Multiyear BATSE Earth occultation monitoring of NGC 4151

被引：6

作者：

Parsons, AM ^{[1
]}

Gehrels, N

Paciesas, WS

Harmon, BA

Fishman, GJ

Wilson, CA

Zhang, SN

机构：

[1] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA

[2] Univ Alabama, Huntsville, AL 35899 USA

[3] NASA, Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA

来源：

ASTROPHYSICAL JOURNAL | 1998年 / 501卷 / 02期

关键词：

galaxies : active; galaxies : individual (NGC 4151); galaxies : Seyfert; gamma rays : observations;

D O I：

10.1086/305837

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We report the results of nearly six years of continuous monitoring of the Seyfert galaxy NGC 4151 by the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory (CGRO). Continuous 2154 day (5.9 yr) light curves for NGC 4151 have been derived from Earth occultation analysis of CGRO BATSE data. Fluxes are calculated assuming a cutoff power-law model of the form F(E)= F(E-0)(E/E-0)(-alpha) exp (E-0 - E/E-cutoff). Light curves for the 20-70 and 70-200 keV bands are shown and found to have an average flux of 11 x 10(-3) and 2.3 x 10(-3) photons cm(-2) s(-1), respectively. Evidence for intrinsic source variability is observed with a fractional variation ratio measured at F-var = 0.2 in both the 20-70 and 70-200 keV bands. A systematic difference is found between OSSE 50-150 keV flux measurements of NGC 4151 and simultaneous BATSE flux measurements in the same energy range.

引用

页码：608 / 615

页数：8