NOAO >   Observing Info >   Approved Programs >   2012A-0427

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Proposal Information for 2012A-0427


PI: Chao-Wei Tsai, California Institute of Technology, cwtsai@ipac.caltech.edu
Address: Infrared Processing and Analysis Center, M/S 100-22, Pasadena, CA 91125, U.S.A.

CoI: Roger Griffith, IPAC, Caltech
CoI: Daniel Stern, JPL/Caltech
CoI: Thomas Jarrett, IPAC, Caltech
CoI: Peter Eisenhardt, JPL
CoI: Lin Yan, IPAC, Caltech
CoI: Spencer Stanford, UC Davis
CoI: Yanling Wu, Mars and Co
CoI: Sara Petty, UCLA
CoI: Dominic Benford, GSFC, NASA
CoI: Jingwen Wu, JPL
CoI: Frank Masci, IPAC, Caltech
CoI: Carrie Bridge, Caltech
CoI: Andrew Blain, U of Leicester

Title: Searching for Mid-IR Bright, Low-Metallicity Blue Compact Dwarf Galaxies

Abstract: We request 2 nights of SOAR Goodman spectrograph follow-up observations of a sample of southern mid-IR bright, blue compact dwarf galaxy (BCD) candidates at z < 0.1. This is a complementary project to our ongoing Palomar Double Spectrograph program in the northern sky via JPL. We will study the metallicity, extinction, and star formation rate of these objects from their high S/N ratio spectra of hydrogen and oxygen lines. These galaxies, selected using the IR data from Wide- Field Infrared Survey Explorer (WISE), have the same WISE colors with red ULIRGs and obscured AGNs between 3.4 and 12 micron, but significantly brighter at optical wavelengths. The preliminary search results suggest that about 40% - 50% of WISE objects selected with these color and brightness criteria are BCDs or their higher luminosity analogs. Keck and Palomar optical spectroscopic data reveal that the metallicities of a significant fraction of them are 1/10 of solar or lower. These low metallicity, mid-IR bright BCDs are a unique sample for studying the dust grain formation in the low metallicity environment, and help us to understand the thermal dust emission of high- redshift galaxies.


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 >   2012A-0427

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