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Physics & Astronomy - Astronomy Seminar - Tonima Ananna, Yale University

Title: "The Accretion History of AGN: Supermassive Black Hole Population Synthesis Model"

Tuesday, October 30, 2018
2:00pm – 3:00pm
Wilder 202
Intended Audience(s): Public
Categories: Lectures & Seminars

Abstract:

As matter accretes onto the central supermassive black holes in Active Galactic Nuclei (AGN), X-rays are emitted. We present a population synthesis model that accounts for the summed X-ray emission from growing black holes;  modulo the efficiency of converting mass to X-rays, this is effectively a record of the accreted mass. We need this population synthesis model to reproduce observed constraints from X-ray surveys: the X-ray number counts, the observed fraction of Compton-thick AGN [log(N_H/cm^(-2)) > 24] and the spectrum of the Cosmic X-ray "background" (CXB), after accounting for selection biases. Over the past decade, X-ray surveys by XMM-Newton, Chandra, NuSTAR and Swift-BAT have provided greatly improved observational constraints. We find that no existing X-ray luminosity function (XLF) consistently reproduces all these observations. We take the uncertainty in AGN spectra into account, and use a neural network to compute an XLF that fits all observed constraints, including observed Compton-thick number counts and fractions. This new population synthesis model suggests that, intrinsically, 50+/-9% (56+/-7%) of all AGN within z of 0.1 (1.0) are Compton-thick.
 
 
 
For more information, contact:
Tressena Manning
tressena.a.manning@dartmouth.edu
603-646-2854
Permanent URL to this event: https://physics.dartmouth.edu/events/event?event=53722

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