Evidence of absorption due to highly ionized gas in the radio-quiet quasar PG 1114+445

被引:19
作者
George, IM [1 ]
Nandra, K
Laor, A
Turner, TJ
Fiore, F
Netzer, H
Mushotzky, RF
机构
[1] NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 660, Greenbelt, MD 20771 USA
[2] Univ Space Res Assoc, Washington, DC USA
[3] Technion Israel Inst Technol, Dept Phys, IL-32000 Haifa, Israel
[4] Osservatorio Astron Roma, I-00040 Rome, Italy
[5] BeppoSAX Sci Data Ctr, I-00131 Rome, Italy
[6] Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Sch Phys & Astron, IL-69978 Tel Aviv, Israel
关键词
galaxies; active; nuclei; Seyfert quasars; individual; (PG; 1114+445); X-rays;
D O I
10.1086/304998
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present results on the X-ray spectrum of the quasar PG 1114+445 from an ASCA observation performed in 1996 June and a ROSAT observation performed 3 years earlier. We show that good agreement between all the data sets can be obtained if the underlying continuum in the 0.2-10 keV band is assumed to be a power law (photon index Gamma similar or equal to 1.8) absorbed by photoionized material. The ionized gas imprints deep absorption edges in the observed spectrum less than or similar to 2 keV due to O VII, and O VIII, from which we determine its column density (similar to 2 x 10(22) cm(-2)) and ionization parameter (U-X similar to 0.1) to be similar to that observed in Seyfert 1 galaxies. Unfortunately, these data do not allow any strong constraints to be placed on the location of or the solid angle subtended by the material at the ionizing source. We also find evidence of absorption in the Fe K-shell band in excess of that predicted from the lower energy features. This implies an Fe/O abundance ratio similar to 10 times the cosmic value, or an additional screen of more highly ionized gas, possibly outflowing from the nucleus. We briefly compare our results with those obtained from other active galaxies.
引用
收藏
页码:508 / 514
页数:7
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