%0 Generic %1 Boutsia2011 %A Boutsia, K. %A Grazian, A. %A Giallongo, E. %A Fontana, A. %A Pentericci, L. %A Castellano, M. %A Zamorani, G. %A Mignoli, M. %A Vanzella, E. %A Fiore, F. %A Lilly, S. J. %A Gallozzi, S. %A Testa, V. %A Paris, D. %A Santini, P. %D 2011 %K escape_fraction ionization reionization %T A low escape fraction of ionizing photons of L>L* Lyman break galaxies at z=3.3 %U http://arxiv.org/abs/1104.5237 %X We present an upper limit for the relative escape fraction (f_esc^rel) of ionizing radiation at z~3.3 using a sample of 11 Lyman Break Galaxies (LBGs) with deep imaging in the U band obtained with the Large Binocular Camera, mounted on the prime focus of the Large Binocular Telescope. We selected 11 LBGs with secure redshift in the range 3.27<z<3.35, from 3 independent fields. We stacked the images of our sources in the R and U band, which correspond to an effective rest-frame wavelength of 1500\AA and 900\AA respectively, obtaining a limit in the U band image of >=30.7(AB)mag at 1 sigma. We derive a 1 sigma upper limit of f_esc^rel~5%, which is one of the lowest values found in the literature so far at z~3.3. Assuming that the upper limit for the escape fraction that we derived from our sample holds for all galaxies at this redshift, the hydrogen ionization rate that we obtain (Gamma_-12<0.3 s^-1) is not enough to keep the IGM ionized and a substantial contribution to the UV background by faint AGNs is required. Since our sample is clearly still limited in size, larger z~3 LBG samples, at similar or even greater depths are necessary to confirm these results on a more firm statistical basis.

@misc{Boutsia2011, abstract = { We present an upper limit for the relative escape fraction (f_{esc}^{rel}) of ionizing radiation at z~3.3 using a sample of 11 Lyman Break Galaxies (LBGs) with deep imaging in the U band obtained with the Large Binocular Camera, mounted on the prime focus of the Large Binocular Telescope. We selected 11 LBGs with secure redshift in the range 3.27<z<3.35, from 3 independent fields. We stacked the images of our sources in the R and U band, which correspond to an effective rest-frame wavelength of 1500\AA and 900\AA respectively, obtaining a limit in the U band image of >=30.7(AB)mag at 1 sigma. We derive a 1 sigma upper limit of f_{esc}^{rel}~5%, which is one of the lowest values found in the literature so far at z~3.3. Assuming that the upper limit for the escape fraction that we derived from our sample holds for all galaxies at this redshift, the hydrogen ionization rate that we obtain (Gamma_{-12}<0.3 s^{-1}) is not enough to keep the IGM ionized and a substantial contribution to the UV background by faint AGNs is required. Since our sample is clearly still limited in size, larger z~3 LBG samples, at similar or even greater depths are necessary to confirm these results on a more firm statistical basis. }, added-at = {2011-04-29T03:12:21.000+0200}, author = {Boutsia, K. and Grazian, A. and Giallongo, E. and Fontana, A. and Pentericci, L. and Castellano, M. and Zamorani, G. and Mignoli, M. and Vanzella, E. and Fiore, F. and Lilly, S. J. and Gallozzi, S. and Testa, V. and Paris, D. and Santini, P.}, biburl = {https://www.bibsonomy.org/bibtex/2838ee19bcb20dc9e067b0bf5deb1575d/miki}, description = {[1104.5237] A low escape fraction of ionizing photons of L>L* Lyman break galaxies at z=3.3}, interhash = {38a9c9212a74b0f24223b400811862c3}, intrahash = {838ee19bcb20dc9e067b0bf5deb1575d}, keywords = {escape_fraction ionization reionization}, note = {cite arxiv:1104.5237 Comment: 15 pages, 2 figures, 1 table, accepted for publication in ApJ}, timestamp = {2011-04-29T03:12:21.000+0200}, title = {A low escape fraction of ionizing photons of L>L* Lyman break galaxies at z=3.3}, url = {http://arxiv.org/abs/1104.5237}, year = 2011 }