Ultraluminous X-Ray Sources in Nearby Galaxies Catalog

Ultraluminous X-Ray Sources in Nearby Galaxies Catalog ULXNGCAT ivo://nasa.heasarc/ulxngcat NASA/GSFC HEASARC Swartz et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source One hundred and seven ultraluminous X-ray sources (ULXs) with 0.3-10.0 keV luminosities in excess of 1039 erg s-1 are identified in a complete sample of 127 nearby galaxies. The sample includes all galaxies within 14.5 Mpc above the completeness limits of both the Uppsala Galaxy Catalogue and the Infrared Astronomical Satellite survey. The galaxy sample spans all Hubble types, a four-decade range in mass, 7.5 < log (M/Msun) < 11.4, and in star formation rate, 0.0002 < SFR(Msun yr-1) <= 3.6. ULXs are detected in this sample at rates of one per 3.2 x 1010 Msun, one per ~0.5 Msun yr-1 star formation rate, and one per 57 Mpc3 corresponding to a luminosity density of ~2 x 1037 erg s-1 Mpc-3. At these rates, the authors estimate as many as 19 additional ULXs remain undetected in fainter dwarf galaxies within the survey volume. An estimated 14 objects, or 13%, of the 107 ULX candidates are expected to be background sources. The differential ULX luminosity function shows a power-law slope alpha ~ -0.8 to -2.0 with an exponential cutoff at ~20 x 1039 erg s-1 with precise values depending on the model and on whether the ULX luminosities are estimated from their observed numbers of counts or, for a subset of candidates, from their spectral shapes. Extrapolating the observed luminosity function predicts at most one very luminous ULX, LX ~ 1041 erg s-1, within a distance as small as 100 Mpc. The luminosity distribution of ULXs within the local universe cannot account for the recent claims of luminosities in excess of 2 x 1041 erg s-1, requiring a new population class to explain these extreme objects. This table was created by the HEASARC in November 2011 based on an electronic version of Table 1 from the reference paper that was obtained from the ApJ web site. This is a service provided by NASA HEASARC . 2011ApJ...741...49S https://heasarc.gsfc.nasa.gov/W3Browse/all/ulxngcat.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=ulxngcat& GET text/xml 180 99999 true 178.15566667 -2.46863889 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=ulxngcat GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_ulxngcat&Action=More+Options&Action=Parameter+Search&ConeAdd=1 CHANDRA 0.0166666666666667 X-ray public ulxngcat Ultraluminous X-Ray Sources in Nearby Galaxies Catalog name Source Designation of the ULX Candidate meta.id;meta.main char nullable ra Right Ascension of the ULX Candidate degree pos.eq.ra;meta.main double nullable dec Declination of the ULX Candidate degree pos.eq.dec;meta.main double nullable galaxy_name Designation of the ULX Host Galaxy meta.id char nullable radial_fraction Separation of ULX from Center r25 pos.angDistance double nullable counts Aperture-Corrected X-Ray Source Counts ct phot;em.X-ray double nullable snr X-Ray Detection Signal-to-Noise Ratio stat.snr;phot;em.X-ray double nullable lx_cts Unabsorbed 0.3-10.0 keV Luminosity Using Fixed Conversion Rate erg/s phys.luminosity;em.X-ray double nullable lx_fit Unabsorbed 0.3-10.0 keV Luminosity Using Spectral Model Fit erg/s phys.luminosity;em.X-ray double nullable lii Galactic Longitude of the ULX Candidate degree pos.galactic.lon double nullable obsid Identifier of the Chandra or XMM-Newton Pointing meta.id;obs char nullable bii Galactic Latitude of the ULX Candidate degree pos.galactic.lat double nullable ref_source Reference Code for the ULX Candidate meta.ref short nullable "distance" Distance to the ULX Host Galaxy Mpc pos.distance 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