J/ApJ/825/132ivo://CDS.VizieR/J/ApJ/825/132doi:10.26093/cds/vizier.18250132CDSHong J.Mori K.Hailey C.J.Nynka M.Zhang S.Gotthelf E.,Fornasini F.M.Krivonos R.Bauer F.Perez K.Tomsick J.A.Bodaghee A.,Chiu J.-L.Clavel M.Stern D.Grindlay J.E.Alexander D.M.Aramaki T.,Baganoff F.K.Barret D.Barriere N.Boggs S.E.Canipe A.M.,Christensen F.E.Craig W.W.Desai M.A.Forster K.Giommi P.,Grefenstette B.W.Harrison F.A.Hong D.Hornstrup A.Kitaguchi T.,Koglin J.E.Madsen K.K.Mao P.H.Miyasaka H.Perri M.Pivovaroff M.J.,Puccetti S.Rana V.Westergaard N.J.Zhang W.W.Zoglauer A.2021-01-25T12:12:55Z2018-03-12T12:12:46ZCDS support team

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

cds-question@unistra.frmilky-way-galaxygalactic-centerx-ray-sourcesx-ray-binary-starsphotometryWe present the first survey results of hard X-ray point sources in the Galactic Center (GC) region by NuSTAR. We have discovered 70 hard (3-79 keV) X-ray point sources in a 0.6 deg^2^ region around Sgr A* with a total exposure of 1.7 Ms, and 7 sources in the Sgr B2 field with 300 ks. We identify clear Chandra counterparts for 58 NuSTAR sources and assign candidate counterparts for the remaining 19. The NuSTAR survey reaches X-ray luminosities of ~4x and ~8x10^32^ erg/s at the GC (8 kpc) in the 3-10 and 10-40 keV bands, respectively. The source list includes three persistent luminous X-ray binaries (XBs) and the likely run-away pulsar called the Cannonball. New source-detection significance maps reveal a cluster of hard (>10 keV) X-ray sources near the Sgr A diffuse complex with no clear soft X-ray counterparts. The severe extinction observed in the Chandra spectra indicates that all the NuSTAR sources are in the central bulge or are of extragalactic origin. Spectral analysis of relatively bright NuSTAR sources suggests that magnetic cataclysmic variables constitute a large fraction (>40%-60%). Both spectral analysis and logN-logS distributions of the NuSTAR sources indicate that the X-ray spectra of the NuSTAR sources should have kT>20 keV on average for a single temperature thermal plasma model or an average photon index of {Gamma}=1.5-2 for a power-law model. These findings suggest that the GC X-ray source population may contain a larger fraction of XBs with high plasma temperatures than the field population.2016ApJ...825..132Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/825/132CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/chandra : The Chandra Archive Log (CXC, 1999-2014)J/A+A/368/835 : Soft X-ray sources in the Galactic Center regionJ/ApJ/589/225 : Chandra X-ray sources toward Galactic Center (Muno+, 2003)J/ApJ/613/1179 : X-ray sources in Galactic Center (Muno+, 2004)J/PAZh/30/430 : INTEGRAL X-ray source in Galactic center (Revnivtsev+, 2004)J/ApJS/165/173 : Chandra sources in Galaxy central 150pc (Muno+, 2006)J/MNRAS/371/38 : X-ray observations of the Galaxy center (Wang+, 2006)J/ApJ/706/223 : X-ray point sources near the Galactic Center (Hong+, 2009)J/ApJS/181/110 : Galactic center X-ray sources (Muno+, 2009)J/ApJ/836/99 : NuSTAR serendipitous survey: the 40-month cataloghttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/825/132https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/825/132http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/825/132https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/825/132https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/825/132http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/825/132GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/825/132/table35 (NuSTAR Point Sources (table 3) and Aperture Photometry Results (table 5) in the Sgr B2 Field)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/825/132/table35?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/825/132/table35?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/825/132/table35?GETtext/xml+votable180.050000true266.68683-28.265110.005555555555555556Cone search capability for table J/ApJ/825/132/table24 (NuSTAR Galactic Point (NGP) Source List (table 2) and Aperture Photometry Results (table 4))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/825/132/table24?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/825/132/table24?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/825/132/table24?GETtext/xml+votable180.050000true266.58731-28.72770.0055555555555555566/28827 28830 28831https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/825/132?format=asciiX-raydefaultJ/ApJ/825/132/table35NuSTAR Point Sources (table 3) and Aperture Photometry Results (table 5) in the Sgr B2 FieldFlagThe NuSTAR flags (9)meta.code.errorchare_QRUncertainty in QR (1)stat.errorfloatChandraChandra counterpart name (HHMMSS.s+DDMMSS)meta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGroup[1/2] Group number (G1)meta.idintID[1/77] NuSTAR Galactic Center Point (NGP) source identifiermeta.id;meta.mainintRAJ2000Right Ascension in decimal degrees (J2000) (1)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000) (1)degpos.eq.dec;meta.mainChandraM[321/8943] Chandra counterpart identifier by Muno et al. 2009 (J/ApJS/181/110)meta.id.crossintFX(2-8)Chandra 2-8 keV flux of the counterpart (in cgs)1e-06ph.cm**-2.s**-1phot.flux;em.X-rayfloatOffsetAngular offset between the NuSTAR and Chandra positionsarcsecpos.angDistance;arith.difffloatExpCombined exposure of the two NuSTAR focal plane modules (FPMs) at the Chandra source positionksinstr.tel.focalLength;obs.exposureintDet[S H SH] An indicator of the soft (S<10 keV) and/or hard (H>10 keV) band detectionmeta.codecharTrialTrial map value at the Chandra position (2)stat.fit.paramfloatb_Band[3/10] Energy band of the trial map with the local peak value, lower valuekeVem.energyintB_Band[10/79] Energy band of the trial map with the local peak value, upper valuekeVem.energyintSize[15/30] Source cell size of the trial map with the local peak value%instr.fov;instr.pixelintNDetec[0/15] Number of trial maps above their respective thresholds at the Chandra positionmeta.numberintComA known name, nearby Chandra source, and/or notable diffuse feature nearbymeta.notecharCountNet counts in the 3-40 keV bandctphot.count;em.X-rayinte_CountUncertainty in Count (1)ctstat.error;phot.countintBEHRThe mode of the posterior distribution of Bayesian Enhanced X-ray Hardness Ratio (BEHR) (2)instr.setupfloate_BEHRUncertainty in BEHR (1)stat.errorfloatn_e_BEHR[*] Note on e_BEHR (3)meta.notecharE50Median energy of the NuSTAR spectrum in 3-40 keVkeVem.energyfloate_E50Uncertainty in E50 (1)keVstat.errorfloatn_e_E50[*] Note on e_E50 (3)meta.notecharQRA relative ratio of 25% and 75% quartiles: 3(E_25_-3 keV)/(E_75_-3 keV) (4)stat.paramfloatn_e_QR[*] Note on e_QR (3)meta.notecharNHAn estimate of N_H_ along the line of sight (Nishiyama et al. 2008ApJ...680.1174N)1e+22cm**-2phys.columnDensityfloatIndexAn estimate of photon index using the median energy for an absorbed power-law model with N_H_=6x10^22^/cm^2^ (Section 4.3)spect.indexfloate_IndexUncertainty in Index (1)stat.error;spect.indexfloatn_e_Index[+] Note on e_Index (5)meta.notecharFX(3-10)The observed NuSTAR 3-10 keV flux1e-06ph.s**-1.cm**-2phot.flux;em.X-rayfloate_FX(3-10)Uncertainty in FX(3-10) (1)1e-06ph.s**-1.cm**-2stat.errorfloatn_e_FX(3-10)[*] Note on e_FX(3-10) (3)meta.notecharFX(10-40)The observed NuSTAR 10-40 keV flux1e-06ph.s**-1.cm**-2phot.flux;em.X-rayfloate_FX(10-40)Uncertainty in FX(10-40) (1)1e-06ph.s**-1.cm**-2stat.errorfloatn_e_FX(10-40)[*] Note on e_FX(10-40) (3)meta.notecharLX(3-10)The observed NuSTAR 3-10 keV luminosity at 8 kpc (in 10^32^erg/s)1e+25Wphys.luminosity;em.X-rayfloate_LX(3-10)Uncertainty in LX(3-10) (1)1e+25Wstat.errorfloatn_e_LX(3-10)[*] Note on e_LX(3-10) (3)meta.notecharLX(10-40)The observed NuSTAR 10-40 keV luminosity at 8 kpc (in 10^32^erg/s)1e+25Wphys.luminosity;em.X-rayfloate_LX(10-40)Uncertainty in LX(10-40) (1)1e+25Wstat.errorfloatn_e_LX(10-40)[*] Note on e_LX(10-40) (3)meta.notecharSize1Source and background aperture radii flag, for the first aperture set (7)meta.codecharn_Size1[a] Note on Size1 (8)meta.notecharSize2Source and background aperture radii flag, for the second aperture set (7)meta.codecharn_Size2[a] Note on Size2 (8)meta.notecharSimbadSimbad column added by the CDSmeta.ref.urlcharJ/ApJ/825/132/table24NuSTAR Galactic Point (NGP) Source List (table 2) and Aperture Photometry Results (table 4)Det[S H SH] An indicator of the soft (S<10 keV) and/or hard (H>10 keV) band detectionmeta.codechare_BEHRUncertainty in BEHR (1)stat.errorfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGroup[1/2] Group number (G1)meta.idintID[1/77] NuSTAR Galactic Center Point (NGP) source identifiermeta.id;meta.mainintRAJ2000Right Ascension in decimal degrees (J2000) (1)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000) (1)degpos.eq.dec;meta.mainChandraM[321/8943] Chandra counterpart identifier by Muno et al. 2009 (J/ApJS/181/110)meta.id.crossintChandraChandra counterpart name (HHMMSS.s+DDMMSS)meta.idcharFX(2-8)Chandra 2-8 keV flux of the counterpart (in cgs)1e-06ph.cm**-2.s**-1phot.flux;em.X-rayfloatOffsetAngular offset between the NuSTAR and Chandra positionsarcsecpos.angDistance;arith.difffloatExpCombined exposure of the two NuSTAR focal plane modules (FPMs) at the Chandra source positionksinstr.tel.focalLength;obs.exposureintTrialTrial map value at the Chandra position (2)stat.fit.paramfloatb_Band[3/10] Energy band of the trial map with the local peak value, lower valuekeVem.energyintB_Band[10/79] Energy band of the trial map with the local peak value, upper valuekeVem.energyintSize[15/30] Source cell size of the trial map with the local peak value%instr.fov;instr.pixelintNDetec[0/15] Number of trial maps above their respective thresholds at the Chandra positionmeta.numberintComA known name, nearby Chandra source, and/or notable diffuse feature nearbymeta.notecharCountNet counts in the 3-40 keV bandctphot.count;em.X-rayinte_CountUncertainty in Count (1)ctstat.error;phot.countintBEHRThe mode of the posterior distribution of Bayesian Enhanced X-ray Hardness Ratio (BEHR) (2)instr.setupfloatn_e_BEHR[*] Note on e_BEHR (3)meta.notecharE50Median energy of the NuSTAR spectrum in 3-40 keVkeVem.energyfloate_E50Uncertainty in E50 (1)keVstat.errorfloatn_e_E50[*] Note on e_E50 (3)meta.notecharQRA relative ratio of 25% and 75% quartiles: 3(E_25_-3 keV)/(E_75_-3 keV) (4)stat.paramfloate_QRUncertainty in QR (1)stat.errorfloatn_e_QR[*] Note on e_QR (3)meta.notecharNHAn estimate of N_H_ along the line of sight (Nishiyama et al. 2008ApJ...680.1174N)1e+22cm**-2phys.columnDensityfloatIndexAn estimate of photon index using the median energy for an absorbed power-law model with N_H_=6x10^22^/cm^2^ (Section 4.3)spect.indexfloate_IndexUncertainty in Index (1)stat.error;spect.indexfloatn_e_Index[+] Note on e_Index (5)meta.notecharFX(3-10)The observed NuSTAR 3-10 keV flux1e-06ph.s**-1.cm**-2phot.flux;em.X-rayfloate_FX(3-10)Uncertainty in FX(3-10) (1)1e-06ph.s**-1.cm**-2stat.errorfloatn_e_FX(3-10)[*] Note on e_FX(3-10) (3)meta.notecharFX(10-40)The observed NuSTAR 10-40 keV flux1e-06ph.s**-1.cm**-2phot.flux;em.X-rayfloate_FX(10-40)Uncertainty in FX(10-40) (1)1e-06ph.s**-1.cm**-2stat.errorfloatn_e_FX(10-40)[*] Note on e_FX(10-40) (3)meta.notecharLX(3-10)The observed NuSTAR 3-10 keV luminosity at 8 kpc (in 10^32^erg/s)1e+25Wphys.luminosity;em.X-rayfloate_LX(3-10)Uncertainty in LX(3-10) (1)1e+25Wstat.errorfloatn_e_LX(3-10)[*] Note on e_LX(3-10) (3)meta.notecharLX(10-40)The observed NuSTAR 10-40 keV luminosity at 8 kpc (in 10^32^erg/s)1e+25Wphys.luminosity;em.X-rayfloate_LX(10-40)Uncertainty in LX(10-40) (1)1e+25Wstat.errorfloatn_e_LX(10-40)[*] Note on e_LX(10-40) (3)meta.notecharSize1Source and background aperture radii flag, for the first aperture set (7)meta.codecharn_Size1[a] Note on Size1 (8)meta.notecharSize2Source and background aperture radii flag, for the second aperture set (7)meta.codecharn_Size2[a] Note on Size2 (8)meta.notecharFlagThe NuSTAR flags (9)meta.code.errorcharSimbadSimbad column added by the CDSmeta.ref.urlchar