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Lyman-alpha emission galaxies at a redshift of z = 5.7 in the FORS Deep Field

C. Tapken·I. Appenzeller·A. Gabasch·J. Heidt·U. Hopp·R. Bender·D. Mehlert·S. Noll·S. Seitz·W. Seifert
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Abstract

We present the results of a search for Lyman-alpha emission galaxies at z~ 5.7 in the FORS Deep Field. The objective of this study is to improve the faint end of the luminosity function of high-redshift Lyman-alpha emitting galaxies and to derive properties of intrinsically faint Lyman-alpha emission galaxies in the young universe. Using FORS2 at the ESO VLT and a set of special interference filters, we identified candidates for high-redshift Lyman-alpha galaxies. We then used FORS2 in spectroscopic mode to verify the identifications and to study their spectral properties. The narrow-band photometry resulted in the detection of 15 likely Lyman-alpha emission galaxies. Spectra with an adequate exposure time could be obtained for eight galaxies. In all these cases the presence of Lyman-alpha emission at z = 5.7 was confirmed spectroscopically. The line fluxes of the 15 candidates range between 3 and 16 * 10^-21 Wm^-2, which corresponds to star-formation rates not corrected for dust between 1 and 5 Msun/yr. The luminosity function derived for our photometrically identified objects extends the published luminosity functions of intrinsically brighter Lyman-alpha galaxies. With this technique the study of high-redshift Lyman-alpha emission galaxies can be extended to low intrinsic luminosities.

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C. Tapken, I. Appenzeller, A. Gabasch, J. Heidt, U. Hopp, R. Bender, D. Mehlert, S. Noll, S. Seitz, W. Seifert. 2006-04-12. Lyman-alpha emission galaxies at a redshift of z = 5.7 in the FORS Deep Field. https://doi.org/10.1051/0004-6361%3A20064872

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