arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1303.2630astro-ph.HE
收藏

Arp 220中的两个康普顿厚度的活动核?

Two Compton-Thick Active Nuclei in Arp 220?

Alessandro Paggi, Giuseppina Fabbiano, Guido Risaliti, Junfeng Wang, Martin Elvis

摘要:

Chandra-ACIS对ULIRG合并Arp 220的亚像素分辨率的窄带光谱成像强烈表明两个康普顿厚的核,空间上与红外和无线电发射的核簇一致,并且相隔1”(约365 pc,距离为76 Mpc)。这些以前未被探测到的高度模糊的活动星系核--西(W)和东(E)--在6-7 keV波段被成像,并与相邻的源分离,在那里Fe-K线占主导地位。西方的原子核也在7 keV以上的能量下被探测到。我们估计两个源的铁钾等效宽度约为1 keV或可能更大,并观测到2-10 keV的亮度L_X < 3.2 x 10^40 erg/s(W)和<1.3 x 10^40 erg/s(E)。根据观测到的Fe-K线的亮度{,并在XMM-牛顿光谱的基础上假设其中40%可能来自6.4 keV的分量,我们估算出2-10 keV的本征亮度L_X ~ 1 x 10^42 erg/s(W)和L_X ~ 0.4 x 10^42 erg/s(E)。推断的X射线光度至少比从Arp 220的辐射光度的纯恒星暴所预期的高3倍。对于一个典型的活动星系核SED,辐射热光度分别为5.2 x 10^43 erg/s(W)和2 x 10^42 erg/s(E)。

英文摘要:

Narrow-band spectral imaging with sub-pixel resolution of the Chandra-ACIS archival observation of the ULIRG merger Arp 220 strongly suggests two Compton thick nuclei, spatially coincident with the infrared and radio emitting nuclear clusters, and separated by 1" (~ 365 pc at a distance of 76 Mpc). These previously undetected highly obscured AGNs - West (W) and East (E) - are imaged, and separated from neighboring sources, in the 6-7 keV band, where the Fe-K lines dominate the emission. The western nucleus is also detected at energies above 7 keV. We estimate Fe-K equivalent width ~ 1 keV or possibly greater for both sources, and observed 2-10 keV luminosities L_X < 3.2 x 10^40 erg/s (W) and <1.3 x 10^40 erg/s (E). From the observed Fe-K lines luminosities{, and assuming on the basis of the XMM-Newton spectrum that 40% of this may be from the 6.4 keV component, we evaluate 2-10 keV intrinsic luminosities L_X ~ 1 x 10^42 erg/s (W) and L_X ~ 0.4 x 10^42 erg/s (E). The inferred X-ray luminosity is at least a factor of 3 higher than that expected from a pure starburst with the bolometric luminosity of Arp 220. For a typical AGN SED the bolometric luminosities are 5.2 x 10^43 erg/s (W) and 2 x 10^42 erg/s (E).

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。

↑