Origin of the Galactic ridge X-ray emission

被引:174
作者
Revnivtsev, M.
Sazonov, S.
Gilfanov, M.
Churazov, E.
Sunyaev, R.
机构
[1] Max Planck Inst Astrophys, D-85740 Munich, Germany
[2] Russian Acad Sci, Space Res Inst, Moscow 117997, Russia
关键词
stars : binaries : general; Galaxy : bulge; Galaxy : disk; X-rays : general; X-rays : stars;
D O I
10.1051/0004-6361:20054268
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We analyze a map of the Galactic ridge X-ray emission (GRXE) constructed in the 3-20 keV energy band from RXTE/PCA scan and slew observations. We show that the GRXE intensity follows the Galactic near-infrared surface brightness closely and thus traces the Galactic stellar mass distribution. The GRXE consists of two spatial components that can be identified with the bulge/bar and the disk of the Galaxy. The parameters of these components determined from X-ray data are compatible with those derived from near-infrared data. The inferred ratio of X-ray to near-infrared surface brightness I3-20 keV(10(-11) erg s(-1) cm(-2) deg(-2))/I-3.5 (mu m)(MJy/sr) = 0.26 +/- 0.05, and the ratio of X-ray to near-infrared luminosity L3- 20 keV/L3- 4 (mu m) = (4.1 +/- 0.3) x 10(-5). The corresponding ratio of the 3-20 keV luminosity to the stellar mass is L-x/M = (3.5 +/- 0.5) x 10(27) erg s(-1) M-circle dot(-1) , which agrees within the uncertainties with the cumulative emissivity per unit stellar mass of point X-ray sources in the Solar neighborhood, determined in an accompanying paper (Sazonov et al.). This suggests that the bulk of the GRXE is composed of weak X-ray sources, mostly cataclysmic variables and coronally active binaries. The fractional contributions of these classes of sources to the total X-ray emissivity determined from the Solar neighborhood data can also explain the GRXE energy spectrum. Based on the luminosity function of local X-ray sources we predict that, in order to resolve 90% of the GRXE into discrete sources, a sensitivity limit of similar to 10(-16) erg s(-1) cm(-2) (2-10 keV) will need to be reached in future observations.
引用
收藏
页码:169 / 178
页数:10
相关论文
共 70 条
[1]   THE UNIVERSE AT FAINT MAGNITUDES .1. MODELS FOR THE GALAXY AND THE PREDICTED STAR COUNTS [J].
BAHCALL, JN ;
SONEIRA, RM .
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 1980, 44 (01) :73-110
[2]   A persistent high-energy flux from the heart of the Milky Way:: Integral's view of the Galactic center [J].
Bélanger, G ;
Goldwurm, A ;
Renaud, M ;
Terrier, R ;
Melia, F ;
Lund, N ;
Paul, J ;
Skinner, G ;
Yusef-Zadeh, F .
ASTROPHYSICAL JOURNAL, 2006, 636 (01) :275-289
[3]   The photometric structure of the inner Galaxy [J].
Binney, J ;
Gerhard, O ;
Spergel, D .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1997, 288 (02) :365-374
[4]   X-RAY-EMISSION FROM GALACTIC DISK [J].
BLEACH, RD ;
BOLDT, EA ;
SERLEMITSOS, PJ ;
SCHWARTZ, DA ;
HOLT, SS .
ASTROPHYSICAL JOURNAL, 1972, 174 (02) :L101-+
[5]   DIRECT EVIDENCE FOR A BAR AT THE GALACTIC-CENTER [J].
BLITZ, L ;
SPERGEL, DN .
ASTROPHYSICAL JOURNAL, 1991, 379 (02) :631-638
[6]  
BRADT HV, 1993, ASTRON ASTROPHYS SUP, V97, P355
[7]  
COOKE BA, 1970, IAUS, V37, P280
[8]   Mass models of the Milky Way [J].
Dehnen, W ;
Binney, J .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1998, 294 (03) :429-438
[9]   H I IN THE GALAXY [J].
DICKEY, JM ;
LOCKMAN, FJ .
ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS, 1990, 28 :215-261
[10]   THE WARP OF THE GALACTIC STELLAR DISK DETECTED IN IRAS SOURCE COUNTS [J].
DJORGOVSKI, S ;
SOSIN, C .
ASTROPHYSICAL JOURNAL, 1989, 341 (01) :L13-L16