M101CXO ivo://nasa.heasarc/m101cxo NASA/GSFC HEASARC Pence et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source A deep (98.2ks) Chandra Cycle 1 observation has revealed a wealth of discrete X-ray sources as well as diffuse emission in the nearby face-on spiral galaxy M 101. From this rich data set, the authors have created a catalog of the 110 sources from the S3 chip which were detected with a significance of greater than 3-sigma. This detection threshold corresponds to a flux of ~ 10<sup>-16</sup> ergs/cm<sup>2</sup>/s and a luminosity of ~ 10<sup>36</sup> ergs/s for a distance to M 101 of 7.2 Mpc. The sources display a distinct correlation with the spiral arms of M101 and include a variety of X-ray binaries, supersoft sources, supernova remnants, and other objects of which only ~27 are likely to be background sources. The 29 brightest sources have enough flux (greater than 100 counts) to perform at least crude spectral modeling using the HEASARC XSPEC model fitting program. Most of the sources could be satisfactorily fitted with a simple absorbed power-law spectrum model; however, eight of the softest sources were better fitted by an absorbed blackbody model. This table was created by the HEASARC in July 2007 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/561/189">CDS Catalog J/ApJ/561/189</a> files table1.dat and table4.dat. This is a service provided by NASA HEASARC . 2001ApJ...561..189P https://heasarc.gsfc.nasa.gov/W3Browse/all/m101cxo.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=m101cxo& GET text/xml 180 99999 true 210.884375 54.25980556 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=m101cxo GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_m101cxo&Action=More+Options&Action=Parameter+Search&ConeAdd=1 CHANDRA 0.0166666666666667 X-ray public m101cxo M 101 Chandra X-Ray 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 sb2_counts Second Soft X-Ray Energy Band Net Counts ct phot.count;em.X-ray.soft short nullable mb2_counts Second Medium X-Ray Energy Band Net Counts ct phot.count;em.X-ray.soft short nullable hb2_counts Second Hard X-Ray Energy Band Net Counts ct phot.count;em.X-ray.medium short nullable sb2_flux S2 X-Ray Flux erg/s/cm^2 phot.flux;em.X-ray.soft double nullable mb2_flux M2 X-Ray Flux erg/s/cm^2 phot.flux;em.X-ray.soft double nullable hb2_flux H2 X-Ray flux erg/s/cm^2 phot.flux;em.X-ray.medium double nullable source_number Sequential Identification Number for Each X-Ray Source in Catalog meta.id short nullable nh Hydrogen Column Density cm^-2 phys.columnDensity;stat.fit.param double nullable bb_kt Absorbed Blackbody Model Parameter keV phys.temperature;stat.fit.param double nullable model_sb2_flux X-Ray Flux over the Energy Range of the S2 Energy Band erg/s/cm^2 phot.flux;em.X-ray.soft double nullable hb1_counts First Hard X-Ray Energy Band Net Counts ct phot.count;em.X-ray.medium short nullable lii Galactic Longitude degree pos.galactic.lon double nullable hb2_log_lx X-Ray Luminosity in H2 Energy Band erg/s phys.luminosity;em.X-ray.medium double nullable sb1_counts First Soft X-Ray Energy Band Net Counts ct phot.count;em.X-ray.soft short nullable mb1_counts First Medium X-Ray Energy Band Net Counts ct phot.count;em.X-ray.soft short nullable model_hb2_flux X-Ray Flux over the Energy Range of the H2 Energy Band erg/s/cm^2 phot.flux;em.X-ray.medium double nullable sb2_log_lx X-Ray Luminosity in S2 Energy Band erg/s phys.luminosity;em.X-ray.soft double nullable reduced_chi_squared Reduced Chi^2 Value stat.fit.chi2 double nullable source_region Area of Source Region in Units of Chandra CCD Pixels pixel phys.angArea short nullable spectral_index Simple Absorbed Power-Law Spectrum Model Parameter spect.index;em.X-ray double nullable bii Galactic Latitude degree pos.galactic.lat double nullable mb2_log_lx X-Ray Luminosity in M2 Energy Band erg/s phys.luminosity;em.X-ray.soft double nullable model_mb2_flux X-Ray Flux over the Energy Range of the M2 Energy band erg/s/cm^2 phot.flux;em.X-ray.soft 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