homework – and other housekeeping maersthuard/astr288c/lecture3-notes.pdf · 4:30. •...
TRANSCRIPT
Homework–andotherhousekeepingma4ers
• Homeworkisdueat3:30PMWednesday(oftheweekfollowingaclass)insteadofMonday.
• TurnintotheAstronomyMailRoom(CSS1204)thatclosesat4:30.
• AlternaDvely,turnintousinourofficeorinclass.• HomeworkwillbereturnedthefollowingMonday(two
weeksaIeritishandedout),solatehomework(witha20%/daypenalty)mustbeinbeforeclassonthatday.
• ThelowestHWscorewillbedropped.• HWsoluDonswillbepostedonthewebsiteaIerallofthe
assignmentsarecompleted.• ThisinformaDonisontheupdatedsyllabus–seee‐mail
a4achment,classwebsite.• Thewebsitealsohasalllecturenotes,labs,andassignments.
HighEnergyDatabasesandCatalogs
AccessingPublicDataontheWeb
• Sources:facility/missionsites,dedicatedarchives,linksfromelectronicjournalarDcles
• Content:rawand/orprocesseddata,auxiliarydata(e.g.,calibraDon),reducDonandanalysistools,dataproducts(images,spectra),catalogs
AccessingPublicDataontheWeb
Usage:(1) ReaddocumentaDon(manuals,helpfiles,
tutorials).
(2)IdenDfytheobject(s)orregion(s)ofinterest.
(3)IDthetypeofdatarequired(including
wavelengthregime).
(4)Downloadwhatyouneed.
NASA/IPACExtragalac<cDatabase(NED)
NEDisbuildaroundamasterlistofextragalac9cobjectssearchablebynameorregion.Collectedare…
• Sourcenames• PosiDonsandtheirCoordinates• RedshiIsandradialvelociDes• OpDcaldiametersandmagnitudes• Imagesfrom(ground‐based)opDcalandIRall‐skysurveys• Spectra• Bibliographicreferences
NEDisagoodstarDngpointifoneisinterestedinaparDcularextragalacDcobject.
NASA/IPACExtragalac<cDatabase(NED)
NEDhasfivebroadsecDons• Objects• Data• Literature• Tools• Info–checkouttheintro,FAQ,overview
NASA/IPACExtragalac<cDatabase(NED)
InaddiDonto“staDc”data,NEDalsoprovides• Calculatorsandothertools.• CoordinatetransformaDons• ExDncDoncalculator• Cosmologycalculators• Plodngtools• Batchjobs• Muchmore…
Re‐analysis‐‐newmethods,calibraDonNewfocus‐‐• partofauniformsample• lookforsomenewphenomenondiscoveredelsewhere• lookforvariabilitycomparedtodataelsewhen• lookforcounterpartstosourcesatotherwavelengths
Data“Archives”• SiteswheredataarestoredaresomeDmescalledarchives.• OIen,aIersomeproprietaryperiod(say,oneyear)thedatabecomepubliclyaccessible,andmaybedownloaded.
Whyanalyzearchivaldata?
QuesDonstoConsider
• WhatdocumentaDonisavailable?• WhatfilesdoIneed?• Isthedatapreprocessed?• Isthedatacalibrated?• Whatformatisthedatain?• WhatsoIwaredoIneedtousethedata?• WhodoIacknowledgewhenIpublishthedata?
HighEnergyAstrophysicsScienceArchiveResearchCenter(HEASARC)
AccesstootherNASAarchives,suchasNED
TheinterfacetotheHEASARCarchiveIscalledBrowse.
OnecommonlysearchesbyobjectnameorposiDon.Onemayspecifyasearchradius,aswellasthemissionsandcatalogstobequeried.
Ifnomissionorcatalogisselected,onegetsalistofallofthepossibleselecDonswithentrieslocatedontheskywithinthesearchradius.Fromamongthese,wechoosetoviewthetableofobservaDonsfromthe X‐rayObservatory.
Thisreturnsonetable‐‐themasterdatabaseofallcompletedandplannedChandraobservaDons‐‐inthisinstance,whichleadsusto…
…thelistofobservaDons,fromwhichweselectthelongestandmostrecentlyarchivedobservaDon
Theseareavailable
WecannowpreviewthedataandretrievetherequestedFITSfiles….
…andcreateasingletarfilecontainingallofthesefiles.
Thetarfilewiththerequesteddataisnowavailablefordownloading.
loew%tar‐xvfw3browse‐172321.tar9517/primary/acisf09517N001_cntr_img2.fits.gzloew%mv9517/primary/acisf09517N001_cntr_img2.fits.gz.loew%ls9517primaryloew%ls9517/primaryloew%rm‐r‐i9517examinefilesindirectory9517?yexaminefilesindirectory9517/primary?yremove9517/primary?yremove9517?Yloew%ls9517ls:9517:Nosuchfileordirectoryloew%rm‐iw3browse‐172321.tarremovew3browse‐172321.tar?yloew%gunzipacisf09517N001_cntr_img2.fits.gzloew%ls*.fitsacisf09517N001_cntr_img2.fitsds9acisf09517N001_cntr_img2.fits&
Inthedirectorywherethedatawasdownloaded(here``loew’’),unpackthetarfile.Movetheimagefitsfilebacktotheoriginaldirectoryanduncompressit,dele@ngunneededsubdirectories.(Alterna@vely,cd9517/primary,andworkinthatdirectory).
StepsleadingfromthedownloadtoopeningtheimageFITSfilewithds9‐‐acombinaDonofUNIXpracDceand“Ddying”up.
OverlayingX‐raycontoursonanop@calimage–step‐by‐step
See,also,h4p://cxc.harvard.edu/ciao/threads/ds9/.(whichhasalinktods9manuals)
ChandraX‐rayimageoftheNGC5813ellipDcalgalaxy
zoomtofit
rescalecolorsusingzscale
changecolor
smooth[analysis–>smoothparameters]
rescalecolors
x‐raycontours[analysis–>contourparameters]savetheseinafile[analysis–>contourparameters–>file–>savecontours]
LoadDSSopDcalimage[analysis–>imageservers–>STSCI‐DSSI/II](automaDcallyDled)
rescalecolorsinopDcalimage
WCS‐alignimages[Frame–>MatchFrames–>WCS]
rescalecolorsinopDcalimage
overlayopDcalcontoursonopDcalimage
clearopDcalcontours
overlayx‐raycontoursonopDcalimage[analysis–>contourparameters–>file–>loadcontours]
AQuickLookatRegionsandCatalogsinDS9
TheframewiththesmoothedX‐rayimage,contourscleared.
Placeacircle(thedefaultregionshape)aroundapointsource.Adjustthecenterandradius(to10’’),andexpresstheseinsexagesimalWCScoordinates[region–>getinforma9on].
savetheseinafile[region–>saveregions],andthenremovefromtheimage[region–>deleteallregions]
Reloadthesavedregion[region–>loadregions]
OverplotsourceposiDonsretrievedfromtheFIRSTradiosurvey,usingbluecrosspointsymbols[analysis–>catalogs–>radio–>firstsurvey]