Martin, Crystal L. and Scannapieco, Evan and Ellison, Sara L. and Hennawi, Joseph F. and Djorgovski, S. G. and Fournier, Amanda P. (2010) The Size and Origin of Metal-enriched Regions in the Intergalactic Medium from Spectra of Binary Quasars. Astrophysical Journal, 721 (1). pp. 174-192. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:20101027-091529164
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We present tomography of the circum-galactic metal distribution at redshift 1.7-4.5 derived from echellete spectroscopy of binary quasars. We find C IV systems at similar redshifts in paired sightlines more often than expected for sightline-independent redshifts. As the separation of the sightlines increases from 36 kpc to 907 kpc, the amplitude of this clustering decreases. At the largest separations, the C IV systems cluster similar to the Lyman-break galaxies studied by Adelberger et al. in 2005. The C IV systems are significantly less correlated than these galaxies, however, at separations less than R_1 0.42 ± 0.15 h^( –1) comoving Mpc. Measured in real space, i.e., transverse to the sightlines, this length scale is significantly smaller than the break scale estimated previously from the line-of-sight correlation function in redshift space by Scannapieco et al. in 2006. Using a simple model, we interpret the new real-space measurement as an indication of the typical physical size of enriched regions. We adopt this size for enriched regions and fit the redshift-space distortion in the line-of-sight correlation function. The fitted velocity kick is consistent with the peculiar velocity of galaxies as determined by the underlying mass distribution and places an upper limit on the average outflow (or inflow) speed of metals. The implied timescale for dispersing metals is larger than the typical stellar ages of Lyman-break galaxies, and we argue that enrichment by galaxies at z > 4.3 played a greater role in dispersing metals. To further constrain the growth of enriched regions, we discuss empirical constraints on the evolution of the C IV correlation function with cosmic time. This study demonstrates the potential of tomography for measuring the metal enrichment history of the circum-galactic medium.
|Additional Information:||© 2010 The American Astronomical Society. Received 2010 June 3; accepted 2010 July 18; published 2010 August 26. We thank Nicolas Bouché, Jon Oiler, and Rob Thacker for discussions that improved the content of this paper. C.L.M. acknowledges support for this work from the David and Lucile Packard Foundation and NSF grant AST-080816. E.S. acknowledges support from NASA theory grant NNX09AD10G. S.G.D. acknowledges partial support from NSF grants AST-0407448 and AST-0909182, and the Ajax Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. We thank Mr. Kurt Soto, Dr. Grant Hill, and Dr. Greg Wirth for assistance during the observing runs. Facilities: Keck:II|
|Subject Keywords:||cosmology: miscellaneous; galaxies: abundances; galaxies: halos; galaxies: high-redshift; intergalactic medium; quasars: absorption lines|
|Classification Code:||PACS: 98.54.Aj; 95.30.Ky; 98.62.Nx; 98.62.Py; 98.62.Ra|
|Official Citation:||Crystal L. Martin et al 2010 ApJ 721 174. doi: 10.1088/0004-637X/721/1/174|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||12 Nov 2010 00:24|
|Last Modified:||26 Dec 2012 12:33|
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