DOI: 10.1051/0004-6361/200912626
Deep U-B-V imaging of the Lockman Hole with the LBT
Observations and number counts
E. Rovilos1, V. Burwitz1, G. Szokoly1, 2, G. Hasinger3, E. Egami4, N. Bouché1, S. Berta1, M. Salvato3, 5, D. Lutz1, and R. Genzel11 Max Planck Institut für extraterrestrische Physik, Giessenbachstraße, 85748 Garching, Germany
e-mail: erovilos@mpe.mpg.de
2 Institute of Physics, Eötvös University, Pázmány P. s. 1/A, 1117 Budapest, Hungary
3 Max Planck Institut für Plasmaphysik, Boltzmannstraße 2, 85748, Garching, Germany
4 Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA
5 California Institute of Technology, MC 205-24, 1200 East California Boulevard, Pasadena, CA 91125, USA
Received 3 June 2009 / Accepted 25 August 2009
Abstract
We used the large binocular camera (LBC) mounted on the large binocular
telescope (LBT) to observe the Lockman Hole in the U, B, and V bands. Our
observations cover an area of 925 arcmin2. We reached depths of 26.7,
26.3, and 26.3 mag(AB) in the three bands, respectively, in terms of 50%
source detection efficiency, making this survey the deepest U-band survey
and one of the deepest B and V band surveys with respect to its covered area.
We extracted a large number of sources (~89 000), detected
in all three bands
and examined their surface density, comparing it with models of galaxy
evolution. We find good agreement with previous claims of a steep faint-end
slope of the luminosity functions, caused by late-type and irregular
galaxies at z>1.5. A population of dwarf star-forming galaxies at
1.5<z<2.5 is needed to explain the U-band number counts. We also find
evidence of strong supernova feedback at high redshift.
This survey is complementary to the r, i, and z Lockman Hole survey conducted
with the Subaru telescope and provides the essential wavelength coverage
to derive photometric redshifts and select different types of sources from
the Lockman Hole for further study.
Key words: surveys -- galaxies: photometry
© ESO 2009