|SUZAKU MONITORING OF THE IRON K EMISSION LINE IN THE TYPE 1 ACTIVE GALACTIC NUCLEUS NGC 5548|
|Liu, Y; Elvis, M; McHardy, IM; Grupe, D; Wilkes, BJ; Reeves, J; Brickhouse, N; Krongold, Y; Mathur, S; Minezaki, T; Nicastro, F; Yoshii, Y; Zhang, SN; Zhang SN(张双南)
; Elvis, Martin
; Wilkes, Belinda J.
; Brickhouse, Nancy
; Nicastro, Fabrizio] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA
; [Liu, Yuan
; Zhang, Shuang Nan] Tsinghua Univ, Dept Phys, Beijing 100084, Peoples R China
; [Liu, Yuan
; Zhang, Shuang Nan] Tsinghua Univ, Ctr Astrophys, Beijing 100084, Peoples R China
; [McHardy, Ian M.] Univ Southampton, Sch Phys & Astron, Southampton SO17 1BJ, Hants, England
; [Grupe, Dirk] Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA
; [Reeves, James] Univ Keele, Sch Phys & Geog Sci, Astrophys Grp, Keele ST5 5BG, Staffs, England
; [Krongold, Yair] Univ Nacl Autonoma Mexico, Inst Astron, Mexico City 04510, DF, Mexico
; [Mathur, Smita] Ohio State Univ, Dept Astron, Columbus, OH 43210 USA
; [Minezaki, Takeo
; Yoshii, Yuzuru] Univ Tokyo, Sch Sci, Inst Astron, Tokyo 1810015, Japan
; [Zhang, Shuang Nan] Chinese Acad Sci, Inst High Energy Phys, Key Lab Particle Astrophys, Beijing 100049, Peoples R China
; [Zhang, Shuang Nan] Univ Alabama, Dept Phys, Huntsville, AL 35899 USA
|摘要||We present seven sequential weekly observations of NGC 5548 conducted in 2007 with the Suzaku X-ray Imaging Spectrometer (XIS) in the 0.2-12 keV band and Hard X-ray Detector (HXD) in the 10-600 keV band. The iron K alpha line is well detected in all seven observations and K beta line is also detected in four observations. In this paper, we investigate the origin of the Fe K lines using both the width of the line and the reverberation mapping method. With the co-added XIS and HXD spectra, we identify Fe K alpha and K beta line at 6.396(-0.007)(+0.009) keV and 7.08(-0.05)(+0.05) keV, respectively. The width of line obtained from the co-added spectra is 38(-18)(+16) eV (FWHM = 4200(-2000)(+1800) km s(-1)) which corresponds to a radius of 20(-10)(+50) light days, for the virial production of 1.220 x 10(7) M(circle dot) in NGC 5548. To quantitatively investigate the origin of the narrow Fe line by the reverberation mapping method, we compare the observed light curves of Fe K alpha line with the predicted ones, which are obtained by convolving the continuum light curve with the transfer functions in a thin shell and an inclined disk. The best-fit result is given by the disk case with i = 30 degrees which is better than a fit to a constant flux of the Fe K line at the 92.7% level (F-test). However, the results with other geometries are also acceptable (P > 50%). We find that the emitting radius obtained from the light curve is 25-37 light days, which is consistent with the radius derived from the Fe K line width. Combining the results of the line width and variation, the most likely site for the origin of the narrow iron lines is 20-40 light days away from the central engine, though other possibilities are not completely ruled out. This radius is larger than the H beta emitting parts of the broad-line region at 6-10 light days (obtained by the simultaneous optical observation), and smaller than the inner radius of the hot dust in NGC 5548 (at about 50 light days).|
galaxies: individual (NGC 5548)
quasars: emission lines
|学科领域||Astronomy & Astrophysics
|WOS研究方向||Astronomy & Astrophysics
|WOS类目||Astronomy & Astrophysics
Liu, Y,Elvis, M,McHardy, IM,et al. SUZAKU MONITORING OF THE IRON K EMISSION LINE IN THE TYPE 1 ACTIVE GALACTIC NUCLEUS NGC 5548[J]. ASTROPHYSICAL JOURNAL,2010,710(2):1228-1238.
Liu, Y.,Elvis, M.,McHardy, IM.,Grupe, D.,Wilkes, BJ.,...&张双南.(2010).SUZAKU MONITORING OF THE IRON K EMISSION LINE IN THE TYPE 1 ACTIVE GALACTIC NUCLEUS NGC 5548.ASTROPHYSICAL JOURNAL,710(2),1228-1238.
Liu, Y,et al."SUZAKU MONITORING OF THE IRON K EMISSION LINE IN THE TYPE 1 ACTIVE GALACTIC NUCLEUS NGC 5548".ASTROPHYSICAL JOURNAL 710.2(2010):1228-1238.