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arXiv · astro-ph/0302113

Constraints to the evolution of Ly-Alpha bright galaxies between z=3 and z=6

C. Maier·K. Meisenheimer·E. Thommes·H. Hippelein·H. J. Roeser·J. Fried·B. von Kuhlmann·S. Phleps·C. Wolf
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Abstract

Galaxies at high redshift with a strong Ly-Alpha emission line trace massive star formation in the absence of dust, and can therefore be regarded as a prime signature of the first major starburst in galaxies. We report results of the Ly-Alpha search within the Calar Alto Deep Imaging Survey (CADIS). With imaging Fabry-Perot interferometer CADIS can detect emission lines in three waveband windows free of night-sky emission lines at 700nm, 820nm, and 920nm. The typical flux detection limit for Ly-Alpha emission redshifted into these windows, Flim > 3X10^(-20) Wm^(-2), corresponds to (unobscured) star formation rates of >10Msun/yr at z=6. Candidate Ly-Alpha-emitting galaxies are selected from the total emission line sample, which contains more than 97% of objects at z<1.2, by the absence of flux below the Lyman limit (B-band "dropouts"), and the non-detection of secondary emission lines in narrow band filters. We have detected 5 bright Ly-Alpha-emitting galaxy candidates at z ~ 4.8, and 11 candidates at z ~ 5.7. For two of four observed Ly-Alpha candidates, one candidate at z ~ 4.8, and the other at z ~ 5.7, the emission line detected with the Fabry-Perot has been verified spectroscopically at the VLT. When compared to Ly-Alpha surveys at z<3.5 even the upper limits set by our list of candidates show that bright Ly-Alpha galaxies are significantly rarer at z>5 than the assumption of a non-evolving population would predict. Therefore we conclude that the Ly-Alpha bright phase of primeval star formation episodes reached its peak at redshifts between 3 and 6.

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C. Maier, K. Meisenheimer, E. Thommes, H. Hippelein, H. J. Roeser, J. Fried, B. von Kuhlmann, S. Phleps, C. Wolf. 2003-02-06. Constraints to the evolution of Ly-Alpha bright galaxies between z=3 and z=6. https://doi.org/10.1051/0004-6361%3A20030265

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