Astronomy Colloquium - "UGC2885 "Rubin's Galaxy"; a Gentle Giant Spiral Galaxy"
(sign-up)Dr. Benne Holwerda, University of Louisville
|Event Contact:||Rebecca Bare
|Sponsor:||Department of Astronomy|
UGC 2885 was discovered to be the most extended disk galaxy [250 kpc diameter] by Vera Rubin in the 1980's. It is close enough for HST observations to resolve the globular cluster population. This galaxy is a substantially more extended and massive disk than any whose cluster population has been studied before. Cold dark matter galaxy assembly implies that the globular cluster population comes from smaller accreted systems and the disk — and the clusters associated with it — predominantly from gas accretion, matching angular momentum to the disk's. Several scaling relations between the globular cluster population and parent galaxy have been observed but these differ for disk and spheroidal (more massive) galaxies. This galaxy is an ideal test case of these scaling relations as it lies between spiral and massive ellipticals. I present our first results on the globular cluster population of this massive disk galaxy, which we propose to rename "Rubin's Galaxy".
The center of Rubin’s Galaxy offers another interesting test case for an active galactic nucleus in a massive disk-dominated and isolated galaxy. Based on the Sloan Digital Sky Survey, Wu & Peek predict spectra for galaxies using images from PAN-STARRS as input.
The predicted spectrum for Rubin’s galaxy using this machine learning approach showed moderate AGN activity. Subsequently retrieved archival spectra and MMT observations show excellent agreement with the ML prediction.
Topic: Astronomy Colloquium (SP2021)
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