NOAO >   Observing Info >   Approved Programs >   2016A-0196

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Program Information for 2016A-0196


PI: Kathy Vivas, CTIO, kvivas@ctio.noao.edu
Address: Casilla 603, La Serena Chile

CoI: Alistair Walker, CTIO
CoI: David James, CTIO
CoI: Eduardo Balbinot, University of Surrey
CoI: Jennifer Marshall, Texas A&M U.
CoI: Alex Drlica-Wagner, FNAL
CoI: Basilio Santiago, UFRGS
CoI: Joshua Simon, Carnegie Observatories

Title: Improving the Distance Determination to the New Dwarf Galaxies around the Milky Way

Abstract: We propose to obtain time series images of four Milky Way dwarf satellites recently discovered with the Dark Energy Camera (DECam). We will use the SOI instrument on the SOAR telescope to search in an efficient manner for variable stars in these dwarf galaxies. The observations will be used to locate RR Lyrae variables and to measure their periods, which will be used to produce an improved distance determination to the galaxies. An accurate distance measurement is crucial when characterizing these low luminosity systems since important parameters, such as the physical half-light radius and the absolute magnitude, depend primarily on the distance to the object. RR Lyrae stars have been discovered in all dwarf galaxies in which appropriate searches for variables have been conducted, including systems with absolute magnitudes as low as $M_V = -1.5$ (Segue 1). In addition, we will search for other types of variable stars, e.g. anomalous cepheids, whose presence (or lack thereof of) will provide an alternative method to study the stellar populations of the dwarf galaxies.

Program Type: Standard/Galactic

Scheduled Nights:
Run 1 (2016A):  SOAR/SOI -- 4n on Jun 21 2016, Jul 15 - Jul 16 2016, Jul 23 2016


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 >   2016A-0196

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