2005MNRAS.362L..20I -
Mon. Not. R. Astron. Soc., 362, L20-L24 (2005/September-1)
X-rays from the Type II quasar in the hyperluminous infrared galaxy IRAS F15307+3252.
IWASAWA K., CRAWFORD C.S., FABIAN A.C. and WILMAN R.J.
Abstract (from CDS):
We report the detection of X-ray emission from the hyperluminous infrared galaxy IRAS F15307+3252 at z= 0.93 and its properties obtained from XMM-Newton observations. Although the X-ray emission is very faint and the data are noisy, a prominent line-like feature in the observed 3-4 keV range is inferred from both photometric and spectroscopic techniques. It indicates an X-ray spectrum dominated by 6.4-keV Fe Kα emission and the presence of a Compton-thick active galactic nucleus. Our estimate of the luminosity of the illuminating source (L2–10keV≥ 1x1045/ergs), required to produce the observed Fe Kα emission in reflection from cold matter, means that the hidden quasar nucleus accounts for a significant fraction of the large bolometric luminosity. The soft X-ray emission below 2 keV is found to be spatially extended and probably of a separate origin. The temperature and bolometric luminosity (kT≃ 2 keV and LCLbol≃ 1x1044/ergs) obtained from a thermal spectrum place this X-ray source on the L-TXrelation of galaxy clusters. The possible association with a galaxy cluster can be added to the list of remarkable similarities between IRAS F15307+3252 and another hyperluminous infrared galaxy IRAS 09104+4109 (z= 0.44), both of which have bolometric luminosities dominated by hidden quasar nuclei. Our result on IRAS F15307+3252 illustrates how difficult it is to detect Compton-thick Type II quasars at z= 1, particularly if their bolometric outputs do not rival the hyperluminous population.
Abstract Copyright:
2005 RAS
Journal keyword(s):
galaxies: individual: IRAS F15307+3252 - infrared: galaxies - X-rays: galaxies - X-rays: galaxies: clusters
CDS comments:
In Inroduction : IRAS P09104+4101 is a misprint for IRAS 09104+4109.
Simbad objects:
6
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