COMPTEL OBSERVATIONS OF CENTAURUS A AT MEV ENERGIES IN THE YEARS 1991 TO 1995
COMPTEL OBSERVATIONS OF CENTAURUS A AT MEV ENERGIES IN THE YEARS 1991 TO 1995
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1991 年至 1995 年半人马座 A 在 MEV 能量下的 COMPTEL 观测
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
O. Williams
中科院分区：
文献类型：
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作者：
H. Steinle;K. Bennett;H. Bloemen;W. Collmar;R. Diehl;W. Hermsen;G. Lichti;D. Morris;V. Schönfelder;A. Strong;O. Williams
在1991年至1995年康普顿伽马射线天文台（CGRO）在第一、二、三和四阶段/第四周期进行的观测中，包括射电星系半人马座A在内的天空区域在不同持续时间的15个点中处于康普顿望远镜的宽视场内。在这15个点期间获得的COMPTEL数据的分析显示半一致的位置的Cen A和我们检测到Cen A在两个发射状态（中间和低）。我们的数据不要求，但也不能排除附近X射线源（MS1312.1-4221）的发射对测量的通量有贡献。但是，在COMPTEL观测的第二阶段中，在d 3 - 10 MeV能带中观测到的高通量不太可能是由于这个源的重要贡献。COMPTEL能量范围为0.75 - 30 MeV的光谱与OSSE的半人马座A能量范围为0.05 - 4 MeV的光谱和EGRET的0.1 - 1 GeV数据点一致，这两种仪器也在CGRO上。的光谱形式不同的两个观测到的发射状态，我们推导出的总能带从50 keV至1 GeV的5 - 10 - 42 erg s-1和3 - 10 - 42 erg s-1的各向同性发射中的中间和低的发射状态，分别为射线光度。包括同时期的OSSE和EGRET光谱延伸覆盖的能量范围内，在这个观测近十年，并提出了硬约束模型的射线发射的活动星系核。
During the Compton Gamma-Ray Observatory (CGRO) observations made in Phase I, II, III, and IV/Cycle 4 in the years 1991 to 1995, the region on the sky including the radio galaxy Centaurus A was in the wide eld-of-view of COMPTEL in 15 pointings of various durations. The analysis of the COMPTEL data obtained during these 15pointingsshowsemissionconsistentwiththepositionofCen A and we detected Cen A in two emission states (intermediate and low). Our data do not require, but also cannot rule out, that emission from a nearby X-ray source (MS1312.1-4221) contributes to the measured flux. But it is unlikely, that the high flux observed in the energy ban d3-1 0 MeVduring Phase II of theCOMPTELobservations,isduetoasignicantcontribution of this source. The spectra in the COMPTEL energy range 0.75 - 30 MeV are consistent with the Centaurus A spectra in the energy range 0.05 - 4 MeV from OSSE and the 0.1 - 1 GeV data points from EGRET, both instruments also on board CGRO. The spectral form differs between the two observed emission states and we derive a -ray luminosity in the total energy band from 50 keV to 1 GeV of 5 10 42 erg s 1 and 3 10 42 erg s 1 for isotrop- ical emission in the the intermediate and low emission state, respectively. The inclusion of the contemporaneous OSSE and EGRET spectra stretches the covered energy range in this observations over almost ve decades and puts hard constraints on models for the -ray emission of this AGN.