NOAO >   Observing Info >   Approved Programs >   2003A-0066

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Proposal Information for 2003A-0066


PI: Sylvain Veilleux, University of Maryland, veilleux@astro.umd.edu
Address: Department of Astronomy, College Park, MD 20742, USA

CoI: David S. Rupke, University of Maryland

Title: Superwinds in Ultraluminous Infrared Galaxies: The Spring Sample

Abstract: Large-scale galactic outflows, or superwinds, are ubiquitous in both local and high-z (Lyman-break) star-forming galaxies. They likely have a substantial impact on galaxy formation and evolution, and are responsible for at least some of the observed heating and enrichment of the intergalactic and intracluster media. Yet the nature and frequency of superwinds over most of cosmic history remains unquantified. We are conducting a survey of starburst-dominated ultraluminous infrared galaxies (ULIGs) in the range 0.1 < z < 0.6. We have confirmed outflows of warm neutral gas in 8 low-z (z < 0.3) and 7 moderate-z (z > 0.3) ULIGs. Blueshifted absorption in the \ionNa1 D feature indicates the presence of superwinds, and our initial analysis shows that the reheating efficiency and gaseous escape fraction in these winds are high. This suggests that ULIGs are significant polluters of the intergalactic medium at moderate z, given that their number density increases strongly with z, contrary to model predictions that only low- mass galaxies pollute the IGM. To better quantify the average characteristics of outflows in massive galaxies and their impact on the IGM, we must double our sample size at both low and moderate z. We propose to use the R-C spectrograph on the KPNO 4m for z < 0.3 objects and the Red Channel spectrograph (in echellette mode) on the MMT for z > 0.3 to accomplish this. Our previous data were obtained on Keck II in the context of another program; we do not have further guaranteed or direct access to this telescope. The first two KPNO 4m runs to enlarge the low-z sample were lost to bad weather (Oct 2001, July 2002). This survey is part of an approved Ph.D. thesis project (D. Rupke).


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