NOAO >   Observing Info >   Approved Programs >   2004A-0369

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Proposal Information for 2004A-0369


PI: William Keel, University of Alabama, keel@bildad.astr.ua.edu
Address: Physics Department, Box 870324, Tuscaloosa, AL 35487-0324, USA

CoI: Frazer Owen, National Radio Astronomy Observatory
CoI: Michael Ledlow, Gemini Observatory
CoI: Daniel Wang, University of Massachussetts

Title: Signatures of stellar and gas stripping in the core of Abell 2125

Abstract: An extensive data set for the rich cluster Abell 2125 reveals several lines of evidence for recent and ongoing stripping of galaxies, involving both gas and stars, during a cluster-cluster merger. The velocity structure of this cluster allows an unusually clean set of spectroscopic tests for both the role of stripping and the details of how gas is now being stripped from one high-velocity galaxy, which already shows a history of starburst activity roughly coincident with its likely passage through the core ICM. A WIYN velocity field of the ~ 70-kpc [O II] plume from galaxy C153 will reveal whether it is indeed recently stripped gas interacting with the ICM, whose radial velocity differs by 2160 km/s. A GMOS long-slit measurement in the red will give localized information on line ratios (and ionized-gas mass) in this feature. GMOS IFU spectra covering the outer disk and minor axis will distinguish local star formation and shocks as ionization mechanisms, and trace the velocity field of presumably stripped gas as it leaves the galaxy. Finally, two GMOS spectra would yield the velocity and velocity dispersion of diffuse starlight in the cluster core, where the large radial-velocity spread of cluster constituents should allow us to tell where and when the stars left their parent galaxies. Existing data on stripping in clusters is sparse enough that this case alone can tell us much about how gas is driven out of galaxies in rich environments.


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NOAO >   Observing Info >   Approved Programs >   2004A-0369

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