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arXiv 2409.11209astro-ph.GAastro-ph.HE
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赛弗特星系NGC 1566中心超大质量黑洞双星的引力自透镜证据

Evidence for gravitational self-lensing of the central supermassive black hole binary in the Seyfert galaxy NGC 1566

Wolfram Kollatschny, Doron Chelouche

AI总结:

本研究基于NGC 1566的微引力透镜增亮事件,发现其中心可能存在超大质量黑洞双星,推算出透镜黑洞质量、轨道位置及与主黑洞的质量比,为近邻并合黑洞双星探测提供新依据。

摘要:

学界普遍认为,所有大质量星系的中心都存在超大质量黑洞(BH),且两个星系的并合会形成黑洞双星。其中最受关注的是处于并合最终阶段的系统,即轨道间距为秒差距(3.2光年)或亚秒差距量级的双星。这类系统可通过双星自透镜效应被探测到。本文中,我们基于一次微引力透镜增亮事件,报告了活动星系(AGN)NGC 1566中可能存在中心超大质量黑洞双星的探测结果。该增亮事件的光变曲线来自“All Sky Automated Survey for SuperNovae(全天超新星自动巡天)”的观测,持续时间为2017年初至2020年初。其陡峭对称的光变曲线及形态,与活动星系核的常规随机涨落差异显著,但可通过最优拟合的标准微引力透镜光变曲线很好地复现。基于该光变曲线,我们推导出155天的特征时标。增亮期间,连续谱与宽发射线强度均发生变化,但窄发射线无变化,这表明透镜天体在宽线区(BLR)与窄线区(NLR)之间绕活动星系核中心运行,即距离约为250光天量级。该光变曲线可由质量为5×10^5倍太阳质量(M_solar)的黑洞透镜复现,这意味着其与中心活动星系核的质量比约为1:10。

英文摘要:

It is generally accepted that all massive galaxies host supermassive black holes (BHs) in their center and that mergers of two galaxies lead to the formation of BH binaries. The most interesting among them comprise the mergers in their final state, that is to say with parsec (3.2 light years) or sub-parsec orbital separations. It is possible to detect these systems with binary self-lensing. Here we report the potential detection of a central supermassive BH binary in the active galaxy (AGN) NGC1566 based on a microlensing outburst. The light curve of the outburst - based on observations with the All Sky Automated Survey for SuperNovae - lasted from the beginning of 2017 until the beginning of 2020. The steep symmetric light curve as well as its shape look very different with respect to normal random variations in AGN. However, the observations could be easily reproduced with a best-fit standard microlensing light curve. Based on the light curve, we derived a characteristic timescale of 155 days. During the outburst, the continuum as well as the broad line intensities varied; however, the narrow emission lines did not. This is an indication that the lensing object orbits the AGN nucleus between the broad line region (BLR) and the narrow line region (NLR), that is, at a distance on the order of 250 light days. The light curve can be reproduced by a lens with a BH mass of 5*10^{5} M_solar. This implies a mass ratio to the central AGN on the order of 1 to 10.

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。

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