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

Authors :: Cuby, J.-G.
Le Fèvre, O.
McCracken, H.
Cuillandre, J.-C.
Magnier, E.
Meneux, B.
Cuby, J.-G.
Le Fèvre, O.
McCracken, H.
Cuillandre, J.-C.
Magnier, E.
Meneux, B.
Source :: Astronomy and Astrophysics; July 2003, Vol. 405 Issue: 2 pL19-L22, 4p
Publication Year :: 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 BVRIimages of this field, we obtained a very deep narrow band image at 920 nm with the aim of detecting Lyαemission 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 Lyαat $z = 6.17$. This galaxy was selected from its continuum emission in the 920 nm filter and not from its Lyαemission, in effect performing a Lyman Break detection at $z = 6.17$. We estimate a star formation rate of several tens of $M_\odot$yr-1for this object, with a velocity dispersion ~400 km s-1. The spectroscopic follow-up of other high zgalaxy candidates is on-going.