NOAO >   Observing Info >   Approved Programs >   2013A-0253

Small NOAO Logo

Proposal Information for 2013A-0253


PI: Elizabeth Adams, Cornell University, betsey@astro.cornell.edu
Address: Astronomy Department, 518 Space Sciences Bldg, Ithaca, NY 14853, USA

CoI: John Cannon, Macalester College
CoI: Riccardo Giovanelli, Cornell University
CoI: Martha Haynes, Cornell University
CoI: Katherine Rhode, Indiana University
CoI: John Salzer, Indiana University

Title: Optical Imaging of Local Group Galaxy Candidates from the ALFALFA Survey

Abstract: Giovanelli \etal (2010) identified within the dataset of the ALFALFA HI survey a small set of ultra-compact high velocity clouds (UCHVCs). If placed at distances of ~1 Mpc, these clouds show the structural characteristics of the gas-bearing ``minihalos'' proposed by Sternberg et al. (2002) but could easily be too optically faint and distant to have been discovered by existing optical surveys. It was recently discovered (Giovanelli \etal 2012; Rhode \etal 2012) that a low velocity (cz ~ +260 km/s), narrow line width, compact HI cloud detected by the ALFALFA survey is, in fact, a very nearby (0.5 Mpc \textless D \textless 1.5 Mpc), optically faint but star-forming, low mass galaxy, termed Leo P. This validates the hypothesis that some of the ALFALFA UCHVCs may be such isolated, very low mass dark matter halos. Too faint and distant to have been detected in existing optical surveys, Leo P is the first ultrafaint dwarf galaxy discovered by its HI signature, and its existence strongly argues that other very low mass and (nearly) starless objects are included among the ALFALFA UCHVCs. This proposal requests deep optical observations of the very best ALFALFA candidate low mass galaxies to search for optical counterparts to constrain their distance and stellar populations.


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 >   2013A-0253

noaoprop-help@noao.edu

Small NOAO Logo