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arXiv 1105.3653astro-ph.HE
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射电观测盲探测并合超大质量黑洞

Blindly Detecting Merging Supermassive Black Holes with Radio Surveys

David L. Kaplan, Richard O'Shaughnessy, Alberto Sesana, Marta Volonteri

摘要:

超大质量黑洞大概是在整个宇宙时间里通过无数次的合并而成长起来的。在每一次合并过程中,超大质量黑洞双星都被一个环绕双星的吸积盘所包围,这个吸积盘施加了一个显著的磁场(对于1 e8 Msun的双星来说,这个磁场约为1 e4 G)。双星在磁场中的运动将把磁场能量转化为坡印廷通量,其光度约为1 e43 erg/s(B/1 e4 G)^2(M/1 e8 Msun)^2,其中一些可能以频率接近1 GHz的同步辐射形式出现,这正是当前和计划中的宽场射电观测所要进行的。我们发现,许多合并的短时间尺度将限制他们的可探测性与大多数计划的盲测<1每年在整个天空,独立的发射过程和通量分布的细节。包括对无线电通量的乐观估计使得检测的可能性更小,整个天空每年的合并<1次。然而,宽场无线电仪器可能能够定位合并前通过引力波识别的系统。此外,无线电巡天可能能够探测到双星运动产生的较弱的辐射,因为它在合并之前受到自旋轨道进动和螺旋运动的调制。

英文摘要:

Supermassive black holes presumably grow through numerous mergers throughout cosmic time. During each merger, supermassive black hole binaries are surrounded by a circumbinary accretion disk that imposes a significant (~1e4 G for a binary of 1e8 Msun) magnetic field. The motion of the binary through that field will convert the field energy to Poynting flux, with a luminosity ~1e43 erg/s (B/1e4 G)^2 (M/1e8 Msun)^2, some of which may emerge as synchrotron emission at frequencies near 1 GHz where current and planned wide-field radio surveys will operate. We find that the short timescales of many mergers will limit their detectability with most planned blind surveys to <1 per year over the whole sky, independent of the details of the emission process and flux distribution. Including an optimistic estimate for the radio flux makes detection even less likely, with <1 mergers per year over the whole sky. However, wide-field radio instruments may be able to localize systems identified in advance of merger by gravitational waves. Further, radio surveys may be able to detect the weaker emission produced by the binary's motion as it is modulated by spin-orbit precession and inspiral well in advance of merger.

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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