Skip to main content
Article thumbnail
Location of Repository

Astronomy Astrophysics

By E. Vanzella, S. Cristiani, S. Arnouts, M. Dennefeld, A. Fontana, A. Grazian, M. Nonino, P. Petitjean and P. Saracco

Abstract

Abstract. We report on low-resolution multi-object spectroscopy of 65 objects from I(AB) � 20 to I(AB) � 25 in the HDF-S obtained with the VLT Focal Reducer/low dispersion Spectrograph (FORS2). 18 objects belong to the HDF-S proper, i.e. the WFPC2 deep area. 15 high-redshift galaxies with 2.0 < z < 3.5 (10 in the HDF-S proper) have been identified. The spectroscopic redshifts are in good agreement with the photometric ones derived from a χ 2 minimization technique comparing the observed spectral energy distribution with synthetic libraries and with a new neural network (NN) approach. The dispersion with the former method is σz = 0.16 whereas the latter provides σz = 0.13. No “catastrophic ” difference is encountered. The inferred star formation rates of the individual objects range from tens to a few hundreds of M ⊙ yr −1 and the global star formation rate of the Universe at < z> � 2.4 is estimated to be 0.15 M ⊙ yr −1 Mpc −3 with a statistical error of 0.04. Evidence for large-scale structure is found with two groups ’ redshifts observed at z � 2.1 andz � 2.7 and a pronounced low redshift peak around z � 0.58. An elliptical galaxy lensing a background object turns out to be at a redshift z = 0.577

Year: 2009
OAI identifier: oai:CiteSeerX.psu:10.1.1.134.3637
Provided by: CiteSeerX
Download PDF:
Sorry, we are unable to provide the full text but you may find it at the following location(s):
  • http://citeseerx.ist.psu.edu/v... (external link)
  • http://www.aanda.org/articles/... (external link)
  • Suggested articles


    To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.