NOAO >   Observing Info >   Approved Programs >   2001A-0191

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Proposal Information for 2001A-0191


PI: James Lowenthal, University of Massachusetts, james@astro.umass.edu
Address: LGRT 526, Amherst, MA 01060, USA

CoI: Matthew Bershady, University of Wisconsin
CoI: Rafael Guzman, Yale University
CoI: Jesus Gallego, Universidad Complutensia de Madrid

Title: Properties of Luminous Blue Compact Galaxies at z<1 and the Global Star Formation Rate Density

Abstract: Luminous blue compact galaxies (LBCGs) are important to understand because they are implicated as significant contributers both to the high global SFR density observed at z~1 and to the strong evolution of field galaxies between z=1 and the present. However, we do not yet have a good measure of their SFRs - both individual and global. Are LBCGs at redshifts z>0.4 the analogs of local \hii galaxies or even of Lyman break galaxies at z~3? What are their metallicity and dust extinction properties? Access to \ha, the best SFR measure, is problematic for intermediate redshift. Here we propose to address the above questions by obtaining near-IR spectra with FLAMINGOS of a well- selected sample of LBCGs to measure \ha fluxes directly. With fluxes in hand, we will: (1) measure SFRs using the most direct indicator available; (2) compare \ha to \oii SFRs to calibrate \oii estimators for other samples; (3) calculate the contribution of our sample to the global SFR density; (4) use \ha/\hb ratios to measure dust extinction; (5) combine EW(\ha) and K magnitudes to compute stellar masses; and (6) synthesize the above to investigate the putative link connecting \hii galaxies today, LBCGs at moderate redshift, and LBGs at z~3. Our sample is selected from our ongoing studies of compact star-forming galaxies in the HDF-N and three other fields with deep HST, Keck, and optical spectroscopic data in hand.


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