TY - JOUR
T1 - ASCA spectroscopy of IRAS 23060 + 0505
T2 - Penetrating the torus of a type 2 quasar with X-rays
AU - Brandt, W. N.
AU - Fabian, A. C.
AU - Takahashi, K.
AU - Fujimoto, R.
AU - Yamashita, A.
AU - Inoue, H.
AU - Ogasaka, Y.
PY - 1997
Y1 - 1997
N2 - We report on a pointed ASCM observation of the powerful (Lbol ≈ 1.3 × 1046 erg s-1) type 2 infrared luminous galaxy IRAS 23060 + 0505. This galaxy has been the subject of detailed spectroscopic and spectropolarimetric studies which have revealed a hidden broad-line region and have been used to construct a detailed model of the light paths in this source. Our observation detects IRAS 23060 + 0505 in the X-ray band for the first time and complements the optical and infrared studies. We detect hard X-ray emission that can be modelled as a power law with a 2-10 keV luminosity of 1.5 × 1044 erg s-1, thereby verifying the existence of an accreting supermassive black hole in IRAS 23060 + 0505. The obscuring torus of IRAS 23060 + 0505 appears to be Compton thin along our line of sight, and we measure a column to the nuclear X-ray source of about 8 × 1022 cm-2. Comparison of the X-ray column with the Av=30±4 mag extinction measurement by Young et al. suggests that the torus may have a dust-to-gas ratio rather similar to that in the interstellar medium of the Milky Way. We also find some evidence for iron K-line emission. The apparent X-ray to bolometric luminosity ratio for IRAS 23060 + 0505 is ≲, 1 per cent, a rather low value, and we consider possible explanations for this low ratio.
AB - We report on a pointed ASCM observation of the powerful (Lbol ≈ 1.3 × 1046 erg s-1) type 2 infrared luminous galaxy IRAS 23060 + 0505. This galaxy has been the subject of detailed spectroscopic and spectropolarimetric studies which have revealed a hidden broad-line region and have been used to construct a detailed model of the light paths in this source. Our observation detects IRAS 23060 + 0505 in the X-ray band for the first time and complements the optical and infrared studies. We detect hard X-ray emission that can be modelled as a power law with a 2-10 keV luminosity of 1.5 × 1044 erg s-1, thereby verifying the existence of an accreting supermassive black hole in IRAS 23060 + 0505. The obscuring torus of IRAS 23060 + 0505 appears to be Compton thin along our line of sight, and we measure a column to the nuclear X-ray source of about 8 × 1022 cm-2. Comparison of the X-ray column with the Av=30±4 mag extinction measurement by Young et al. suggests that the torus may have a dust-to-gas ratio rather similar to that in the interstellar medium of the Milky Way. We also find some evidence for iron K-line emission. The apparent X-ray to bolometric luminosity ratio for IRAS 23060 + 0505 is ≲, 1 per cent, a rather low value, and we consider possible explanations for this low ratio.
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U2 - 10.1093/mnras/290.4.617
DO - 10.1093/mnras/290.4.617
M3 - Article
AN - SCOPUS:0001281737
SN - 0035-8711
VL - 290
SP - 617
EP - 622
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 4
ER -