GALAXY SURVEY
PRESENTATION The Cosmic Dawn Survey is a 50 square degree multi-wavelength survey of the Euclid Deep and Calibration fields. The scientific aim is to understand the co-evolution of galaxies, black holes, and the dark matter haloes that host them from Re-Ionization (z~12, about 500 million years after the big-bang) to the present (z~0). The current dataset comprises ultra-deep griz imaging as part of the H20 Survey and IRAC infrared imaging from the Spitzer Legacy Survey, and will eventually include near-infrared imaging from the Euclid Space Mission from 2022. I am a co-lead of the photometric extraction, redshift computation, and physical parameters team, using The Farmer to produce bleeding-edge measurements of galaxy properties.
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PUBLICATION IN PREPARATION
PhD Student @ The Cosmic Dawn Center, 2018-2020 PRESENTATION The COSMOS survey is one the longest-running galaxy surveys. Over two decades, we have collected observations of x-ray, optical, infrared, and radio light to obtain galaxy distances and understand their evolution over 13.7 billion years of cosmic history. I lead the 2020 edition of the master galaxy catalog, using bleeding-edge galaxy model-fitting techninques from The Farmer to measure galaxy properties. PUBLICATION IN PREPARATION
PhD Student @ The Cosmic Dawn Center, 2018-2020 ADS | PRESENTATION While the increasing depth and area of galaxy surveys promise definitive high-redshift studies, ever more crowded sources challenge current photometric methodology. Recent work by Lang and Hogg (2016) has provided another toolkit: The Tractor. By leveraging our understanding of galaxy morphologies, the Tractor is able to force galaxy models derived from high-resolution images onto less resolved ones, with superior deblending and robust photometric redshifts ─ advantageous for high-redshift studies. We present the Farmer, a comprehensive software interfacing with The Tractor to detect sources, efficiently determine the best model type for each source, and perform forced photometry in a scalable architecture. PRESENTED AT NAM 2016
Research Student @ University of St Andrews, 2015-2018 PAPER | PRESENTATION We present a study of 9258 quasars observed with multi-epoch ugriz photometry with spectroscopic redshifts as part of the SDSS Southern Survey. Using a linear model to fit the spectral variations, we isolate separate spectra for the variable (disc) non-variable(disc + galaxy) components of each quasar. We find evidence for bluer spectral slopes than predicted by cannonical accretion disc theory and excellent agreement with SMC-like dust extinction. This work provides the first direct evidence to support recent groundbreaking theoretical efforts to analytically describe accretion discs in the context of General Relativity and magnetic stress. PUBLISHED IN THE ASTROPHYSICAL JOURNAL
PhD Student @ Cosmic Dawn Center, 2019 ADS | PAPER Large photometric surveys provide a rich source of observations of quiescent galaxies, including a surprisingly large population at z > 1. However, identifying large, but clean, samples of quiescent galaxies has proven difficult because of their near-degeneracy with interlopers such as dusty, star-forming galaxies. We describe a new technique for selecting quiescent galaxies based upon t-distributed stochastic neighbor embedding which provides an improvement both over UVJ. It also may be able to select quiescent galaxies more efficiently at higher redshifts than the training sample. |
Research ProjectsA "completed" project is a matter of perspective. Archives
June 2020
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