J/ApJ/892/16ivo://CDS.VizieR/J/ApJ/892/16doi:10.26093/cds/vizier.18920016CDSCheng Z.Mu H.Li Z.Xu X.Wang W.Li X.2022-09-06T12:17:40Z2021-09-10T14:45:05ZCDS support team

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

cds-question@unistra.frglobular-star-clustersx-ray-sourcesUsing archival Chandra observations with a total effective exposure of 323ks, we derive an updated catalog of point sources in the bulge globular cluster M28. The catalog contains 502 X-ray sources within an area of ~475arcmin^2^, and more than 90% of these sources are first detected in this cluster. We find significant dips in the radial distribution profiles of X-ray sources in M28, and the projected distance and width of the distribution dip for bright (L_X_>~4.5x10^30^erg/s) X-ray sources are larger than for faint (L_X_<~4.5x10^30^erg/s) sources. Fitting with the "generalized King model" gives a slightly larger average mass for the bright sources (1.30+/-0.15M_{sun}_) than for the faint ones (1.09+/-0.14M_{sun}_), which supports a universal delay in mass segregation between heavy objects in globular clusters. We show that the dynamical age of M28 is comparable to that of Terzan 5 and much smaller than that of 47 Tuc, but M28 is evolving faster (i.e., with a shorter two-body relaxation timescale) than 47 Tuc. These features may suggest an acceleration effect of cluster dynamical evolution by tidal shock in M28. Besides, we find an abnormal deficiency of X-ray sources in the central region (R<~1.5') of M28 compared with its outskirts, which indicates that M28 may have suffered an early phase of primordial binary disruption within its central region, and the mass segregation effect will erase such a phenomenon as clusters evolve to an older dynamical age.2020ApJ...892...16Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/892/16CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/chandra : The Chandra Archive Log (CXC, 1999-2014)VII/195 : Globular Clusters in the Milky Way (Harris, 1996)VII/202 : Globular Clusters in the Milky Way (Harris, 1997)J/AJ/121/916 : HST obs. of NGC 2298, 5897, 6535, and 6626 (Testa+, 2001)J/ApJS/166/249 : Stellar dynamics & PMs in 47Tuc (McLaughlin+, 2006)J/MNRAS/482/5138 : Galactic GC mean PMs & velocities (Baumgardt+, 2019)J/ApJ/876/59 : Chandra X-ray sources in 47 Tuc (Cheng+, 2019)J/ApJ/883/90 : X-ray mass segregation effect in GCs. II. (Cheng+, 2019)J/A+A/632/A3 : MUSE binaries in NGC 3201 (Giesers+, 2019)J/A+A/651/A47 : Variable stars in VVV globulars. II. (Alonso-Garcia+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/892/16https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/892/16http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/892/16https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/892/16https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/892/16http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/892/16GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/892/16/table2 (Main Chandra source catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/892/16/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/892/16/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/892/16/table2?GETtext/xml+votable180.050000true275.886925-24.816633890.0055555555555555566/28799 28970https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/892/16?format=asciiX-raydefaultJ/ApJ/892/16/table2Main Chandra source catalogrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1/502] X-ray catalog sequence number, RA sortedmeta.idintNameIAU designation (HHMMSS.ss+DDMMSS.s; J2000)meta.id;meta.maincharRAJ2000[275.88/276.42] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-25.1/-24.7] Declination (J2000)degpos.eq.dec;meta.mainPosErr[0/1.6] 1{sigma} positional uncertaintyarcsecstat.error;posfloatR[1.8/924] Projected distance from cluster center (1)arcsecpos.angDistancefloatPB[0/0.051] logarithmic Poisson probability of a detection not being a sourcestat.fit.goodnessdoubleCnet-t[4.6/11352] Full (0.5-8keV) band aperture-corrected source countsctphot.count;em.X-rayfloatb_Cnet-t[0.2/11245] 1{sigma} lower bound of Cnet-tctphot.count;em.X-ray;stat.minfloatB_Cnet-t[8.3/114560] 1{sigma} upper bound of Cnet-tctphot.count;em.X-ray;stat.maxfloatCnet-s[-5.7/10737] Soft (0.5-2 keV) band aperture-corrected source countsctphot.count;em.X-rayfloatb_Cnet-s[0/10633]? 1{sigma} lower bound of Cnet-sctphot.count;em.X-ray;stat.minfloatnullableB_Cnet-s[2/10842] 1{sigma} upper bound of Cnet-sctphot.count;em.X-ray;stat.maxfloatCnet-h[-5.2/3713] Hard (2-8keV) band aperture-corrected source countsctphot.count;em.X-rayfloatb_Cnet-h[0/3652]? 1{sigma} lower bound of Cnet-hctphot.count;em.X-ray;stat.minfloatnullableB_Cnet-h[1/3774] 1{sigma} upper bound of Cnet-hctphot.count;em.X-ray;stat.maxfloatFlux-t[6e-8/0.00014] Full (0.5-8keV) band photon fluxph.cm**-2.s**-1phot.flux;em.X-raydoubleFlux-s[-1.1e-7/7.8e-5] Soft (0.5-8keV) band photon fluxph.cm**-2.s**-1phot.flux;em.X-raydoubleFlux-h[-7.6e-8/5.1e-5] Hard (2-8keV) band photon fluxph.cm**-2.s**-1phot.flux;em.X-raydoubleLum-tc[8.8e+29/1.5e+33] Absorption-corrected intrinsic 0.5-8.0keV luminosity; erg/s (2)1e-07Wphys.luminosity;em.X-raydoubleLum-sc[2.6e+29/1.2e+33] Absorption-corrected intrinsic 0.5-2.0keV luminosity; erg/s (2)1e-07Wphys.luminosity;em.X-raydoubleLum-hc[6.1e+29/1.2e+33] Absorption-corrected intrinsic 2.0-8.0keV luminosity; erg/s (2)1e-07Wphys.luminosity;em.X-raydoublelogNH[21.3/22.7] Log of absorption column densitylog(cm**-2)phys.columnDensityfloatb_logNH[21.3/22.6]? 1{sigma} lower bound of logNH (3)log(cm**-2)phys.columnDensity;stat.minfloatnullableB_logNH[21.4/22.8]? 1{sigma} upper bound of logNH (3)log(cm**-2)phys.columnDensity;stat.maxfloatnullableGamma[0.09/3.3] Photon index of power-law modelmeta.code;spect.index;meta.modelledfloatb_Gamma[0.2/3.2]? 1{sigma} lower bound of Gamma (3)meta.notefloatnullableB_Gamma[0.5/3]? 1{sigma} upper bound of Gamma (3)meta.notefloatnullabledof[1179/1183] Cstatistic degrees of freedomstat.fit.dofintCStat[249/1909] Cstatistic values using 1192 PHA binsstat.fit.paramint