求教： cat number 是什么意思？ - 外贸英语 -
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& 求教： cat number 是什么意思？
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求教： cat number 是什么意思？
cat number 是什么意思？
[ 本帖最后由 starzhang430 于
09:58 编辑 ]
(服不外贸人)
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”商品目录编码“ 的意思吧！不知道对不！呵呵！！
(Night Owl )
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来自 Shanghai
打错了（C和V在键盘上的位置紧挨着哦~）~~应该是VAT number~~增值税发票号~~~
YOYO(尤同学)滴爱徒2号@^@
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来自 湖南--东莞
呵呵 cat number没看过是什么哦 ----像LS说的VAT number就知道 嘿嘿---
滚来滚去的混混
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来自 Fuzhou Fujian
知识又多了一点。
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回复 #2 royren 的帖子
catalogue number应该是吧
当前时区 GMT+8, 现在时间是
Powered by D1scuz! && 2001-54XMM-Newton observations of the Lockman Hole X-ray source catalogue and number counts
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54XMM-Newton observations of the Lockman Hole X-ray source catalogue and number counts
Astronomy&Astrophysi；cESO2008??；XMM-Newtonobservationsof；catalogueandnumbercounts；H.Brunner1,N.Cappelluti1；arXiv:[astro-；1234；Max-Planck-Institutf¨ure；InstituteofAst
Astronomy&Astrophysicsmanuscriptno.lhpaperBn2February2,2008cESO2008??XMM-NewtonobservationsoftheLockmanHole:X-raysourcecatalogueandnumbercounts?H.Brunner1,N.Cappelluti1,G.Hasinger1,X.Barcons2,A.C.Fabian3,V.Mainieri1,4andG.Szokoly1arXiv:
[astro-ph]
29 Nov 20071234Max-Planck-Institutf¨urextraterrestrischePhysik,85478Garching,GermanyInstitutodeF′?sicadeCantabria(CSIC-UC),39005Santander,SpainInstituteofAstronomy,UniversityofCambridge,MadingleyRoad,Cambridge,CB30HAESO,Karl-Schwarschild-Strasse2,85748Garching,GermanyRacceptedABSTRACTContext.TheLockmanHole?eldrepresentstheskyareaoflowestGalacticline-of-sightcolumndensityNH=5.7×1019cm?2.ItwasobservedbytheXMM-NewtonX-rayobservatoryin18pointingsforatotalof1.16Msec(rawEPICpnobservingtime)constitutingthedeepestXMM-Newtonexposuresofar.Aftertheremovaloftimeintervalswithhighparticlebackground,the?nale?ectiveexposurewas637ks.Aims.WepresentacatalogueoftheX-raysourcesdetectedinthecentral0.196deg2ofthe?eldanddiscussthederivednumbercountsandX-raycolours.Methods.TheanalysiswasperformedusingtheXMM-SASdataanalysispackageversion6.0.ThedetectionsensitivityandfractionofspuriousdetectionswascalibratedusingMonteCarlosimulations.Results.Inthe0.5C2.0keVband,asensitivitylimit(de?nedasthefaintestdetectablesource)of1.9×10?16ergcm?2s?1wasreached.The2.0C10.0keVbandand5.0C10.0keVbandsensitivitylimitswere9×10?16ergcm?2s?1and1.8×10?15ergcm?2s?1,respectively.Atotalof409sourcesaboveadetectionlikelihoodof10(3.9sigma)werefoundwithinaradiusof15′o?the?eldcentre,ofwhich340,266,and98sourcesweredetectedinthesoft,hard,andveryhardbands,respectively.ThenumbercountsineachenergybandareincloseagreementwithresultsfromprevioussurveysandwiththesynthesismodelsoftheX-raybackground.A6%ofCompton-thicksourcecandidateshavebeenselectedfromtheX-raycolour-colourdiagram.ThisfractionisconsistentwiththemostrecentpredictionsofX-raybackgroundpopulationsynthesismodelsatour?uxlimits.Wealsoestimated,forthe?rsttime,thelogN-logSrelationforCompton-thickAGN.Keywords.surveyCgalaxies:activeCgalaxies:quasars:generalCX-ray:galaxiesCX-rays:general1.IntroductionDuetoitsextremelylowlineofsightcolumndensityofNH=5.7×1019cm?2,theLockmanHole?eldisoneofthemainextragalacticdeep-surveytargetareasofrecentX-rayobserva-tories.ThechoiceofalowNH?eldontheonehandoptimizesthesoft-bandsensitivitycomparedto?eldswithhigherNH.Anevenmoreimportantaspectisthatformanysourceswecande-terminespectratothelowestpossibleenergiesandthusgetabetterhandleonthecontinuumandintrinsicabsorption.The?eldwasobservedforatotalof1.1Msec,bytheROSATHRIdetector,reachingasensitivitylimitof1.2?10?15ergcm?2s?1inthe0.5C2.0keVband,forthe?rsttimeresolvingthemajorityofthesoftX-raybackgroundintodiscretesources(Hasingeretal.1998).TheLockmanHolewasalsothetar-getofthedeepestobservationsconductedbytheXMM-Newtonobservatory,considerablyimprovingthesensitivitylimitinthesoftbandandextendingthesurveyintothehardX-raybanduptoanenergyof10keV.AlthoughthesensitivitylimitoftheXMM-NewtonLockmanHolesurveydoesnotreachthesensi-tivityofthedeepestsurveysperformedbytheChandraobserva-tory(i.e.theChandradeep?eldNorthandSouth,Baueretal.2H.Brunneretal.:XMM-NewtonobservationsoftheLockmanHolebinedall-EPICvignetting-correctedsoftbandexposuremapof18XMM-NewtonpointingsontheLockmanHole?eld.Theblackcirclerepresentstheregionof15′radiusunderinvestigation.2.ObservationsTheLockmanHole?eldwasobservedbyXMM-Newtonin18individualpointingsdistributedoveratwoandahalfyeartimeperiodfromApril2000toDecember2002.Twelvepointingswerecentredattheapproximate?eldcentrecoordinates+10h52m43s,57?28′48′′(J2000),withsmallo?sets～15′′toachieveanadequatecoverageoftheskyareafallingintochipgapsinindividualobservations.Theremainingpointingswerespreadoutoverabout30′inrightascension,thuscoveringasomewhatwiderareaatintermediateexposurelevels.Thepatternoftheob-servationsisshowninthevignettingcorrectedexposuremapofFig.1(seenextsection).ThetotalXMM-Newtonexposuretimespentonthe?eldwas1.30Msec(EPICMOSEPICpndetector:1.16Msec).Afterremovaloftimesa?ectedbyback-ground?ares765ks(EPICMOSEPICpndetector:637ksec)areleftwhicharesuitableforscienti?canalysis.Ifthelossofsensitivityatlargeo?-axisanglesduetovignettingisconsidered,theaverageexposuretimeisreducedto557.6ks(weightedaverageofMOSandpndetectors).Thispaperad-dressestheskyareawithin15′ofthe?eldcentrewheretheex-posureexceeds185ks.Table1liststhepointingdirectionsandexposuretimes.ThetwelvecentralpointingsandEastandWesto?setpointingsaremarkedbyC,E,andW,respectively.3.DatareductionEventcalibrationwasperformedbyuniformlyprocessingall18datasetsusingtheXMM-SAS6.0softwarepackage1.Timesaf-fectedbybackground?areswerescreenedoutbyusinga3σX-rayeventshittingthedetectorduringread-outresultinginalossofpositionalinformationintheread-outdirection.2H.Brunneretal.:XMM-NewtonobservationsoftheLockmanHole3Table1.PointingdirectionsandexposuretimesIDbRA(J2000)DEC?′′′hhmmsso?setc′MOSpndexposuretimes[ksec]abXMM-Newtonorbitnumber(revolution)cXMM-NewtonobservationIDdo?setfrom?eldcentre+10h52m43s,57?28′48′′eraw(after?arescreening)central(C)pointings,East(E),andWest(W)o?setpointingsinga2power-lawspectralindexofΓ=2.0andN.Thecombinedall-EPICexposuremapofH=5.7×1019cm?the18obser-vationsoftheLockmanHole?eldisdisplayedinFig.1.Thedisplayedexposuresincludecorrectionsfortelescopevignetting(heredisplayedforthesoftband).Thecirclemarksthe15′ra-diusareadiscussedinthispaper.Thelargevarietyofspectralpropertiesofthesourcepopula-tionisdemonstratedinthefalsecolourimageofthe?eld(Fig.2),displayingexposurecorrectedandbackgroundsubtractedcountratesofthesoft,hard,andveryhardenergybandsinthecoloursred,green,andblue,respectively.Whilethedistributionofspectraltypesasindicatedbythecolourimagesappearswide,Mateosetal.(2005)andMainierietal.(2002and2007)intheLockmanHoleandHasingeretal.(2007)intheCOSMOSFieldshowedthatthespectraoftheX-raysourceshaveanaveragephotonindex&Γ&～2.Thechoiceofmodelingtheaveragespectrumwithapower-lawwithspectralindex&Γ&=2andNH=5.7×10?19cm?2forestimatingthe?uxesisthereforecon-sistentwithadetailedspectralanalysis.TheconsiderablefractionofblueandgreenobjectsmainlyrepresentsthepopulationofabsorbedAGNinthe?eld.Aquan-titativeanalysisoftheX-raycoloursbasedonthehardnessra-tiosdeterminedfromthesourcecountratesineachenergybandispresentedinsection4.4.Alsonotetheclearlyvisiblepopu-lationofextendedobjects,includingthedistantdoubleclusterRXJ5(Hashimotoetal.2004and2005)intheup-perleftpartoftheimage(sourcenumbers461and472;Fig.3,tables3and4).Thesourceparametersofthedetectedextendedobjectsarealsodiscussedinsection4.4.4.Dataanalysis4.1.Maximumlikelihoodmulti-stagesourcedetectionSourcedetectionwasperformedsimultaneouslyonthesoft,hard,andveryhardbandimagesusingtheeboxdetectandemlde-tecttasksoftheXMM-SASdataanalysispackage.Inthefollow-ingsectionwebrie?ydescribetheXMM-SASsourseetheXMM-SASdocumentation1foradditionalde-tails.Thesourcedetectionprocedureconsistsofthreeconsecu-tivedetectionsteps.Aninitialsourcelistiscreatedbyrunningaslidingboxdetectionalgorithm(XMM-SAStaskeboxdetect)withdetectionboxsizes5×5,10×10,and20×20pixels(15′′×15′′,30′′×30′′,and60′′×60′′),wherethelocalback-groundisestimatedfrompixelsadjacenttothedetectionbox.Theglobalbackgroundisdeterminedby?ttingacombinationofvignettedandnon-vignettedbackgroundcomponentstothesourcefreeregions(asdeterminedfromtheinitialsourcelist).Theeboxdetectdetectiontaskisthenrerunusingtheglobalbackgroundmodelforimproveddetectionsensitivity,creatingalistofsourcecandidatesdowntoalowstatisticalsigni?cancelevel(～2σ).Thislistisfedintotheemldetecttaskwhichper-formsaMaximumLikelihood?tofthedistributionofsourcecounts(basedontheCashC-statisticsapproach,Cash1979),us-ingapointspreadfunctionmodelobtainedfromraytracingcal-culations(mediumaccuracymodelfromtheXMM-Newtoncal-ibrationdatabase),creatingthe?nalsourcelistofbest-?tsourcepositionsand?uxes.The?tisperformedsimultaneouslyinallenergybandsbysummingthelikelihoodcontributionsofeachband.Sourcesexceedingthedetectionlikelihoodthresholdinthefullbandarethecatalogueisthusfullbandselected,i.e.,italsoincludesveryweaksourceswhichdonotexceedthedetectionthresholdinanyoftheindividualbands.Alternatively,itispossiblethataweaksourcewhichslightlyex-4H.Brunneretal.:XMM-NewtonobservationsoftheLockmanHoleFig.2.Exposurecorrectedandbackgroundsubtractedfalsecolourimage.Thecoloursred,green,andbluecodethe0.5C2.0keV,2.0C4.5keV,and4.5C10keV?uxes,respectively.Northisatthetop,Eastistotheleft.Theimageiscentredon10h52m43s,57?28′48′′(J2000)andthe?eldsizeisapproximately30′×30′.ceedsthedetectionthresholdinoneenergybandandisnotde-tectedintheotherbandsmaybeexcludedfromthecataloguebecauseitdoesnotreachthedetectionthresholdinthetotalband.Adetectionlikelihoodthresholdof10wasusedforinclu-sionofdetectedobjectsintothesourcecataloguewhileobjectswithdetectionlikelihoodsabove6wereconsideredfordeter-miningthenumbercounts(seedetailsinsection4.3and4.4).TheC-statisticsapproachcanalsobeusedtocalculatethelike-lihoodofthesourceextent.Thebest-?tparametersdeterminedforeachdetectedsourcethusarethesourceposition,?uxesineachenergybandand,optionally,thesourceextent(expressedasthecoreradiusofaKingpro?le).Inthelattercase,foreachsource,thedistributionofsourcecountsismodelledbynumeri-callyfoldingthepointspreadfunctionwithaKingpro?le.Thesigni?canceofdetectioninthetotalbandandineachindividualenergybandisexpressedintheformofadetectionlikelihood,L,normalizedtotwodegreesoffreedom,obeyingtherelation-shipL=?ln(p),wherepistheprobabilitythattheobservedsourcecountsareduetoPoissonian?uctuations3.Inprincipletheexpectednumberofspurioussourcesisthusde?nedasthenumberofindependenttrials×pwithp=e?L.Thenumberoftrialscanbeapproximatedbythenumberofpointspreadfunc-tionsizedbeamsinthe?eld.ThisrelationshipisdisplayedasastraigthlineinFig.4(seesection4.2fordetails).However,duetothecomplexnatureofthemulti-stepdetectionprocedure,thisrelationshipcanonlyberegardedasaroughapproximationwhichneedstobecalibratedbyMonteCarlosimulations(seesection4.2).AdetaileddescriptionoftheMaximumLikelihoodsourcedetectionmethodcanalsobefoundinCappellutietal.(2007).H.Brunneretal.:XMM-NewtonobservationsoftheLockmanHole5Fig.3.Backgroundsubtractedfullbandimage.Detectedsourcesaremarkedbytheir1σpositionalerrorcircleandsourcenumber.FieldsizeandorientationasinFig.2.4.2.MonteCarlosimulationsThebehaviourofthedetectionprocedurewasveri?edbyMonteCarlosimulations.Wecreated50simulated?eldsinthesoft,hard,andveryhardenergyband,eachwiththesameskyex-posuredistributionandbackgroundlevel,withrandomsourcepopulationsfollowingastandardlogN-logSdistributionandthesamespectralmodelasassumedforcomputingtheexposuremaps.4Inordertoproperlymodelthesourceconfusion,sourcesweresimulateddowntoasoft?uxof3×10?19ergcm?2s?1.Thepointspreadfunctionofthesimulatedsourceswascon-structedfromray-tracingderivedpointspreadfunctionmapsavailableintheXMM-Newtoncalibrationdatabaseandbyas-包含各类专业文献、专业论文、各类资格考试、文学作品欣赏、外语学习资料、中学教育、高等教育、54XMM-Newton observations of the Lockman Hole X-ray source catalogue and number counts等内容。　NW&NT catalogue 2012_百度文库
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