NOAO >   Observing Info >   Approved Programs >   2012B-0285

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Proposal Information for 2012B-0285


PI: Christopher Haines, University of Arizona, cphaines@as.arizona.edu
Address: Steward Observatory, 933 North Cherry Avenue, Tucson, AZ 85721, USA

CoI: Ewan O'Sullivan, University of Birmingham, UK
CoI: Somak Raychaudhury, University of Birmingham, UK
CoI: Eiichi Egami, Steward Observatory
CoI: Luis Campusano, Universidad de Chile, Chile

Title: KPNO 0.9m H(alpha) Imaging Survey of ``Transforming Galaxies'' in Local Galaxy Groups

Abstract: We propose to use the KPNO 0.9-m telescope to obtain panoramic H(alpha) imaging of ~135 galaxies in ten nearby galaxy groups (60- 80 Mpc) from the Complete Local-Volume Groups Sample (CLoGS). In rich clusters ram-pressure stripping has been shown to be very effective at removing the gas contents and quenching star formation in infalling spiral galaxies. It is much less clear how galaxies are affected by the much lower ram pressures found in galaxy groups, or if other environmental processes begin to dominate. Given that >50% of galaxies in the local volume reside in groups, it is vital that we gain new insights into which mechanisms drive the SFR-density relation in groups. The proposed H(alpha) imaging will allow us to resolve \em where star-formation is occurring in each galaxy. This can effectively discriminate between ram-pressure stripping characterized by truncated H(alpha) disks, the much gentler starvation mechanism which produces anemic spirals, and nuclear starbursts triggered by low-velocity encounters and mergers which should be most frequent in groups.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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