In this letter we report on the discovery of a z=2.83 Lyman-alpha Blob (LAB) found in our wide field narrow-band survey within the Spitzer First Look Survey region. The blob is extended over at least 95kpc and has a total Lyman-alpha luminosity of 2.1 x 10^44 erg/s. It is only the sixth LAB known of this scale (> 50 kpc), and is associated with an embedded continuum source in g', R, i', K & 4.5 um bands. The LAB's optical spectrum shows clumpy structures and tantalising hints of a sharp red cut-off and shear within the Ly-alpha emission line. Studies of the LAB's surface brightness profile and of the continuum counterpart's spectral energy distribution (SED) indicate that the profuse Lyman-alpha emission is consistent with being powered by cold gas accreting onto a massive dark matter halo.
@article{arxiv.astro-ph/0703522,
title = {Evidence for Cold Accretion onto a Massive Galaxy at High Redshift?},
author = {Daniel J. B. Smith and Matt J. Jarvis},
journal= {arXiv preprint arXiv:astro-ph/0703522},
year = {2008}
}
Comments
6 pages, 4 figures, accepted by MNRAS. Replacement to match published version