NOAO >   Observing Info >   Approved Programs >   2009A-0118

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Proposal Information for 2009A-0118


PI: Dennis Zaritsky, University of Arizona, dzaritsky@as.arizona.edu
Address: Astronomy Department, 933 N. Cherry Ave., Tucson, AZ 85721, USA

CoI: Daniel Christlein, MPA

Title: The Mysterious Case of MCG -01-31-002

Abstract: MCG-01-31-002 has a uniform, ionized gas component that extends beyond two optical disk radii (> 2R_25), with a velocity dispersion of ~ 100 km s^-1, and rotates with the disk of the galaxy. The size and velocity dispersion of this component is unprecedented. However, our discovery observation was only along the disk's major axis toward one side of the galaxy. Therefore, we do not know the spatial extent and symmetry of this component, making it difficult to understand its origin. Such a component should not be stable (pressure supported gas, analogous to the hot halos of clusters or elliptical galaxies, would be much hotter), and so naively this suggests either massive outflow or inflow. However, the galaxy is undisturbed, isolated, and otherwise unremarkable - and the kinematics of the ionized gas observed so far do not suggest outflow or inflow. Therefore, this may be a previously unknown galactic component that happens to be relatively brighter in this galaxy than in the ~ 20 other galaxies where we found no such component. We propose a program to examine further this unusual galaxy.


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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