NOAO >   Observing Info >   Approved Programs >   2015A-0416

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Program Information for 2015A-0416


PI: Katherine L Rhode, Indiana U., krhode@indiana.edu
Address: Department of Astronomy, 727 E. Third Street, Bloomington, IN 47405 USA

CoI: Katie Butler, Agnes Scott College
CoI: Michael Gregg, UC Davis
CoI: Michael West, Maria Mitchell Observatory

Title: A WIYN/Hydra Census of Ultra-Compact Dwarf Galaxy Candidates Selected from the SDSS

Abstract: Ultracompact dwarf galaxies (UCDs) are an intriguing new class of stellar systems that have masses of $\sim$10$^8$ solar masses and sizes only tens of parsecs across, making them some of the densest stellar systems known. About 100 UCDs have been discovered to date. To increase this modest number, and to look for UCDs in previously unexplored environments, we have identified candidates in the SDSS DR10 based on optimized color selection criteria. A few of these candidates have serendipitous velocity measurements in Sloan that suggest that they are bona fide UCDs, but the vast majority do not have measured velocities. Here we request time with WIYN/Hydra to obtain spectra for our color-selected sample of UCD candidates. The requested observations will allow us to reliably determine whether the objects are indeed newly- discovered UCDs and to further refine our UCD selection process. In addition to velocity measurements, line indices measured from the Hydra spectra can yield age and abundance estimates for the UCDs we identify. We note that while many of our targets are possible members of Virgo and its environs, some of the UCD candidates are in other regions, offering the possibility of discovering the first UCDs in low-density environments.

Program Type: ITAC

Scheduled Nights:
Run 1 (2015A):  WIYN/HYDR -- 5n on May 14 - May 18 2015


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2015A-0416

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