NOAO > Observing Info > Approved Programs > 2012B-0102
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NOAO > Observing Info > Approved Programs > 2012B-0102 |
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PI: Mischa Schirmer, Gemini Observatory, mschirme@gemini.edu
Address: Southern Operations Centre, Casilla 603, La Serena, Chile
CoI: Sherry Suyu, University of California
CoI: Rodrigo Carrasco, Gemini Observatory
CoI: Karianne Holhjem, SOAR telescope
Title: Determining the redshift of the strong lens system in the fossil group J0454-0309
Abstract:
Fossil groups of galaxies exhibit very bright elliptical galaxies,
embedded in a diffuse X-ray halo, and form potential seeds for the
brightest cluster galaxies (BCGs). These groups are thought to
represent the last stage of mass assembly in the Universe. Only a few
dozen fossil systems are known to date, and only one of them, J0454-
0309, features a strongly lensed gravitational arc. We have argued in
Schirmer et al. (2010) that the lensing geometry of this system implies
that its giant elliptical does not lie at the center of the group's
gravitational potential. This contradicts current theories of structure
formation. The only possible explanation is an infall scenario, where
the elliptical formed outside and is now infalling into a sparse
cluster, or that galaxies in a filament stream along the line of sight
onto the fossil group. To confirm that the offset is indeed real (and
thus the infall scenario), we must confirm the nature of the lensed
counter image and prove the arc to be at high redshift.
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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NOAO > Observing Info > Approved Programs > 2012B-0102 |
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