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The lack of intense Lyman~alpha in ultradeep spectra of z=7 candidates in GOODS-S: imprint of reionization?
Astrophysical Journal (2010)
  • A. Fontana
  • E. Vanzella
  • L. Pentericci
  • M. Castellano
  • Mauro Giavalisco, University of Massachusetts - Amherst
  • A. Grazian
  • K. Boutsia
  • S. Christiani
  • M. Dickinson
  • E. Giallongo
  • M. Maiolino
  • A. Moorwood
  • P. Santini
We present ultradeep optical spectroscopy obtained with FORS2 on VLT of seven Lyman-break galaxy (LBG) candidates at z>6.5 selected in the GOODS-S field from Hawk-I/VLT and WFC3/HST imaging. For one galaxy we detect a low significance emission line (S/N< 7), located at 9691.5 +/- 0.5A and with flux 3.4 x 10^(-18)erg/cm^2/s. If identified as Lyman alpha, it places the LBG at redshift z=6.972+/- 0.002, with a rest-frame equivalent width EW}=13A. Using Monte Carlo simulations and conservative EW distribution functions at 210 is ~ 2%, and that of observing only one galaxy out of seven with S/N=5 is ~4%, but these can be as small as ~1E-3, depending on the details of the EW distribution. We conclude that either a significant fraction of the candidates is not at high redshift or that some physical mechanism quenches the Lyman alpha emission emerging from the galaxies at z>6.5, abruptly reversing the trend of the increasing fraction of strong emitters with increasing redshift observed up to z~ 6.5. We discuss the possibility that an increasingly neutral intergalactic medium is responsible for such quenching.
  • galaxies: distances and redshifts,
  • galaxies: high-redshift,
  • galaxies: formation
Publication Date
Publisher Statement
This paper was harvested from and ArXiv identifier is arXiv:1010.2754
Citation Information
A. Fontana, E. Vanzella, L. Pentericci, M. Castellano, et al.. "The lack of intense Lyman~alpha in ultradeep spectra of z=7 candidates in GOODS-S: imprint of reionization?" Astrophysical Journal (2010)
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