Supermassive black holes (smbh) at the centers of galaxies become active when they devour matter from around them at a high rate. Much is still unknown about how matter around active galactic nuclei…

This is a $45,106.60 grant award to Trustees of Dartmouth College, a prestigious Ivy League institution, for a research project titled "Supermassive Black Holes (SMBH) at the Centers of Galaxies". The project aims to study the regulation of matter around active galactic nuclei, leveraging data from multiple NASA space missions including XMM, Chandra, Swift-BAT, and NuSTAR, as well as multiwavelength data from other observatories. This grant supports the NASA science goal of probing the nature of black holes, dark energy, dark matter, and gravity. The award is part of the Astrophysics Data Analysis Program and does not have a set-aside designation. As a leading research university, Dartmouth College has extensive experience conducting federally-funded projects across scientific disciplines, often in collaboration with other academic and industry partners.

Supermassive black holes (smbh) at the centers of galaxies become active when they devour matter from around them at a high rate. Much is still unknown about how matter around active galactic nuclei (AGN) is regulated. The pure unified model posits that the differences in the observed signatures from AGN occur only due to differences in observers viewing angles. The receding torus model offers an explanation for the observed decrease in obscured AGN fraction with luminosity (i.e., the dust sublimation radius is higher for more luminous AGN, making them unobscured in many more viewing angles). More recently, the swift-BAT 70-month survey, which observed the local universe in high-energy x-rays, and produced one of the most unbiased samples of obscured and unobscured AGN, has found that the obscured fraction does not decrease with increasing luminosity, but with increasing accretion rate (that is, eddington ratio l_e /propto lbol/m_BH). These findings point to l_e being more fundamentally tied to torus structure than luminosity, and IT is known as the radiation regulated unified model. The proposed program directly addresses a major NASA science goal to probe the origin and destiny of our universe, including the nature of black holes, dark energy, dark matter, and gravity. This project has clear significance to the objectives of the astrophysics data analysis program, as IT makes use of the archives of multiple NASA space missions. Moreover, IT will make extensive use of NASA s XMM, chandra, swift-BAT and nustar surveys, as well as multiwavelength data from hubble, galex, sdss, spitzer and wise, to carry out a rigorous study of the black hole accretion rate distribution and its redshift evolution.