Astrophysical Sciences and Technology Colloquium: Exploiting Galaxy Kinematics with DESI

Astrophysical Sciences and Technology Colloquium
Exploiting Galaxy Kinematics with DESI

Dr. Kelly Douglass
University of Rochester

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Abstract:
The Hubble expansion of the universe dominates the recessional velocities of galaxies that we observe. However, galaxies move relative to each other on top of this expansion, adding their peculiar motion to the velocities that we measure. Disentangling these peculiar velocities from the Hubble expansion requires measuring the distances to galaxies independent of their redshifts. I will describe the DESI Peculiar Velocity Survey, a secondary targeting program within the Dark Energy Spectroscopic Instrument (DESI) Survey designed to measure the peculiar motion of more than 175,000 galaxies in the local universe. The largest peculiar velocity survey to date, this sample will have a significant impact on galaxy physics and cosmology, including reducing constraints on the growth rate of structure in the universe. I will share how we use spectroscopic observations from DESI to measure the rotational velocity of spiral galaxies and the velocity dispersion of elliptical galaxies, and how we calibrate the Tully-Fisher relation and the Fundamental Plane to convert these velocities into distances.

Speaker Bio:
Prof. Kelly Douglass is an Assistant Professor of Instruction in the Department of Physics & Astronomy at the University of Rochester, where she has worked since 2017. She became the Director of the C.E.K. Mees Observatory in 2021, she started helping run the Physics and Astronomy REU program at UR in 2022, and she took over as Director of Undergraduate Studies in Physics this past year. Originally from Doylestown, PA, Kelly earned her Bachelor's degree in Physics from Cornell University in 2011, and her Ph.D. in Physics from Drexel University in 2017. Kelly's research spans both extragalactic astrophysics and cosmology through using large galaxy redshift surveys like the Sloan Digital Sky Survey (SDSS) and the Dark Energy Spectroscopic Instrument (DESI). She spearheaded the development of VAST, the Void Analysis Software Toolkit, curating various voidfinding algorithms used to locate the most underdense regions of the universe. Kelly also helped design and leads the DESI Peculiar Velocity Survey, a secondary targeting program in DESI designed to use galaxy kinematics to measure the peculiar motion of galaxies in the local universe. With galaxy kinematics and voids, Kelly hopes to advance our understanding of galaxy formation and evolution.

Intended Audience:
Those with interest in the topic. Open to RIT and UofR Physics and Astronomy communities.

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