Collin Dabbieri


I'm a second year graduate student at Vanderbilt University, in the department of Physics and Astronomy. I'm working with Professor Jessie Runnoe studying the variability of Sloan Digital Sky Survey Quasars, in an effort to better understand the dynamics of the Broad Line Region. To this end, I'm writing a spectral decomposition model to fit all Sloan quasar spectra with redshifts that can see Hβ. I'll use the decompositions to separate broad Hβ from the rest of each quasars flux. This will allow me to fit changes in broad Hβ radial velocity for quasars with more than one spectral observation. Understanding how Hβ radial velocities change over time will help us better understand the dynamics of the Broad Line Region.

As an undergraduate, I worked with Professor Karen Leighly at the University of Oklahoma studying Broad Absorption Line Quasars. I helped with the development of the forward modelling spectral synthesis tool SimBAL, which uses MCMC to recover robust parameter estimates and uncertainties for a physically motivated model for broad absorption line outflows. This tool makes robust analysis of famously complicated FeLoBAL quasars possible. In order to discover more FeLoBAL quasars for SimBAL analysis, I trained a Convolutional Neural Net on a sample of synthetic FeLoBAL quasar spectra, and used the model to identify real FeLoBAL quasars in the Sloan Digital Sky Survey. This model nearly tripled the number of known FeLoBALs (paper in prep).

I'm interested in using machine learning techniques to better understand large observational surveys (like Sloan or the upcoming Vera Rubin Observatory).

Here is a link to my undergraduate research post on Astrobites!

Here is a link to some lessons I've made on topics I find interesting.

Below is a video of a Mandelbrot zoom that I made with this python script.