ULXNGCAT - Ultraluminous X-Ray Sources in Nearby Galaxies Catalog
A Complete Sample of Ultraluminous X-Ray Source Host Galaxies Swartz D.A., Soria R., Tennant A.F., Yukita M. <Astrophys. J., 741, 49 (2011)> =2011ApJ...741...49S
The name of the ULX candidate. The HEASARC created this parameter using the usual Dictionary of Nomenclature of Celestial Objects format, viz., the prefix '[SST2011]" for Swartz, Soria, Tennant 2011 and the J2000.0 equatorial coordinates of the source.
The Right Ascension of the ULX candidate in the selected equinox. This was given in J2000.0 equatorial coordinates to a precision of 0.01 seconds of time in the original table. The accuracy of this is estimated to be ~0.3 arcseconds for a Chandra source (3-5 digit ObsID value) or ~1.5 arcseconds for an XMM-Newton source (10 digit ObsID value).
The Declination of the ULX candidate in the selected equinox. This was given in J2000.0 equatorial coordinates to a precision of 0.1 arcseconds in the original table. The accuracy of this is estimated to be ~0.3 arcseconds for a Chandra source (3-5 digit ObsID value) or ~1.5 arcseconds for an XMM-Newton source (10 digit ObsID value).
The Galactic Longitude of the ULX candidate.
The Galactic Latitude of the ULX candidate.
The designation of the putative ULX host galaxy.
The distance to the putative ULX host galaxy, in megaparsecs. Distances to target galaxies were taken from the critically assessed values used previously in the ULX catalog of Swartz et al. (S04: 2004, ApJS, 154, 519). Otherwise, distances were taken from the recent NED compilation of redshift-independent distances in the following order of preference listed in Section 3.1 of the reference paper: Cepheid period-luminosity relation from the Hubble Key Project results, other Cepheid-based distances, surface brightness fluctuations, the tip of the red giant branch, globular cluster luminosity functions, brightest stars, and the Tully-Fisher relation. Targets not included in the redshift-independent NED compilation or in S04 were assigned distances as listed in the Nearby Galaxies Catalogue (Tully 1988) or, finally, from flow-corrected redshift distances listed in NED, preferring the values corrected for Local Group motions over those using only a single-attractor Virgocentric flow model.
The separation of the ULX candidate from the center of the host galaxy, expressed as a fraction F_D25_of the deprojected galaxy radius in units of half of the major isophotal angular diameter measured at the surface brightness level of 25.0 mag arcsec-2 in blue light.
The observation identifier (ObsID) of the Chandra or XMM-Newton pointing, where 3-5 digit numbers refer to Chandra observations and 10 digit numbers refer to XMM-Newton pointings.
The aperture-corrected X-ray source counts within the detection bandpass: 0.3-6.0 keV for Chandra sources (3-5 digit ObsID values) or 0.5-4.5 keV for XMM-Newton sources (10 digit ObsID values).
The X-ray detection signal-to-noise ratio.
The unabsorbed 0.3-10.0 keV luminosity of the source, in erg s-1, assuming that it is at the distance of the galaxy, estimated from the source counts in the original detection bandpass and using a fixed conversion rate calculated assuming an absorbed power-law spectrum of Gamma = 1.7 and the Galactic column density in the direction of the source.
The unabsorbed 0.3-10.0 keV luminosity of the source, in erg s-1, assuming that it is at the distance of the galaxy, estimated from model fits to the X-ray spectral energy distribution. For sources with >130 counts detected in any observation, this is either newly calculated herein (see Section 3.5 of the reference paper for the full details) or taken from published results in the literature. For results taken from the literature, the intrinsic luminosities were converted from the originally published energy range to the 0.3-10.0 keV bandpass and, where needed, scaled to the distances adopted herein. PIMMS was used for the bandpass conversion and to scale from observed to intrinsic (unabsorbed) fluxes where needed if spectral model fit parameters were provided. The references to published spectral modeling results are listed in the ref_source parameter (q.v.).
This parameter contains a number that indicates the reference from which the spectral fit results for the ULX candidate (quoted in the lx_fit parameter) are taken. The references are coded as follows:
1: Feng & Kaaret 2009, ApJ, 696, 1712; 2: Roberts et al. 2004, MNRAS, 349, 1193; 3: Walton et al. 2011, MNRAS, 414, 1011; 4: Sutton et al. 2011, Astron. Nachr., 332, 362.