CAREER: Direct Tests of Black Hole Accretion Rate Prescriptions

A galaxy can be completely transformed by a black hole, the huge energy source at its center. Computer simulations help us understand the physics that shapes galaxies. However, even the most complex simulations today need to guess what is going on at very small scales. This project uses new state-of-the-art observations to look at those small scales. These observations will test the equations used to describe how black holes grow. Understanding this aspect of black holes will show how they change their host galaxies. The investigator will also lead efforts to recruit minority students into physics and astronomy by partnering with existing bridge programs. This program will also support current students through mentorship and a new course on basic physics, math, and logic skills. By combining near-infrared adaptive optics-assisted integral field spectroscopy and long-baseline interferometry, using NSF’s ALMA telescope, to obtain high resolution images, this program will measure key properties at sub-10pc resolution around a broad range of active black holes. The interferometric observations will measure the distribution of carbon monoxide, CO, which traces cold gas in this region. These measurements provide the inputs for standard sub-grid prescriptions relating to black hole accretion rates, allowing predictions of, for a given black hole, what the accretion rate would be if that prescription were the dominant one. These systems also have existing hard-X-ray observations and modeling to provide the actual accretion rate. Putting these two together will identify which black hole accretion rate prescriptions are reasonable in which regimes, and produce recommendations for galaxy evolution simulations. 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.