Summer Seminar: Joe McEwen and Michael Fausnaugh

November 14, 2016
Tuesday, June 21, 2016 - 11:30am to 12:30pm
4138 PRB
Oval

"FAST-PT: a Novel Algorithm to Calculate Convolution Integrals in Cosmological Perturbation Theory"

Joe McEwen (Physics)

In this talk, I present a newly developed numerical algorithm to perform convolution or mode-coupling integrals that appear in nonlinear cosmological perturbation theory. The algorithm makes use of special function identities to reduce the convolution integral to a one dimensional integral calculable by Fourier transforms. This yields extremely fast performance, enabling mode-coupling integral computations fast enough to embed in Monte Carlo Markov Chain parameter estimation. As a first example of FAST-PT, I presents results for one-loop calculations.

 

"Reverberation Mapping of AGN Accretion Disks"

Michael Fausnaugh (Astronomy)

I will discuss new reverberation mapping results that allow us to investigate the temperature structure of AGN accretion disks. By measuring time-delays between broad-band continuum light curves, we can determine the size of the disk as a function of wavelength, which allows us to map the disk's temperature profile. I will discuss the recent detection of continuum lags in NGC 5548 reported by the AGN STORM project and the implications of these lags for the accretion disk. I will also present results from a 6-month reverberation mapping campaign that has found evidence for continuum lags in several other AGN. Most of these targets do not have previously published black hole masses, and our measurements of these masses allow us to directly compare the inter-band continuum lags with predictions from standard thin-disk theory.

 

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