Astron. Astrophys. 343, L19-L24 (1999)

Letter to the Editor

The VLT observations of the HDF-S NICMOS field: photometric catalog and high redshift galaxy candidates

A. Fontana ¹, S. D'Odorico ², R. Fosbury ³, E. Giallongo ¹, R. Hook ³, F. Poli ¹, A. Renzini ², P. Rosati ² and R. Viezzer <sup>2

1</sup> Osservatorio Astronomico di Roma, via dell'Osservatorio, I-00040 Monteporzio, Italy
² European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching, Germany
³ Space Telescope - European Coordinating Facility, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei München, Germany

Received 1 December 1998 / Accepted 12 January 1999

Abstract

We present the deep UBVRI observations of the HDF-S NICMOS field obtained as part of the Science Verification of the VLT Unit 1 telescope. The images have been used to construct object catalogs and to obtain photometric redshifts. The effective field of view is arcsec², and the formal limiting magnitudes (in a 2 FWHM aperture) are 26.3, 27.8, 27.5, 26.9, 25.2 in the U, B, V, R and I bands, respectively. Thanks to the sub-arcsecond image quality, relatively long exposure time, and large collecting area of the VLT, this is the deepest set of multicolor images ever obtained from a ground-based telescope.

Galaxy counts have been derived independently in each band, and show no significant departures from previous data from wider areas. A multicolor photometric catalog of all the galaxies selected in the R band has also been obtained and used to derive photometric redshifts for all galaxies with , using also the J,H and K magnitudes from the NICMOS deep observations. A significant fraction (28%)of the galaxies is placed at . Among them, six robust candidates are found at .

Key words: galaxies: general cosmology: observations

Send offprint requests to: A. Fontana (fontana@quasar.mporzio.astro.it)

SIMBAD Objects

Contents

• 1. Introduction
• 2. The data sample
  • 2.1. Observations and data reduction
  • 2.2. Photometric calibration
• 3. The photometric catalog
  • 3.1. Galaxy counts
  • 3.2. The multicolor catalog
• 4. The photometric redshifts of the galaxies
• Acknowledgements
• References

© European Southern Observatory (ESO) 1999

Online publication: March 1, 1999
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