Jeong, Donghui and Schmidt, Fabian and Hirata, Christopher M. (2012) Large-scale clustering of galaxies in general relativity. Physical Review D, 85 (2). 023504. ISSN 0556-2821. http://resolver.caltech.edu/CaltechAUTHORS:20120206-151838806
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Several recent studies have shown how to properly calculate the observed clustering of galaxies in a relativistic context, and uncovered corrections to the Newtonian calculation that become significant on scales near the horizon. Here, we retrace these calculations and show that, on scales approaching the horizon, the observed galaxy power spectrum depends strongly on which gauge is assumed to relate the intrinsic fluctuations in galaxy density to matter perturbations through a linear bias relation. Starting from simple physical assumptions, we derive a gauge-invariant expression relating galaxy density perturbations to matter density perturbations on large scales, and show that it reduces to a linear bias relation in a synchronous-comoving gauge, corroborating an assumption made in several recent papers. We evaluate the resulting observed galaxy power spectrum, and show that it leads to corrections similar to an effective non-Gaussian bias corresponding to a local f_(NL,eff)≲0.5. This number can serve as a guideline as to which surveys need to take into account relativistic effects. We also discuss the scale-dependent bias induced by primordial non-Gaussianity in the relativistic context, which again is simplest in a synchronous-comoving gauge.
|Additional Information:||© 2012 American Physical Society. Received 19 August 2011; published 4 January 2012. We would like to thank Olivier Doré and the participants of the Michigan non-Gaussianity workshop for helpful discussions. D. J. and F. S. are supported by the Gordon and Betty Moore Foundation at Caltech. C. H. is supported by the U.S. National Science Foundation (AST-0807337), the U.S. Department of Energy (DE-FG03-02-ER40701), and the David and Lucile Packard Foundation.|
|Classification Code:||PACS: 98.65.Dx, 98.80.Jk|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Jason Perez|
|Deposited On:||07 Feb 2012 00:03|
|Last Modified:||26 Dec 2012 14:48|
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