EDP Sciences
Free access
Issue
A&A
Volume 405, Number 2, July II 2003
Page(s) L19 - L22
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20030760


A&A 405, L19-L22 (2003)
DOI: 10.1051/0004-6361:20030760

Letter

Discovery of a z = 6.17 galaxy from CFHT and VLT observations

J.-G. Cuby1, O. Le Fèvre2, H. McCracken3, J.-C. Cuillandre4, E. Magnier4 and B. Meneux2

1  European Southern Observatory, Paranal, Casilla 19001, Santiago 19, Chile
2  Laboratoire d'Astrophysique de Marseille, France
3  Osservatorio Astronomico di Bologna, Italy
4  Canada-France-Hawaii Telescope Corporation, Hawaii, USA

(Received 1 April 2003 / Accepted 19 May 2003)

Abstract
We report the discovery of a galaxy at a redshift  z = 6.17 identified from deep narrow band imaging and spectroscopic follow-up in one of the CFHT-VIRMOS deep survey fields at 0226-04. In addition to the existing deep BVRI  images of this field, we obtained a very deep narrow band image at 920 nm with the aim of detecting Ly $\alpha$ emission at redshift ~6.5. Spectroscopic follow-up of some of the candidates selected on the basis of their excess flux in the NB920 filter was performed at the VLT-UT4 with the FORS2 instrument. For one object a strong and asymmetric emission line associated with a strong break in continuum emission is identified as Ly $\alpha$ at z = 6.17. This galaxy was selected from its continuum emission in the 920 nm filter and not from its Ly $\alpha$ emission, in effect performing a Lyman Break detection at  z = 6.17. We estimate a star formation rate of several tens of  $M_\odot$ yr -1 for this object, with a velocity dispersion ~400 km s -1. The spectroscopic follow-up of other high z galaxy candidates is on-going.


Key words: galaxies: high-redshift -- early Universe -- techniques: spectroscopic

Offprint request: J.-G. Cuby, jcuby@eso.org

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