J/ApJ/766/88ivo://CDS.VizieR/J/ApJ/766/88doi:10.26093/cds/vizier.17660088CDSBurke M.J.Raychaudhury S.Kraft R.P.Maccarone T.J.Brassington N.J.,Hardcastle M.J.Kainulainen J.Woodley K.A.Goodger J.L.Sivakoff G.R.,Forman W.R.Jones C.Murray S.S.Birkinshaw M.Croston J.H.,Evans D.A.Gilfanov M.Jordan A.Sarazin C.L.Voss R.Worrall D.M.,Zhang Z.2018-01-30T07:18:08Z2014-12-12T07:15:41ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frx-ray-binary-starsgalaxiesWe present a spectral investigation of X-ray binaries (XBs) in NGC 5128 (Cen A), using six 100ks Chandra observations taken over two months in 2007. We divide our sample into thermally and non-thermally dominated states based on the behavior of the fitted absorption column N_H_, and present the spectral parameters of sources with L_x_>~2x10^37^erg/s. The majority of sources are consistent with being neutron star low-mass X-ray binaries (NS LMXBs) and we identify three transient black hole (BH) LMXB candidates coincident with the dust lane, which is the remnant of a small late-type galaxy. Our results also provide tentative support for the apparent "gap" in the mass distribution of compact objects between ~2-5M_{sun}_. We propose that BH LMXBs are preferentially found in the dust lane, and suggest this is because of the younger stellar population. The majority (~70%-80%) of potential Roche lobe filling donors in the Cen A halo are >~12Gyr old, while BH LMXBs require donors >~1M_{sun}_ to produce the observed peak luminosities. This requirement for more massive donors may also explain recent results that claim a steepening of the X-ray luminosity function with age at L_x_>=5x10^38^erg/s for the XB population of early-type galaxies; for older stellar populations, there are fewer stars >~1M_{sun}_, which are required to form the more luminous sources.2013ApJ...766...88Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/766/88CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/chandra : The Chandra Archive Log (CXC, 1999-2014)J/AJ/143/84 : New candidate globular clusters in NGC 5128 (Harris+, 2012)J/A+A/533/A33 : LMXBs detected in nearby galaxies (Zhang+, 2011)J/ApJS/192/10 : Chandra ACIS survey in 383 nearby galaxies. I. (Liu, 2011)J/MNRAS/401/1965 : Globular clusters in M104 (Harris+, 2010)J/ApJ/682/199 : Globulars with X-ray sources in NGC 5128 (Woodley+, 2008)J/ApJ/654/186 : VI photometry of Cepheids in NGC 5128 (Ferrarese+, 2007)J/A+A/447/71 : CHANDRA X-ray point sources in Cen A (NGC 5128) (Voss+, 2006)J/ApJ/602/231 : Chandra X-ray point sources in nearby galaxies (Colbert+, 2004)J/ApJ/600/716 : NGC 5128 Chandra X-ray point sources (Minniti+, 2004)J/ApJ/560/675 : Chandra X-ray point sources in Cen A (Kraft+, 2001)http://cxc.harvard.edu/ : Chandra X-Ray Observatory (CXC) home pagehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/766/88https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/766/88http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/766/88https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/766/88https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/766/88http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/766/88GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/766/88/table1 (Basic Source Properties)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/766/88/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/766/88/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/766/88/table1?GETtext/xml+votable180.050000true201.3260417-43.05136110.0055555555555555566/43262https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/766/88?format=asciiOpticaldefaultJ/ApJ/766/88/table1Basic Source Propertiesf_C7797Flag on C7797 (1)meta.codecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDSource identifier (S1 to S61)meta.id;meta.maincharprimaryn_IDAdditional flag (1)meta.notecharRAJ2000[13] Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000[42/43] Degree of Declination (J2000)pos.eq.dec;meta.mainspNumber of different spectral fits (tables 2 and 3)meta.ref.urlintnullableC7797? Net 0.5-8 keV counts in ObsID 7797ctphot.count;em.X-rayintnullablee_C7797? Lower uncertainty limit on C7797ctstat.errorintnullableE_C7797? Upper uncertainty limit on C7797ctstat.error;stat.maxintnullableC7798? Net 0.5-8 keV counts in ObsID 7798ctphot.count;em.X-rayintnullablee_C7798? Lower uncertainty limit on C7798ctstat.errorintnullableE_C7798? Upper uncertainty limit on C7798ctstat.error;stat.maxintnullablef_C7798Flag on C7798 (1)meta.codecharC7799? Net 0.5-8 keV counts in ObsID 7799ctphot.count;em.X-rayintnullablee_C7799? Lower uncertainty limit on C7799ctstat.errorintnullableE_C7799? Upper uncertainty limit on C7799ctstat.error;stat.maxintnullablef_C7799Flag on C7799 (1)meta.codecharC7800? Net 0.5-8 keV counts in ObsID 7800ctphot.count;em.X-rayintnullablee_C7800? Lower uncertainty limit on C7800ctstat.errorintnullableE_C7800? Upper uncertainty limit on C7800ctstat.error;stat.maxintnullablef_C7800Flag on C7800 (1)meta.codecharC8449Net 0.5-8 keV counts in ObsID 8449ctphot.count;em.X-rayinte_C8449? Lower uncertainty limit on C8449ctstat.errorintnullableE_C8449? Upper uncertainty limit on C8449ctstat.error;stat.maxintnullablef_C8449Flag on C8449 (1)meta.codecharC8490Net 0.5-8 keV counts in ObsID 8490ctphot.count;em.X-rayinte_C8490Lower uncertainty limit on C8490ctstat.errorintE_C8490Upper uncertainty limit on C8490ctstat.error;stat.maxintG-LmIntra-observational variability (G-L_max_)src.var.indexintTypeSource classification (2)meta.code.classNoteAdditional notes (GC coincident numbers from Woodley+, 2008, J/ApJ/682/199)meta.notecharJ/ApJ/766/88/table2Cen A Sources: Spectral fitting and State Identificationchi2POThe {chi}^2^ of the PO fitstat.fit.chi2floatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDSource identifiermeta.id;meta.maincharObsIDObservation identifier(s)meta.id;obs.param;obscharNHPOHydrogen column density of absorbed power law model1e+22cm**-2phys.columnDensityfloate_NHPOLower limit uncertainty in NHPO (1)1e+22cm**-2stat.errorfloatE_NHPOUpper limit uncertainty in NHPO (1)1e+22cm**-2stat.error;stat.maxfloatSpIPOSpectral index of absorbed power law model {Gamma}^PO^spect.indexfloate_SpIPOLower limit uncertainty in SpIPO (1)stat.errorfloatE_SpIPOUpper limit uncertainty in SpIPO (1)stat.error;stat.maxfloatLxPO1Minimal absorbed power law model 0.5-10keV luminosity (in 10^37^erg/s)1e+30Wphys.luminosity;em.X-ray.medium;meta.modelledfloate_LxPO1Lower limit uncertainty in LxPO1 (1)1e+30Wstat.errorfloatE_LxPO1Upper limit uncertainty in LxPO1 (1)1e+30Wstat.error;stat.maxfloatLxPO2? Maximal absorbed power law model 0.5-10 keV luminosity (in 10^37^erg/s)1e+30Wphys.luminosity;em.X-rayfloatnullablee_LxPO2? Lower limit uncertainty in LxPO2 (1)1e+30Wstat.errorfloatnullableE_LxPO2? Upper limit uncertainty in LxPO2 (1)1e+30Wstat.error;stat.maxfloatnullableDoFPODegrees of freedom of power law fitstat.fit.dofintNHDBB? Hydrogen column density of disk blackbody model (2)1e+22cm**-2phys.columnDensityfloatnullablee_NHDBB? Lower limit uncertainty in NHDBB (1)1e+22cm**-2stat.errorfloatnullableE_NHDBB? Upper limit uncertainty in NHDBB (1)1e+22cm**-2stat.error;stat.maxfloatnullablekTDBB? Temperature of disk blackbody model (2)keVphys.temperaturefloatnullablee_kTDBB? Lower limit uncertainty in kTDBB (1)keVstat.errorfloatnullableE_kTDBB? Upper limit uncertainty in kTDBB (1)keVstat.error;stat.maxfloatnullableLxDBB1? Minimal disk blackbody model 0.5-10 keV luminosity (in 10^37^erg/s) (2)1e+30Wphys.luminosity;em.X-rayfloatnullablee_LxDBB1? Lower limit uncertainty in LxDBB1 (1)1e+30Wstat.errorfloatnullableE_LxDBB1? Upper limit uncertainty in LxDBB1 (1)1e+30Wstat.error;stat.maxfloatnullableLxDBB2? Maximal disk blackbody model 0.5-10 keV luminosity (in 10^37^erg/s) (2)1e+30Wphys.luminosity;em.X-rayfloatnullablee_LxDBB2? Lower limit uncertainty in LxDBB2 (1)1e+30Wstat.errorfloatnullableE_LxDBB2? Upper limit uncertainty in LxDBB2 (1)1e+30Wstat.error;stat.maxfloatnullablechi2DBB? The {chi}^2^ of the disk blackbody fit (2)stat.fit.chi2floatnullableDoFDBB? Degrees of freedom of disk blackbody fit (2)stat.fit.dofintnullableStateSpectral state(s) (3)meta.notecharJ/ApJ/766/88/table3Spectral fits using inferred dominant model (0.5-8.0keV)DoFDegrees of Freedomstat.fit.dofintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDSource identifier (1)meta.id;meta.maincharNH[0.08/1.1] Hydrogen column density1e+22cm**-2phys.columnDensityfloate_NHLower limit uncertainty in NH1e+22cm**-2stat.errorfloatE_NHUpper limit uncertainty in NH1e+22cm**-2stat.error;stat.maxfloatkT? Model DBB fit parameter (1)keVphys.temperaturefloatnullablee_kT? Lower limit uncertainty in kTkeVstat.error;phys.energyfloatnullableE_kT? Upper limit uncertainty in kTkeVstat.error;stat.maxfloatnullableGam? Model power_law parameter (1)stat.param;meta.modelledfloatnullablee_Gam? Lower limit uncertainty in Gamstat.errorfloatnullableE_Gam? Upper limit uncertainty in Gamstat.error;stat.maxfloatnullableLx1[2.4/36.3] Minimal 0.5-10 keV luminosity1e+30Wphys.luminosity;em.X-rayfloate_Lx1Lower limit uncertainty in Lx11e+30Wstat.errorfloatE_Lx1Upper limit uncertainty in Lx11e+30Wstat.error;stat.maxfloatLx2? Maximal 0.5-10 keV luminosity1e+30Wphys.luminosity;em.X-rayfloatnullablee_Lx2? Lower limit uncertainty in Lx21e+30Wstat.errorfloatnullableE_Lx2? Upper limit uncertainty in Lx21e+30Wstat.error;stat.maxfloatnullablechi2Model {chi}^2^ of fitstat.param;meta.modelledfloatNote[D GC] Source coincidence (2)meta.notechar