Fluctuations in the diffuse X-ray background observed with Ginga

被引:22
作者
Butcher, JA
Stewart, GC
Warwick, RS
Fabian, AC
Carrera, FJ
Barcons, X
Hayashida, K
Inoue, H
Kii, T
机构
[1] UNIV CAMBRIDGE,INST ASTRON,CAMBRIDGE CB3 0HA,ENGLAND
[2] UNIV CANTABRIA,INST FIS,CSIC,E-39005 SANTANDER,SPAIN
[3] INST SPACE & ASTRONAUT SCI,SAGAMIHARA,KANAGAWA 229,JAPAN
[4] OSAKA UNIV,DEPT EARTH & SPACE SCI,TOYONAKA,OSAKA 560,JAPAN
关键词
galaxies; active; diffuse radiation; X-rays; general;
D O I
10.1093/mnras/291.3.437
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present Ginga measurements of the spatial fluctuations in the diffuse X-ray background. When combined with earlier results, the new data constrain the extragalactic log N-log S relation in the 2-10 keV energy band to a form close to the Euclidean prediction over the flux range 10(-10)-5 x 10(-13) erg cm(-2) s(-1). The normalization of the 2-10 keV source counts is a factor 2-3 above that derived in the softer 0.3-0.5 keV band from the Einstein Extended Medium Sensitivity Survey, if a spectral conversion is assumed which ignores X-ray absorption intrinsic to the sources. Both this result and the spectral characteristics of the spatial fluctuations are consistent with relatively low-luminosity active galaxies (i.e. L-x<10(44) erg s(-1)) dominating the 2-10 keV source counts at intermediate flux levels. We also use the 'excess variance' of the fluctuations to constrain possible clustering of the underlying discrete sources.
引用
收藏
页码:437 / 445
页数:9
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