CHANTYPGPR ivo://nasa.heasarc/chantypgpr NASA/GSFC HEASARC Ebisawa et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source Using the Chandra Advanced CCD Imaging Spectrometer Imaging array (ACIS-I), the authors carried out a deep hard X-ray observation of the Galactic plane region at a location (l, b) ~ (28.5 degrees, 0.0 degrees), where no discrete X-ray source had been reported previously. They detected 274 new point X-ray sources (4-sigma or greater confidence in any of the 3 energy bands 0.5 - 3.0 keV, 3.0 - 8.0 keV or 0.5 - 8.0 keV), as well as strong Galactic diffuse emission within two partially overlapping ACIS-I fields (~ 250 square arcminutes in total). The point-source sensitivity was ~ 3 x 10<sup>-15</sup> ergs/s/cm<sup>2</sup> in the 2 - 10 keV band and ~ 2 x 10<sup>-16</sup> erg/s/cm<sup>2</sup> in the 0.5 - 2 keV band The sum of all the detected point-source fluxes accounts for only ~ 10% of the total X-ray flux in the field of view. Only 26 point sources were detected in both the soft and hard bands, indicating that there are two distinct classes of X-ray source distinguished by their spectral hardness ratios. The surface number density of the hard sources is only slightly higher than that measured in high Galactic latitude regions, indicating that the majority of the hard sources are background AGNs. Following up the Chandra observation, the authors performed a near-infrared (NIR) survey with SofI at ESO/NTT. Almost all the soft X-ray sources have been identified in the NIR, and their spectral types are consistent with main-sequence stars, suggesting that most of them are nearby X-ray-active stars. On the other hand, only 22% of the hard sources had near-IR counterparts, which are presumably Galactic. From X-ray and near-IR spectral study, they are most likely to be quiescent cataclysmic variables. This Browse table was created by the HEASARC in December 2006 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/635/214/">CDS Catalog J/ApJ/635/214/</a>, the file table1.dat. This is a service provided by NASA HEASARC . 2005ApJ...635..214E https://heasarc.gsfc.nasa.gov/W3Browse/all/chantypgpr.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=chantypgpr& GET text/xml 180 99999 true 281.06770833 -4.21583333 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=chantypgpr GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_chantypgpr&Action=More+Options&Action=Parameter+Search&ConeAdd=1 CHANDRA 0.0166666666666667 X-ray public chantypgpr Chandra Typical Galactic Plane Region Point Source Catalog name Source Designation meta.id;meta.main char nullable ra Right Ascension degree pos.eq.ra;meta.main double nullable dec Declination degree pos.eq.dec;meta.main double nullable error_radius Positional Error arcsec stat.error;pos float nullable fb_count_rate Total Band (0.5-8.0 keV) Normalized Count Rate ct/s double nullable fb_count_rate_snr Total Band (0.5-8.0 keV) Sigma Significance double nullable "__x_ra_dec" System unit vector column double nullable "__y_ra_dec" System unit vector column double nullable "__z_ra_dec" System unit vector column double nullable "__row" System index column char nullable sb_flux Soft Band (0.5-2.0 keV) Flux (erg/s/cm^2) erg/s/cm^2 double nullable hb_flux Hard Band (2.0-10.0 keV) Flux (erg/s/cm^2) erg/s/cm^2 double nullable jmag 2MASS J Band Magnitude mag double nullable lii Galactic Longitude degree pos.galactic.lon double nullable hb_count_rate_snr Hard Band (3.0-8.0 keV) Sigma Significance double nullable off_set Near-IR Counterpart Separation (arcsec) arcsec instr.offset double nullable source_number Sequential Identification Number for Each Source in Catalog meta.id short nullable sb_count_rate Soft Band (0.5-3.0 keV) Normalized Count Rate ct/s double nullable hmag 2MASS H Band Magnitude mag double nullable ao Announcement of Opportunity Cycle char nullable near_ir_name Near-IR Counterpart Identification, Either SOFI or 2MASS char nullable hardness_ratio Hardness Ratio, (H-S)/(H+S) phot.flux;arith.ratio;em.X-ray.medium;em.X-ray.soft double nullable sb_count_rate_snr Soft Band (0.5-3.0 keV) Sigma Significance double nullable bii Galactic Latitude degree pos.galactic.lat double nullable ks_mag 2MASS Ks Band Magnitude mag double nullable source_flag Flag: T=Source Shows Significant Time Variation, E=Extended Source char nullable hb_count_rate Hard Band (3.0-8.0 keV) Normalized Count Rate ct/s double nullable hardness_ratio_error Error in Hardness Ratio stat.error;phot.flux;arith.ratio;em.X-ray.medium;em.X-ray.soft double nullable