Letter to the Editor

The Wide Field Imager Lyman-Alpha Search (WFILAS) for galaxies at redshift ~5.7 ^*,**

I. A spatially compact Lyα  emitting galaxy at redshift 5.721

¹ Research School of Astronomy & Astrophysics, The Australian National University, Weston Creek ACT 2611, Australia e-mail: [westra;heath]@mso.anu.edu.au
² European Southern Observatory, Casilla 19001, Santiago 19, Chile e-mail: [clidman;tszeifer;epompei;lvanzi]@eso.org
³ National Centre for Radio Astrophysics, Tata Institute of Fundamental Research Pune University Campus, Post Bag 3, Ganeshkhind Pune 411007, India e-mail: rathreya@ncra.tifr.res.in
⁴ Max Planck Institute für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany e-mail: meise@mpia.de
⁵ Department of Astrophysics, Denys Wilkinson Building, University of Oxford, Keble Road, Oxford, OX1 3RH, UK e-mail: cwolf@astro.ox.ac.uk

Received: 1 October 2004
Accepted: 26 November 2004

Abstract

We report the spectroscopic confirmation of a compact Lyα   emitting galaxy at . A FORS2 spectrum of the source shows a strong asymmetric line with a flux of erg s^-1 cm^-2, making it one of the brightest Lyα   emitting galaxies at this redshift, and a line-of-sight velocity dispersion of 400 km s^-1. We also have a tentative detection of a second, narrower component that is redshifted by 400 km s^-1 with respect to the main peak. A FORS2 image shows that the source is compact, with a FWHM of 05, which corresponds to 3.2 kpc at this redshift. This source is a brighter example of J1236.8+6215 ([CITE], ApJ, 570, 92), another Lyα  emit ting galaxy at .