658 citations · 9k across the 163 of their papers we have counts for
6 papers · 1 filter
Chandra Grating Spectroscopy of the Seyfert Galaxy Ton S180
T. J. Turner, I. M. George, T. Yaqoob +6
This paper presents results from spectral observations of Ton S180 using Chandra and ASCA. The data confirm the presence of the soft excess but the Chandra LETG spectrum reveals it…
A Broad Fe-Kalpha Emission Line in the X-Ray Spectrum of the Quasar 3C 273
T. Yaqoob, P. J. Serlemitsos
The Fe-K line, an important physical diagnostic in the X-ray spectra of AGN, has been notoriously difficult to measure in the high-luminosity, radio-loud quasar 3C 273 (z=0.158). O…
Variable Iron K-alpha Lines in Seyfert 1 Galaxies
K. A. Weaver, J. Gelbord, T. Yaqoob
We find that variability of the iron K-alpha line is common in Seyfert 1 galaxies. Using data from the ASCA archive for objects that have been observed more than once during the mi…
Physical Diagnostics from a Narrow Fe-Kalpha Emission Line Detected by Chandra in the Seyfert 1 Galaxy NGC 5548
T. Yaqoob, I. M. George, K. Nandra +3
We report the detection of a narrow Fe-K emission line in the Seyfert 1 galaxy NGC 5548 with the Chandra High-Energy Transmission Gratings. In the galaxy frame we measure a center…
What Kind of Obscured AGN Make the Cosmic X-ray Background?
T. Yaqoob
While it is understood that the origin of the Cosmic X-ray Background (CXRB) can be explained in terms of a combination of obscured and unobscured AGN, the identity of these obscur…
Iron K line Variability in the Low-Luminosity AGN NGC 4579
Y. Terashima, L. C. Ho, A. F. Ptak +4
We present results of new ASCA observations of the low-luminosity AGN (LLAGN) NGC 4579 obtained on 1998 December 18 and 28, and we report on detection of variability of an iron K e…