XMM-Newton observations of four high-z quasars

被引:31
作者
Ferrero, E [1 ]
Brinkmann, W [1 ]
机构
[1] Max Planck Inst Extraterr Phys, Ctr Interdisciplinary Plasma Sci, D-85741 Garching, Germany
关键词
galaxies : active; quasars : general; X-rays : galaxies;
D O I
10.1051/0004-6361:20030275
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present the results of XMM-Newton observations of four high-z quasars, two radio-loud and two radio-quiet. One of the radio-loud objects, PKS 2126-158, clearly shows absorption in excess of the galactic value as claimed before from ASCA and ROSAT observations. For PKS 2149-306 the evidence for excess absorption is only marginal in contrast to previous results. The location of the absorber in PKS 2126-158 is compatible with the redshift of the source. Both, a warm and a cold absorber are allowed by the X-ray data. Both quasars have very flat photon spectra (Gamma less than or similar to 1.5) and the high photon statistics reveal small deviations from a simple power law form. For the two radio-quiet objects, Q 0000-263 and Q 1442 + 2931, we determine, for the first time, reliable spectral parameters. Both quasars have steeper power laws (Gamma similar to 2) and show absorption consistent with the galactic value, similar to radio-quiet quasars at low redshifts. In the case of Q 0000-263 the presence of the damped Lyalpha system (N(HI) similar to 2.6 x 10(21) cm(-2) at z = 3.39) cannot be examined further due to the limited photon statistics in all instruments.
引用
收藏
页码:465 / 476
页数:12
相关论文
共 45 条
[1]   ON THE COSMOLOGICAL EVOLUTION OF THE X-RAY-EMISSION FROM QUASARS [J].
AVNI, Y ;
TANANBAUM, H .
ASTROPHYSICAL JOURNAL, 1982, 262 (02) :L17-L21
[2]   X-RAY-PROPERTIES OF OPTICALLY SELECTED QSOS [J].
AVNI, Y ;
TANANBAUM, H .
ASTROPHYSICAL JOURNAL, 1986, 305 (01) :83-99
[3]   Evidence for ionized accretion discs in five narrow-line Seyfert 1 galaxies [J].
Ballantyne, DR ;
Iwasawa, K ;
Fabian, AC .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2001, 323 (02) :506-516
[4]   INFRARED TO X-RAY SPECTRAL ENERGY-DISTRIBUTIONS OF HIGH-REDSHIFT QUASARS [J].
BECHTOLD, J ;
ELVIS, M ;
FIORE, F ;
KUHN, O ;
CUTRI, RM ;
MCDOWELL, JC ;
RIEKE, M ;
SIEMIGINOWSKA, A ;
WILKES, BJ .
ASTRONOMICAL JOURNAL, 1994, 108 (02) :374-394
[5]  
BECHTOLD J, 2002, P M ACT GAL NUCL CEN
[6]   A DEEP ROSAT SURVEY .1. THE QSO X-RAY LUMINOSITY FUNCTION [J].
BOYLE, BJ ;
GRIFFITHS, RE ;
SHANKS, T ;
STEWART, GC ;
GEORGANTOPOULOS, I .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1993, 260 (01) :49-58
[7]  
Brinkmann W, 1997, ASTRON ASTROPHYS, V319, P413
[8]  
BRINKMANN W, 1995, ASTRON ASTROPHYS SUP, V109, P147
[9]   ASCA and ROSAT X-ray spectra of high-redshift radio-loud quasars [J].
Cappi, M ;
Matsuoka, M ;
Comastri, A ;
Brinkmann, W ;
Elvis, M ;
Palumbo, GGC ;
Vignali, C .
ASTROPHYSICAL JOURNAL, 1997, 478 (02) :492-510
[10]   The absorption spectrum of the QSO PKS 2126-158 (zem=3.27) at high resolution [J].
D'Odorico, V ;
Cristiani, S ;
D'Odorico, S ;
Fontana, A ;
Giallongo, E .
ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES, 1998, 127 (02) :217-232