# Cosmic reionisation

1. Aug 7, 2005

### wolram

http://arxiv.org/abs/astro-ph/0508123

Title: Searching for the Sources Responsible for Cosmic Reionization: Probing 7 < z < 10 and Beyond
Authors: Daniel P. Stark, Richard S. Ellis (Caltech)
Comments: 12 pages, 6 figures, to appear in "First Light & Reionization", eds. E. Barton & A. Cooray, New Astronomy Reviews, in press

(Abridged) We review recent observations that suggest the star formation rate density is declining over 3$<z<$7 and illustrate the challenges that this poses in explaining the assembled stellar mass in z$\sim$6 galaxies deduced from Spitzer data. A plausible conclusion is a vigorous period of earlier star formation. Prior to JWST and TMT, strong lensing offers a unique probe of the extent of this earlier activity. We discuss the first results of a blind spectroscopic survey of lensing clusters for 8.5$<z<$10 Ly$\alpha$ emitters using NIRSPEC which is achieving a limiting star formation rate of 0.1 $M_{\odot}$ yr$^{-1}$. A companion HST/IRAC survey is targeting lensed $z$ and $J$-band dropouts and probes a $\simeq$1 arcmin$^2$ region 1 magnitude deeper than the UDF/NICMOS observations. Both surveys will constrain the contribution of early, low luminosity, sources to cosmic reionization.