A COMPLETE SAMPLE OF ULTRALUMINOUS X-RAY SOURCE HOST GALAXIES

Journal Article · Tue Nov 01 04:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/741/1/49; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21612723

Swartz, Douglas A ^[1]; Soria, Roberto ^[2]; Tennant, Allyn F ^[3]; Yukita, Mihoko ^[4]

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1. Universities Space Research Association, NASA Marshall Space Flight Center, VP62, Huntsville, AL 35812 (United States)
2. Curtin Institute of Radio Astronomy, Curtin University, 1 Turner Avenue, Bentley, WA 6102 (Australia)
3. Space Science Office, NASA Marshall Space Flight Center, VP62, Huntsville, AL 35812 (United States)
4. Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487 (United States)

One hundred seven ultraluminous X-ray sources (ULXs) with 0.3-10.0 keV luminosities in excess of 10{sup 39} erg s{sup -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/M{sub sun}) < 11.4, and in star formation rate, 0.0002 < SFR(M{sub sun} yr{sup -1}) {<=} 3.6. ULXs are detected in this sample at rates of one per 3.2 Multiplication-Sign 10{sup 10} M{sub sun}, one per {approx}0.5 M{sub sun} yr{sup -1} star formation rate, and one per 57 Mpc{sup 3} corresponding to a luminosity density of {approx}2 Multiplication-Sign 10{sup 37} erg s{sup -1} Mpc{sup -3}. At these rates we 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} {approx} -0.8 to -2.0 with an exponential cutoff at {approx}20 Multiplication-Sign 10{sup 39} erg s{sup -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, L{sub X} {approx} 10{sup 41} erg s{sup -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 Multiplication-Sign 10{sup 41} erg s{sup -1}, requiring a new population class to explain these extreme objects.

• OSTI ID: 21612723
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 741; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
CATALOGS
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
DISTANCE
DISTRIBUTION
DOCUMENT TYPES
EVOLUTION
GALACTIC EVOLUTION
GALAXIES
LUMINOSITY
MASS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
SATELLITES
SPATIAL DISTRIBUTION
STAR EVOLUTION
STARS
UNIVERSE
X-RAY GALAXIES