Nial Tanvir, James Rhoads, Sangeeta Malhotra, Malcolm Bremer, Elizabeth Stanway, Klaas Wiersema, Johan Fynbo, Pall Jakobsson, Andrew Fruchter, Jens Hjorth, Karl Svensson
Abstract
Finding and studying sources in the era of reionization is the dominant driving force behind many projects in contemporary astrophysics. Our discovery of GRB090423 at z=8.2 offers a new window on the galaxy population only 600Myrs after the Big Bang. By good fortune, our redshift measurement places Lyman-alpha in a dark region of the spectrum between bright sky lines. We therefore propose a deep search for Lyman-alpha emission from the host and any neighbouring galaxies, making use of an existing NIRI narrow-band filter. These observations will give crucial new constraints on clustering, star-formation and emergent UV flux for galaxies at these early times, and they form a key part of our intensive multiwavelength study of the GRB090423 field.