The Search for Binary Supermassive Black Holes among Quasars with Offset Broad Lines Using the Very Long Baseline Array
The Search for Binary Supermassive Black Holes among Quasars with Offset Broad Lines Using the Very Long Baseline Array
复制标题
DOI：
10.3847/1538-4357/abfa9a
复制
发表时间：
2021-03
期刊：
影响因子：
--
通讯作者：
Peter Breiding;S. Burke-Spolaor;M. Eracleous;T. Bogdanovi'c;T. Lazio;J. Runnoe;S. Sigurdsson
中科院分区：
文献类型：
--
作者：
Peter Breiding;S. Burke-Spolaor;M. Eracleous;T. Bogdanovi'c;T. Lazio;J. Runnoe;S. Sigurdsson
在之前的几项研究中，已经发现了类星体的宽发射线，相对于宿主星系静止坐标系的速度偏移为1000 km s−1。对于这些速度偏移宽线的起源，一个主要的假设是一个双超大质量黑洞（SMBH）的动力学。我们提出了34个类星体的高分辨率无线电成像，显示这些速度偏移宽线与甚长基线阵列（VLBA），旨在寻找证据的推定二进制SMBH（如双无线电核心），并测试竞争的物理模型。在实现5σ检测限后，我们从VLBA成像中检测到了一半的目标样品。虽然我们不解决双射电源的任何目标，我们得到的假设下，仍然存在于我们的VLBA角分辨率限制的无线电发射的二进制的所有检测到的源的瞬时投影分离的限制。我们还评估了无线电发射的同伴SMBH存在于我们的角分辨率限制之外的可能性，但它的无线电光度太弱，无法在VLBA数据中产生可检测的信号。此外，我们将这些数据提供的精确天空位置与SDSS和Gaia DR 2源目录的光学位置进行了比较。我们发现，预计无线电/光学分离的顺序为1000 pc的三个类星体。最后，我们将探讨未来的多波长运动与光学，无线电和X射线天文台可以帮助进一步区分竞争的物理模型。
In several previous studies, quasars exhibiting broad emission lines with ≳1000 km s−1 velocity offsets with respect to the host galaxy rest frame have been discovered. One leading hypothesis for the origin of these velocity-offset broad lines is the dynamics of a binary supermassive black hole (SMBH). We present high-resolution radio imaging of 34 quasars showing these velocity-offset broad lines with the Very Long Baseline Array (VLBA), aiming to find evidence for the putative binary SMBHs (such as dual radio cores), and testing the competing physical models. We detect exactly half of the target sample from our VLBA imaging, after implementing a 5σ detection limit. While we do not resolve double radio sources in any of the targets, we obtain limits on the instantaneous projected separations of a radio-emitting binary for all of the detected sources under the assumption that a binary still exists within our VLBA angular resolution limits. We also assess the likelihood that a radio-emitting companion SMBH exists outside of our angular resolution limits, but its radio luminosity is too weak to produce a detectable signal in the VLBA data. Additionally, we compare the precise sky positions afforded by these data to optical positions from both the SDSS and Gaia DR2 source catalogs. We find projected radio/optical separations on the order of ∼10 pc for three quasars. Finally, we explore how future multi-wavelength campaigns with optical, radio, and X-ray observatories can help discriminate further between the competing physical models.