Volume 509, January 2010
|Number of page(s)||5|
|Published online||14 January 2010|
Letter to the Editor
The H-alpha luminosity function at redshift 2.2*
A new determination using VLT/HAWK-I
Geneva Observatory, University of Geneva, 51 chemin des Maillettes,
1290 Sauverny, Switzerland e-mail: firstname.lastname@example.org
2 Laboratoire d'Astrophysique de Toulouse-Tarbes, Université de Toulouse, CNRS, 14 Avenue E. Belin, 31400 Toulouse, France
3 Oskar Klein Center for Cosmoparticle physics, Department of Astronomy, Stockholm University, 10691 Stockholm, Sweden
Accepted: 7 December 2009
We aim to place new, strengthened constraints on the luminosity function (LF) of H-alpha (Hα) emitting galaxies at redshift , and to further constrain the instantaneous star-formation rate density of the universe (). We have used the new HAWK-I instrument at ESO-VLT to obtain extremely deep narrow-band (line; NB2090) and broad-band (continuum; ) imaging observations. The target field is in the GOODS-South, providing us with a rich multi-wavelength auxiliary data set, which we utilise for redshift confirmation and to estimate dust content. We use this new data to measure the faint-end slope (α) of LF(H with unprecedented precision. The data are well fit by a Schechter function and also a single power-law, yielding and , respectively. Thus we are able to confirm the steepening of α from low- to high-z predicted by a number of authors and observed at other wavelengths. We combine our LF data-points with those from a much shallower but wider survey at (Geach et al. 2008), constructing a LF spanning a factor of 50 in luminosity. Re-fitting the Schechter parameters, we obtain erg s-1; Mpc-3; . We integrate over LF(H and apply a correction for dust attenuation to determine the instantaneous cosmic star-formation rate density at without assuming α or extrapolating it from lower-z. Our measurement of is yr-1 Mpc-3, integrated over a range of .
Key words: galaxies: fundamental parameters / galaxies: high-redshift / galaxies: evolution / galaxies: starburst / galaxies: luminosity function, mass function
© ESO, 2010
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.