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

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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.