Will Cerny Honors Thesis Presentation

2:00–2:30 pm ERC 576

Will Cerny "A Guided Search for Ultra-Faint Dwarf Galaxy Satellites of the Milky Way Along RR Lyrae Sightlines"
Supervisor: Prof. Alex Drlica-Wagner

Abstract: Ultra-faint dwarf galaxies (UFDs) represent some of the least luminous, most dark-matter-dominated, and most metal-poor systems in the universe. Follow-up studies of UFDs orbiting the Milky Way have revealed that these systems nearly always host one or more RR-Lyrae-type variable stars (RRLs), leading several past studies to investigate whether these distinctive stars can be used to discover UFDs. Here, we present the most extensive "guided" search for UFDs in this vein to date, spanning >17,000 individual RRL sightlines covered by the second data release of the DECam Local Volume Exploration survey. We successfully recover all but one UFD system that we expect our search to be sensitive to, significantly surpassing the sensitivity of two existing RRL-based searches in the literature. Ultimately, however, we discover no previously unreported UFDs. We interpret this null result in the context of recent forward models of the Milky Way satellite galaxy population, and find that our non-detection of new systems can be partially - but not entirely - explained by incompleteness in current RRL catalogs. With the imminent public release of improved all-sky RRL catalogs from the third data release of the Gaia satellite, we predict that the methods presented here may enable the discovery of > 9 UFDs within 100 kpc (at 95% confidence).

Event Type

Seminars, Talks

May 26