Astron. Astrophys. 362, 509-518 (2000)

A large-area near-infrared emission line survey for star forming galaxies at z = 2.1-2.4 ^*

P.P. van der Werf ¹, A.F.M. Moorwood ² and M.N. Bremer <sup>1,3

1</sup> Leiden Observatory, P.O. Box 9513, 2300 RA Leiden, The Netherlands
² European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany
³ Institut d'Astrophysique de Paris, 98bis Blvd. Arago, 75014 Paris, France

Received 20 January 2000 / Accepted 4 August 2000

Abstract

We present a large-area survey for emission at redshifts from 2.1 to 2.4, using a combination of deep narrow-band and broad-band imaging in the near-infrared K-band. Our survey covers half the comoving volume of the widest available survey to date, but goes considerably deeper. We target volumes containing known damped systems and radio galaxies as well as random fields. We detect (in addition to the two radio galaxies and one known active galaxy) four emission objects, with implied star formation rates of 44 to for and no extinction correction. It is argued that these objects are most likely star forming galaxies at . The density of such sources in fields targeted at absorption line systems is found to be much higher than that in the vicinity of radio galaxies or quasars or in the general field at these redshifts. We discuss the properties of our detected sources and target fields, and suggest how future surveys of this type can be used to derive the cosmic star formation history.

Key words: galaxies: evolution galaxies: starburst

* Based on observations collected at the European Southern Observatory, Chile.

Present address: University of Bristol, Department of Physics, Tyndall Avenue, Bristol, BS8 1TL, England

Send offprint requests to: P. van der Werf
(pvdwerf@strw.leidenuniv.nl)

© European Southern Observatory (ESO) 2000

Online publication: October 24, 2000

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