这种事必须公开透明We need to be transparent on this.没错Okay.只要我们把卫星对准那里The second we point the satellites at the hab...就是向全世界直播马克·沃特尼的尸体I broadcast pictures of Mark Watney's dead body to the world.你是担心出现公♥关♥危机You're afraid of a PR problem?当然害怕了Of course I'm afraid of a PR problem.还想通过新任务Another mission?要是一个死去的宇航员Congress won't reimburse us for a paper clip...上了《华♥盛♥顿♥邮♥报♥》的头版头条If I put a dead astronaut on the front page国会一个子儿都不会拨给我们了of the Washington post.他会一直在的泰迪他He's not going anywhere, Teddy. I mean, he's not...他不会腐烂你又不是不知道He's not gonna decompose, you know.他会一直留在那儿He's gonna be up there forever.气象学预计他的尸体正常气象运动下Meteorology estimates that he'll be covered in sand...一年内就会被黄沙掩埋From normal weather activity within a year.总不能等一年吧我们还有工作We can't wait a year. We got work to do.战神五号♥五年内都不可能发射Ares 5 won't even launch for five years.时间多着呢We have plenty of time.好吧Okay.好Okay.好你听我说Okay, consider this.现在全世界都是站在我们这边的Right now, the world's on our side.人们同情沃特尼一家人Sympathy for the Watney family.战神六号♥能把他的尸体带回来Ares 6 could bring his body home.并不是说这是战神六号♥的唯一目的Now, we don't say that's the purpose of the mission...但至少应该是其中的一部分But we make it clear that that would be a part of it.就这么定了We frame it that way.可以得到国会的支持但不能再等一年More support from congress. But not if we wait a year.如果再等一年谁都不在乎了We wait a year, nobody gives a shit.NASA 控制中心德克萨斯州休斯敦约翰森航♥天♥中心凌晨1:30明迪·帕克NASA 卫星联络部收到新信息文森特·卡普尔Vincent Kapoor?你好明迪查看以下坐标纬度: 46°42′0″经度: 22°0′0″(46.7°, -22°)文森特6-26-2.7-6-27-6-2.阿西达里亚平原Acidalia planitia.第54个火星日第18个火星日第18个火星日第54个火星日怎么回事What?第54个火星日第18个火星日第54个火星日第18个火星日第54个火星日第54个火星日第18个火星日第54个火星日你好警卫室吗Hi. Security?我是卫星监控室的明迪·帕克This is Mindy Park in Satcon.我需要紧急联络文森特·卡普尔I need the emergency contact for Vincent Kapoor.没错就是他Yes, him.对事情紧急Yes, it's an emergency!凌晨2:30有多大的可能性How sure?100%100%.安妮·蒙特罗斯信息部负责人这是在逗我吗You've got to be shitting me.证明一下你的说法Prove it to me.首先For a start...太阳能发电板被清理了The solar panels have been cleaned.有可能是风吹干净的They could have been cleaned by wind.后退一点看漫游者2号♥Back it up. Look at Rover 2.根据宇航日志According to the logs,第17个火星日指挥官露易丝把它拿出来commander Lewis took it out on sol 17...插到居住舱充电Plugged it into the hab to recharge.但是它的位置变了It's been moved.有可能她挪走了但忘了记录She could have forgotten to log the move.不不太可能No, not likely.为什么不问问露易丝Why don't we just ask Lewis?让地面通讯直接问她Let's get on capcom and ask her directly right now.不不如果沃特尼真的还活着No. No. If watney is really alive,我们不能让战神三号♥的队员知道we don't want the Ares 3 crew to know.怎么能不告诉他们How can you not tell them?他们再有十个月就能回来了They have another 10 months on their trip home.太空旅行很危险Space travel is dangerous.他们必须得集中精力不能分神They need to be alert and undistracted.但他们都以为他死了But they already think he's dead.如果发现他被活着抛弃在那儿And they'd be devastated to find out他们会更痛苦they left him there alive.可是你们都没有想清楚I'm sorry, but you have not thought this through I mean.我们怎么说啊"亲爱的美国民众What are we gonna say? "Dear America...还记得我们之前那位牺牲了Remember that astronaut we killed还举办了盛大葬礼的宇航员吗And had a really nice funeral for?他没死我们把他落在火星上了抱歉Turns out he's alive and we left him on Mars. Our bad.真诚的NASA""Sincerely, NASA."你们意识到我们会受到多少唾骂吗Do you realize the shitstorm that is about to hit us?我们怎么应对民众How are we going to handle the public?按规定24小时之后必须公布这些画面Legally, we have 24 hours to release these pictures.我们要随之发布一份声明We release a statement with them.不能让人们自己瞎琢磨We don't want people working it out on their own.是长官Yes, sir.但如果我没算错我们派遣救援之前But if my math is right, he's going to starve to death他就饿死了long before we can help him.你能想象他都经历了什么吗Can you imagine what he's going through up there?他离家五千万英里He's 50 million miles away from home.他独自一人He thinks he's totally alone.觉得已经被我们抛弃He thinks we gave up on him.这会对一个人的心理产生多大的影响What does that do to a man, psychologically?他现在到底在想什么What the hell is he thinking right now?任务日再让我听这么难听的迪斯科I'm definitely gonna die up here...我肯定会死在这里If I have to listen to any more god-awful disco music.天哪露易丝指挥官My god, commander Lewis,你就没有点能跟上时代潮流的东西吗couldn't you have packed anything from this century?♪Turn the beat around♪不我可不打算"舞力无限"No, I am not gonna "Turn the beat around."我拒绝I refuse to.桑德斯先生桑德斯先生Mr. Sanders? Mr. Sanders?为了和马克·沃特尼取得联♥系♥ What attempts have been made你们都做了什么呢to make contact with Mark Watney?我们仍在努力We're working on it.他的补给能维持生存吗Does he have enough supplies to survive?我们会研究的We'll be looking into that.官方有什么说法呢What does this say about the agency?您会辞职吗Are you gonna resign?不会No.桑德斯局长Director Sanders!第70个火星日该考虑得长远些了It's time to start thinking long term.NASA的下一个任务是战神四号♥The next NASA mission is Ares 4...它的预计着陆点在夏帕瑞丽陨石坑And it's supposed to land at Schiaparelli crater...距离这里3200公里3200 kilometers away.3200公里3,200 kilometers.四年后下一个航♥天♥小组到达的时候In four years, when the next Ares crew arrives,我必须到达着陆点I'll have to be there.也就意味着我得去陨石坑等待Which means I have to get to the crater.那么问题来了Okay, so here's the rub.我只有一辆探测车I've got one working rover最远行驶距离35公里designed to go a Max distance of 35 kilometers...之后就必须回到居住舱给电池充电Before the battery has to be recharged at the hab.这是第一个问题That's problem A.第二个问题就是这么远距离的行进Problem B is this journey's gonna take me我需要大约50天才能完成roughly 50 days to complete.所以我必须拖着So I gotta live for 50 days...一整车的补给在探测车里inside a rover with marginal life support生存至少50天the size of a small Van.所以面临着这么多问题So, in the face of overwhelming odds,任务日我只有一个选择I'm left with only one option.我得大展科学神威了I'm gonna have to science the shit out of this.任务日任务日好成功了Okay, so, success.我借助一号♥探测车将电池寿命延长了一倍I have doubled my battery life by scavenging Rover 1.但如果我开了暖气But if I use the heater...每天暖气就要消耗一半的电池I will burn through half my battery every day.如果不用暖气我就会If I do not use my heater, I will be...因为热量不足被慢慢冻死slowly killed by the laws of thermodynamics.我很想立即就解决这个问题I would love to solve this problem right now可不幸的是but unfortunately...任务日我的蛋蛋都快冻掉了My balls are frozen.不行我认输我认输I can't. I'm calling it. I'm calling it.任务日好消息我可能有办法Good news, I may have a solution解决供暖问题了to my heating problem.坏消息就是我得把Bad news, it involves me digging up放射性同位素热电机挖出来the radioisotope thermoelectric generator.如果我的记得没错的话Now, if I remember my training correctly,航♥空♥训练有一课叫做one of the lessons was titled..."千万别把放射性物质挖出来马克""Don't dig up the big box of plutonium, Mark."放射性同位素热电机对航♥天♥器是好东西I get it. RTGs are good for spacecraft,但要是泄漏了but if they rupture around humans...附近的人类就连渣都不剩no more humans.所以一着陆我们就把它埋了起来Which is why we buried it when we arrived.插上这面旗And planted that flag...也就没有人会笨到So we would never be stupid enough去靠近它to accidentally go near it again.但只要我没把它弄坏就行But as long as I don't break it...我刚刚差点就大声喊出I almost just said一切都会好起来的"Everything will be fine" out loud.重点是我现在一点都不冷了Look, the point is, I'm not cold anymore.当然了我也可以想到我之所以不冷了And sure, I could choose to think about the fact that I'm warm...是因为我正在受到后面放射性同位素热电机的辐射Because I have a decaying radioactive isotope riding right behind me...现在我还有更大的问题But right now, I got bigger problems on my hands.任务日我翻遍了露易丝指挥官I have scoured every single data file硬盘上所有的文件夹on commander Lewis' personal drive.这绝对是最不像迪斯科的歌♥This is officially the least disco song she owns.♪Lookin' for some hot stuff baby this evenin'♪♪I need some hot stuff baby tonight♪♪I want some hot stuff baby this evenin'♪♪Gotta have some hot stuff♪♪Gotta have some lovin' tonight♪♪I need hot stuff♪♪I want some hot stuff♪♪I need hot stuff♪-这位-沃特尼这是要去哪里- Yeah. - Where is Watney going?我们认为他是准备长途旅行We believe that he's preparing for a journey.他一直在进行增量测试He's been conducting incremental tests...每次驾驶二号♥探测车Taking the Rover 2 out for longer走得一次比一次远and longer trips each time.要去哪里他为什么要离开相对安全的居住舱呢To what end? Why would he leave the relative safety of the hab?我们认为他计划到Well, we think that he plans to travel战神四号♥的着陆点to the Ares 4 launch site...以便和我们取得联♥系♥In order to make contact with us,但这是一次很危险的赌博but it would be a dangerous gamble.但如果我们能和他取得联♥系♥But if we could talk to him,我们会告诉他原地不动we would tell him to stay put...相信我们一定会竭尽全力And to trust that we are doing everything in our power把他活着带回家to bring him home alive.非常感谢Thank you very much.别说"活着带回来"这种话文森特Don't say "Bring him home alive," Vincent.你又不是不知道这种记者会太难了You know what? These interviews aren't easy.原谅我想说点积极向上的话So god forbid I try to say something proactive and positive.安妮Annie.再也不让文森特上电视遵命No more Vincent on TV. Copy that.76公里我看的没错吧76 kilometers. Am I reading that right?在问我吗Are you asking me?是啊I am.是的长官Yes, sir.马克从居住舱出发开了两小时Mark drove two hours straightaway from the hab...进行了短期的舱外活动后又开了两小时Did a short EVA and then drove for another two.我们认为短暂的舱外活动是为了换电池We think the EVA was to change batteries.他没有装氧合器He didn't load up the oxygenator和净水回收机吗or the water reclaimer?每行驶41小时都会有17分钟的空白。

活动星系核VLBI 观测的新进展蒋栋荣(1,2)(1.中国科学院上海天文台,上海200030;2.国家天文台,北京100012)摘要:介绍了活动星系核(AGN )的VLBI 观测的新近展,特别关注其中心结构和低光度的活动星系核。

主要目的是强调VLBI 观测在该领域的重要性。

关键词:VLBI 技术;活动星系核中图分类号:P 157.6　文献标识码:A 1001-7526(2003)01-0037-04Progress in the VLBI observation of AG NsJI ANG Dong -rong 1,2(1.Shanghai Astronomical Observatory ,The Chinese Academy of Sciences ,Shanghai 200030,China ;2.National Astronomical Observatories ,The Chinese Academy of Sciences ,Beijing 100012,China .E -mail :djiang @center .s hao .ac .cn )A bstract :This paper r eports some recent pr ogresses in the VLBI observation of the AGNs ,specially those in the investigations about the central structure of the AGNs and the low luminosity AGNs .The main goal is to sho w the importance of the VLBI observations in this field .Key words :VLBI ;active galactic nuclei1　INTRODUC TIONAs the improvement of the sensitivity and angular resolution ,the Ver y Long Baseline Interferometry (VLBI )has become a po werful tool to pr obe the most compact structur e in the various astronomical objects ,including the active galactic nuclei (AGN ),the micr oquasars in the Milk Way ,the astronomical masers and radio stars .The VLBI observations of the radio emission in the radio -loud AGNs have made many contributions to the development of the relativistic jet model and the standard model of AGNs .The one -side pc scale jet and the apparent superluminal motion (SLM )of the components in the compact structure in the radio -loud AGNs suggested that the bulk motion of the pc scale jet is 2003No .1 云　南　天　文　台　台　刊Publications of Yunnan Observatory 2003年第1期Foundati on item :This work was funded by the NKBR SF (G1999075403)收稿日期:2002-10-08relativistic and the relativistic beaming in these objects is important .The alignment between the pc scale jet and the kpc scale emission gives the evidence that the central engine supports the ener gy of the radio emission on the large scale .All these makes the radio jet as the one of the main activities in the central engine of the AGNs .Since the ne w progr ess in the field is so plentiful ,in this paper we report only some new results form the literature ,specially those on the investigations about the central structure of the AGNs and the lo w luminosity AGNs .The main goal is to show the importance of the VLBI observations in this field .2　SOME NEW RESULTS2.1　central Black holeThe spectral line VLBI observations at 22GHz in the central nucleus of the NGC 4258r evealed that the H 2O maser spots are distributed on a thin sub -pc scale disk ,the high velocity maser featur es have a Keplerian distribution of the velocities ,which indicate the pr esence of a mass of3.6×107solar masses in a region less than 0.13pc ,the central object is very possible aSuppermassive black hole .(Miyoshi et al .1995,Greenhill et al .1995)[1,2].2.2　jet formationThe global VLBI high resolution image of M87at 43GHz sho ws a broad jet near the center ,the jet opening angle decreases as the distance within 1pc from the VLBI core .Apparently ,the jetcollimation is on scales more than 0.04pc (corresponding to 100r s )(Junor et al .1999)[3].Thismay be the first time that the VLBI observation can probe the process on the jet for mation and collimation in the AGNs .2.3　disk and torusIn the inner regions of the disks in AGNs ,a lar ge fraction of the gas must be ionized by the central engine ,and this results in the free -free absorption of the radio continuum emission .When the orientation of the pc scale jet is near the sky plane ,the jet and counter -jet are detected with the VLBI ,then the structure of the accretion disk can be probed through the free -free absorption of the synchrotron emission .The best example is the near FRI galaxy NGC4161,the multi -band VLBI investigation suggested that the average electron number density in the inner 0.1pc is 103-108c m -3and the mass of the ionized gas in the disk is 101-103solar masses (Jones et al .2000)[4].The neutral gas in the circumnuclear torus results in the 21cm HI absorption line ,ther efore the VLBI observation of the broad absorption line toward the central r egion will provide the important infor mation about the distribution and the kinematics of the gas in the torus .The several radio galaxies and Compact Symmetric Objects (CSOs )have been probed by the HI line VLBI .In PKS 2322-123,the absorption lines are redshifted with respect to the systemic velocity ,and thissuggested that ther e are inward strea ming motions in this atomic torus (Taylor et al .1999)[5].38 云　南　天　文　台　台　刊 2003年2.4　Space VLBIThe VSOP is the first space VLBI mission ,together with the ground telescopes that pr oduces a lot of high resolution images of the jets in the AGNs .The one of the results in the survey project shown that there is a significant fraction of sources ,of which the brightness temperature in thesource -frame is greater than 1012K (Lovell et al .2000)[6].The radio emission acr oss the jet inthe VSOP image of the 3C273was r esolved ,a double helix structure was found (Lobanov and Zensus 2001)[7].The statistic results of the PR sample provided more evidence of the relativisticbea m in these sources (Lister et al .2001)[8].2.5　Lo w luminosity AGNsThe difference between the radio -loud and the radio -quite AGNs is still an open question .The infor mation about the compact structure of the radio emission in the low luminosity AGNs is very important for understanding the properties of the radio emission and the role of the relativistic bea ming effect in the unified scheme .Thanks to the high sensitivity of the current VLBI observation ,it is possible to study the structure of the radio emission on the pc scale .A apparent transversal velocity of 2.7c was detected in the pc scale jet of the giant ,lo w -power radio galaxyB21144+35(Giovannini et al .1999)[9].In the VLBI monitoring of the Seyfert 1galaxy ⅢZw 2,the inner jet suddenly expanded during about a few months with a speed about 1.2c ,and it is the first detected SL M in the inner radio jet of the spiral galaxy (Br unthaler et al .2000)[10].These r esults suggested that the inner jets in the low luminosity AGNs is also r elativistic ,at least in some sources .The VLBA observation of a sample of nearby LINER galaxies revealed high brightness temperature radio cores in their nuclei ,the average T b is about 1.0×108K .In the brightest cores the VLB A resolved the radio emission into jet -like structures (Falc ke et al .2000)[11].European VLBI Net w or k (EVN )1.6GHz observation of the Hubble Deep Field region detected three radiosources at about 210μJy /bea m detection level (Garrett et al .2001)[12].The mor e systematic study of the radio structur e on the pc scale in the lo w luminosity AGNs is certainly needed for well understanding the differ ence between the radio -loud and radio -quite AGNs and the connection between the AGNs and the starburst system .3　THE FUTURE IN ASIAIn East -Asia ,the VLBI at high frequencies will be developed ,including the Japanese pr ojects ,VLBI E xploration of Radio Astrometry (VERA )and the secondary space VLBI mission VSOP -2,and Korean VLBI Network (KVN ).The VLBI community in China hase to think the possibility for jointing the regional c ooperation in this field .39第1期 蒋栋荣:活动星系核VLBI 观测的新进展 References[1]　Miyoshi M ,Moran J M ,Herrnstein J R ,et al .Natur e ,1995,373:127.[2]　Greenhill L J ,Jiang D R ,Moran J M ,et al .ApJ .,1995,440:619.[3]　Junor W ,Biretta J A ,Livio M .Natur e ,1999,401:891.[4]　Jones D L ,Wehrle A E ,Meier D L ,et al .ApJ .,2000,534:165.[5]　Taylor G B ,OD ′ea C P ,Peck A B ,et al .ApJ .,1999,512:L27.[6]　Lovell J E J ,Horiuchi S ,Moellenbrock G ,et al .In :H Hiraba yashi et al ,eds .Astrophysical Phenomena Revealed by Space VLBI ,Kanaga wa :ISAS ,2000,183.[7]　Lobanov A P ,Zensus J A .Sci .,2001,294:128.[8]　Lister M L ,Tingay S J ,Preston R A .ApJ .,2001,554:964.[9]　Giovannini G ,Taylor G B ,Arbizzani E ,et al .ApJ .,1999,522:101.[10]　Brunthaler A ,Falcke H ,Bower G C ,et al .A &A .,2000,357:L45.[11]　Falcke H ,Nagar N M ,Wilson A S ,et al .ApJ .,2000,542:197.[12]　Garrett M A ,Muxlo w T W B ,Garrington S T ,et al .A &A .,2001,L5.40 云　南　天　文　台　台　刊 2003年。

时隔十多年我科学家再次听见一颗黑洞的“心跳”
作者：
来源：《科学大观园》2020年第13期
十几年前，天文学家首次发现来自一个超大质量黑洞的“心跳”——X射线准周期振荡信号。

十几年后，当天文学家再次有机会观测这个黑洞时，发现这个信号仍在持续。

这项研究工作由中国科学院国家天文台研究员金驰川主导，研究结果近日已发表于《英国皇家天文学会月刊》。

这个特殊的黑洞被命名为RE J1034+396，是一个距离地球6亿光年的超大質量黑洞。

2007年，科学家们首次发现这个黑洞的X射线辐射具有一小时左右的周期性振荡信号。

2011年，由于该黑洞的视线方向离太阳太近，对其“心跳”信号的监测也就停止了。

直到2018年，科学家们有机会再次对这个黑洞开展观测。

金驰川研究团队通过使用XMM-牛顿卫星、“核光谱望远镜阵列（NuSTAR）”卫星和“雨燕（Swift）”卫星，对RE
J1034+396开展联合观测，并最终确认其X射线振荡信号仍然存在，而且比以前更强了。

这是目前观测到的持续时间最长的超大质量黑洞“心跳”信号。

◎来源|科技日报。