NOAO >   Observing Info >   Approved Programs >   2013B-0325

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Proposal Information for 2013B-0325


PI: Kathy Vivas, Centro de Investigaciones de Astronomia (CIDA), akvivas@cida.ve
Address: Ave. Alberto Carnevali, Sector La Hechicera, Merida, Merida 5101-A, Venezuela

CoI: Mario Mateo, University of Michigan
CoI: David Nidever, University of Michigan

Title: Dwarf Cepheids in the Sagittarius dSph Galaxy

Abstract: Pulsating stars below the horizontal branch (aka, dwarf cepheids) provide an interesting tool to study the stellar populations and structure of dSph galaxies. They obey a period-luminosity relationship and allow determination of distances with precisions as good as RR Lyrae stars (5-7%). They also trace a range of stellar populations since stars coming from different evolutionary paths may coexist in the region of the instability strip. We propose to use the large field of view of DECam to survey for the first time the Sagittarius galaxy for dwarf cepheids. We expect to discover several hundreds of dwarf cepheids which would allow us to investigate trends along the core region with good statistics. We will use the dwarf cepheids to study the stellar population(s) that produce them as well as any population gradient, if it exists, along the galaxy core. In addition, the large number of stars will allow us to study the 3D structure of the Sgr core which is an important constraint in any model of the disruption of Sgr. RR Lyrae and anomalous cepheids will naturally appear as well in the data, adding additional constraints in our study.


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