J/MNRAS/388/849ivo://CDS.VizieR/J/MNRAS/388/849doi:10.26093/cds/vizier.73880849CDSBarnard R.Greening L.S.Kolb U.2024-07-07T20:16:41Z2009-04-11T14:41:14ZCDS support team

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

cds-question@unistra.frgalaxiesx-ray-sourcesNGC 253 is a local, starbursting spiral galaxy with strong X-ray emission from hot gas, as well as many point sources. We have conducted a spectral survey of the X-ray population of NGC 253 using a deep XMM-Newton observation. NGC 253 only accounts for ~20 per cent of the XMM-Newton EPIC field of view, allowing us to identify ~100 X-ray sources that are unlikely to be associated with NGC 253. Hence, we were able to make a direct estimate of contamination from, for example, foreground stars and background galaxies. X-ray luminosity functions (XLFs) of galaxy populations are often used to characterize their properties. There are several methods for estimating the luminosities of X-ray sources with few photons. We have obtained spectral fits for the brightest 140 sources in the 2003 XMM-Newton observation of NGC 253, and compare the best-fitting luminosities of those 69 non-nuclear sources associated with NGC 253 with luminosities derived using other methods. We find the luminosities obtained from these various methods to vary systematically by a factor of up to 3 for the same data; this is largely due to differences in absorption. We therefore conclude that assuming Galactic absorption is probably unwise; rather, one should measure the absorption for the population.2008MNRAS.388..849Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/388/849CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/649/730 : ULX population in nearby galaxies from XMM (Winter+, 2006)B/xmm : XMM-Newton Observation Log (XMM-Newton SOC, 2007)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/388/849https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/388/849http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/388/849https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/388/849https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/388/849http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/388/849GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/388/849/tablea (Positions of X-ray sources in the XMM-Newton observations of NGC 253, along with some observed and spectral properties)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/388/849/tablea?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/388/849/tablea?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/388/849/tablea?GETtext/xml+votable180.050000true11.613-25.3560.0055555555555555566/16653 16655 16664 16666https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/388/849?format=asciiX-raydefaultJ/MNRAS/388/849/tableaPositions of X-ray sources in the XMM-Newton observations of NGC 253, along with some observed and spectral propertiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[BGK2008]Source sequential number (G1)meta.recordintRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.maininD25[yn] indicates whether the source is within the D25 isophotal region of NGC 253meta.codecharRsSource extraction radiusarcsecphys.angSizeintAb/AsBackground-to-source area ratiophys.angSizefloatEEFEncircled energy fraction (1)phys.size;arith.ratiofloatCtPNpn source countsctphot.count;em.X-rayintCtMOSMOS source countsctphot.count;em.X-rayintModBest fitting model (1)stat.param;meta.modelledcharNH? Absorption1e+22cm**-2phys.absorptionfloatnullablee_NH? rms uncertainty on NH at 90% confidence level1e+22cm**-2stat.errorfloatnullablef_NH[f] f for fixed absorptionmeta.codecharParam? Parameter (spectral index or temperature) (2)stat.fit.paramfloatnullablee_Param? rms uncertainty on Param at 90% confidence levelstat.errorfloatnullableParam2? Second parameter value (spectral index or temperature) (2)stat.fit.paramfloatnullablee_Param2? rms uncertainty on Param2 at 90% confidence levelstat.errorfloatnullablechi2? chi^2^ valuestat.fit.chi2floatnullableDOF? Degree Of Freedom (3)stat.fit.dofintnullablegf? Good fit probabilitystat.fit.goodnessfloatnullableLBF? Best-fitting luminosity1e+29Wphys.luminosity;em.X-raydoublenullablee_LBF? rms uncertainty on LBF at 90% confidence level1e+29Wstat.errordoublenullableLSM? Standard model (Method I) luminosity1e+29Wphys.luminosity;em.X-rayfloatnullable