NGC 3200, SINGG Survey

Gas-rich galaxies display a wide range of structures and properties, but one thing they all seem to have are some newly formed stars. Images from the Survey for Ionization in Neutral Gas Galaxies (SINGG), an NOAO Survey Program (obtained with the CTIO 1.5m telescope), are designed to highlight areas of star formation in gas rich galaxies. This spiral galaxy is tilted away from our line of sight and has one of the highest neutral hydrogen (HI) contents of the single galaxies in the SINGG study - nearly 40 billion (4 x 1010) times the mass of the sun. Other sources with this much HI turn out to be multiple galaxies. The image is displayed so that stars have a cyan-blue appearance, while ionized hydrogen (H-alpha) emission appears orange-red to yellow. The H-alpha emission marks where the gas in the galaxies has been stripped of electrons, and is now recombining. It takes very hot O stars to ionize the gas; these stars have very short lifetimes (a few million years). As a result, red tones in these images typically mark the location of newly formed hot stars. Gerhardt Meurer of The Johns Hopkins University, Baltimore, MD, is the principal investigator for SINGG. For more information, see: http://sungg.pha.jhu.edu/