Radio Emission from Intermediate Mass Black Holes: Evolution with Accretion Rate

黑洞在宇宙中无处不在，质量范围很大。一些黑洞的质量比太阳大几倍，是在一颗大质量恒星的核心在其生命结束时坍塌时形成的。在星系中心还发现了其他黑洞。它们通常比太阳的质量大数百万倍或数亿倍，被称为超大质量黑洞(SMBH)。来自里诺内华达大学的一个团队将通过研究质量介于恒星和SMBH之间的黑洞来更好地了解SMBH的增长。这些中间质量黑洞(IMBH)是至关重要的，因为人们认为IMBH要么与其他黑洞合并，要么在它们附近吸积物质--尘埃、气体和恒星--从而成长为SMBH。具体地说，该团队将调查缓慢积累的IMBH和快速积累的IMBH的无线电辐射有何不同。该小组将与当地教育组织合作，为K-12学校开发外展材料。外展材料将基于学生对大盆地天文台的观察，大盆地天文台是一台位于内华达州东部的0.7米机器人望远镜。此外，还将对两名研究生进行无线电干涉测量技术培训。该项目由NSF AST和已建立的激励竞争性研究计划(EPSCoR)共同资助。在这个项目中，该小组将仔细检查IMBH的无线电辐射。利用卡尔·G·詹斯基甚大阵列的射电数据，结合现有的多波长信息，他们将：(1)揭示快速吸积的IMBH(爱丁顿比为1%)的吸积状态和射电发射机制。(2)确定弱吸积IMBH(爱丁顿比为1%)是否发射辐射功率与当前预期相符的射电急流，以验证当前基于无线电的IMBH选择技术。(3)比较快速和弱吸积系统之间的无线电辐射，以调查IMBH是否遵循与它们质量较低和质量较高的近亲(即分别为STELLAR和SMBH)相似的模式。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Black holes are ubiquitous in the universe and have a wide range of masses. Some black holes are a few times more massive than the sun and are formed when the core of a massive star collapses at the end of its life. Other black holes are found in the centers of galaxies. These are typically millions or hundreds of millions times more massive than the sun and are known as Super Massive Black Holes (SMBHs). A team from the University of Nevada, Reno, will better understand the growth of SMBH by studying black holes that have masses intermediate between stellar and SMBHs. These Intermediate Mass Black Holes (IMBHs) are crucial because it is thought that IMBH grow into SMBH either by merging with other black holes or accreting material - dust, gas, and stars - in their immediate vicinity. Specifically, the team will investigate how the the radio emission differs in IMBHs that are accreting slowly vs. those that are rapidly accreting. The team will work with local education organizations to develop outreach materials for K-12 schools. The outreach materials will be based on student observations with the Great Basin Observatory, an 0.7m robotic telescope in eastern Nevada. In addition, two graduate students will be trained in radio interferometry techniques. This project is jointly funded by NSF AST and by the Established Program to Stimulate Competitive Research (EPSCoR). In this project, the team will scrutinize radio emission from IMBHs. Using radio data from the Karl G Jansky Very Large Array, in conjunction with existing multiwavelength information, they will: (1) Reveal the accretion state and radio emission mechanisms of rapidly accreting IMBHs (Eddington ratios 1%). (2) Determine if weakly accreting IMBHs (Eddington ratios 1%) launch radio jets with radiative powers matching current expectations, to validate current radio-based IMBH selection techniques. (3) Compare radio emission between the rapid and weak accretion regimes to investigate if IMBHs follow similar patterns as their lower- and higher-mass cousins (i.e., stellar and SMBH, respectively).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.