arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1107.3370astro-ph.HE
收藏

Fermi-LAT观测的宽线射电星系:GeV Gamma-Ray发射的起源

Broad Line Radio Galaxies Observed with Fermi-LAT: The Origin of the GeV Gamma-Ray Emission

J. Kataoka, L. Stawarz, Y. Takahashi, C. C. Cheung, M. Hayashida, P. Grandi, T. H. Burnett, A. Celotti, S. J. Fegan, P. Fortin, K. Maeda, T. Nakamori, G. B. Tay… 展开作者

J. Kataoka, L. Stawarz, Y. Takahashi, C. C. Cheung, M. Hayashida, P. Grandi, T. H. Burnett, A. Celotti, S. J. Fegan, P. Fortin, K. Maeda, T. Nakamori, G. B. Taylor, G. Tosti, S. W. Digel, W. McConville, J. Finke, F. D'Ammando

摘要:

利用费米大天区望远镜(LAT)两年的观测数据,对18个宽线射电星系(BLRG)的γ射线辐射进行了详细的研究。我们证实了先前报道的3C 120和3C 111在GeV光子能量范围内的检测;详细研究了所观察到的伽马射线发射的时间特性,揭示了另外两个源中可能的通量变化。然而,在所考虑的数据集中没有发现其他BLRG的统计学显著的伽马射线检测。虽然研究的样本量很小,但似乎将3C 111和3C 120与尚未在伽马射线中检测到的BLRG区分开来的是特别强的核射电通量。这一发现,连同指示的伽马射线通量的变化和一些其他参数,表明GeV的发射BLRG最有可能占主导地位的相对论性喷流在中间视角观察到的光束辐射。在本文中,我们还分析了一个高吸积率的赛弗特1星系的比较样本,这可以被认为是无线电安静的BLRGs的对应物,并发现没有检测到伽马射线。一个简单的唯象混合模型应用于所讨论的射电强和射电静1型活动星系的宽带辐射表明,核喷流对吸积物质的相对贡献平均为BLRG> 1%,而Seyfert 1星系<0.1%。

英文摘要:

We report on a detailed investigation of the gamma-ray emission from 18 broad line radio galaxies (BLRGs) based on two years of Fermi Large Area Telescope (LAT) data. We confirm the previously reported detections of 3C 120 and 3C 111 in the GeV photon energy range; a detailed look at the temporal characteristics of the observed gamma-ray emission reveals in addition possible flux variability in both sources. No statistically significant gamma-ray detection of the other BLRGs was however found in the considered dataset. Though the sample size studied is small, what appears to differentiate 3C 111 and 3C 120 from the BLRGs not yet detected in gamma-rays is the particularly strong nuclear radio flux. This finding, together with the indications of the gamma-ray flux variability and a number of other arguments presented, indicate that the GeV emission of BLRGs is most likely dominated by the beamed radiation of relativistic jets observed at intermediate viewing angles. In this paper we also analyzed a comparison sample of high accretion-rate Seyfert 1 galaxies, which can be considered radio-quiet counterparts of BLRGs, and found none were detected in gamma-rays. A simple phenomenological hybrid model applied for the broad-band emission of the discussed radio-loud and radio-quiet type 1 active galaxies suggests that the relative contribution of the nuclear jets to the accreting matter is > 1 percent on average for BLRGs, whilst <0.1 percent for Seyfert 1 galaxies.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑