S. Camera, M. G. Santos, D. J. Bacon, M. J. Jarvis, K. McAlpine, R. P. Norris, A. Raccanelli, H. Rottgering
In this paper we explore the impact of including redshift information on cosmological applications with the forthcoming generation of large-scale, deep radio continuum surveys. By cross-matching these radio surveys with shallow optical to near-infrared surveys we can essentially separate the source distribution into a low redshift sample and the high-z tail of the radio sources that are unidentified, thus providing a constraint on the evolution of cosmological parameters such as those of dark energy. We examine two radio surveys, the Evolutionary Map of the Universe (EMU) and the Westerbork Observations of the Deep APERTIF Northern sky (WODAN). A crucial advantage is their combined potential to provide a deep, full-sky survey. The surveys used for the cross-identifications are SkyMapper and SDSS, for the southern and northern skies, respectively. We concentrate on the galaxy clustering angular power spectrum as our benchmark observable and find that the possibility of including this low redshift information yields major improvements in the results. With this approach, we are able to put strict constraints on the dark energy parameters, i.e. w_0=-0.9+/-0.065(0.087) and w_a=-0.24+/-0.19(0.26) with(without) priors from Planck; this corresponds to a Figure of Merit (FoM) of circa 400(>200), which is two to three orders of magnitude times better than the case without any redshift information and more than three times better than what obtained by using only the cross-identified sources.
View original:
http://arxiv.org/abs/1205.1048
No comments:
Post a Comment