Testing the seyfert unification theory: Chandra HETGS observations of NGC 1068

被引:108
作者
Ogle, PM [1 ]
Brookings, T
Canizares, CR
Lee, JC
Marshall, HL
机构
[1] Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA
[2] MIT, Ctr Space Res, Cambridge, MA 02139 USA
关键词
galaxies : active; galaxies : individual : NGC 1068; X-rays : galaxies;
D O I
10.1051/0004-6361:20021647
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present spatially resolved Chandra HETGS observations of the Seyfert 2 galaxy NGC 1068. X-ray imaging and high resolution spectroscopy are used to test the Seyfert unification theory. Fe Kalpha emission is concentrated in the nuclear region, as are neutral and ionized continuum reflection. This is consistent with reprocessing of emission from a luminous, hidden X-ray source by the obscuring molecular torus and X-ray narrow-line region (NLR). We detect extended hard X-ray emission surrounding the X-ray peak in the nuclear region, which may come from the outer portion of the torus. Detailed modeling of the spectrum of the X-ray NLR confirms that it is excited by photoionization and photoexcitation from the hidden X-ray source. K-shell emission lines from a large range of ionization states of H-like and He-like N, O, Ne, Mg, Al, Si, S, and Fe XVII-XXIV L-shell emission lines are modeled. The emission measure distribution indicates roughly equal masses at all observed ionization levels in the range log xi = 1-3. We separately analyze the spectrum of an off-nuclear cloud. We find that it has a lower column density than the nuclear region, and is also photoionized. The nuclear X-ray NLR column density, optical depth, outflow velocity, and electron temperature are all consistent with values predicted by optical spectropolarimetry for the region which provides a scattered view of the hidden Seyfert 1 nucleus.
引用
收藏
页码:849 / 864
页数:16
相关论文
共 58 条
[1]   HST ULTRAVIOLET SPECTROPOLARIMETRY OF NGC-1068 [J].
ANTONUCCI, R ;
HURT, T ;
MILLER, J .
ASTROPHYSICAL JOURNAL, 1994, 430 (01) :210-217
[2]   SPECTROPOLARIMETRY AND THE NATURE OF NGC-1068 [J].
ANTONUCCI, RRJ ;
MILLER, JS .
ASTROPHYSICAL JOURNAL, 1985, 297 (02) :621-632
[3]  
BEHAR E, 2001, MASS OUTFLOWS ACTIVE
[4]   The soft X-ray spectrum from NGC 1068 observed with LETGS on Chandra [J].
Brinkman, AC ;
Kaastra, JS ;
van der Meer, RLJ ;
Kinkhabwala, A ;
Behar, E ;
Kahn, SM ;
Paerels, FBS ;
Sako, M .
ASTRONOMY & ASTROPHYSICS, 2002, 396 (03) :761-772
[5]   Laboratory measurements and modeling of the Fe XVII X-ray spectrum [J].
Brown, GV ;
Beiersdorfer, P ;
Liedahl, DA ;
Widmann, K ;
Kahn, SM .
ASTROPHYSICAL JOURNAL, 1998, 502 (02) :1015-1026
[6]   Laboratory measurements and identification of the Fe XVIII-XXIV L-shell X-ray line emission [J].
Brown, GV ;
Beiersdorfer, P ;
Liedahl, DA ;
Widmann, K ;
Kahn, SM ;
Clothiaux, EJ .
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 2002, 140 (02) :589-607
[7]   The ionization structure of the narrow-line region of NGC 1068 and its relationship to the extended radio emission [J].
Capetti, A ;
Axon, DJ ;
Macchetto, FD .
ASTROPHYSICAL JOURNAL, 1997, 487 (02) :560-&
[8]  
CECIL G, 2001, APJ, V568, P627
[9]   The X-ray reflectors in the nucleus of the Seyfert galaxy NGC 1068 [J].
Colbert, EJM ;
Weaver, KA ;
Krolik, JH ;
Mulchaey, JS ;
Mushotzky, RF .
ASTROPHYSICAL JOURNAL, 2002, 581 (01) :182-196
[10]   Resolved spectroscopy of the narrow-line region in NGC 1068: Kinematics of the ionized gas [J].
Crenshaw, DM ;
Kraemer, SB .
ASTROPHYSICAL JOURNAL, 2000, 532 (02) :L101-L104