%0 Generic %1 dodorico2013metals %A D'Odorico, V. %A Cupani, G. %A Cristiani, S. %A Maiolino, R. %A Molaro, P. %A Nonino, M. %A Centurión, M. %A Cimatti, A. %A Alighieri, S. di Serego %A Fiore, F. %A Fontana, A. %A Gallerani, S. %A Giallongo, E. %A Mannucci, F. %A Marconi, A. %A Pentericci, L. %A Viel, M. %A Vladilo, G. %D 2013 %K civ evolution igm metals %T Metals in the IGM approaching the re-ionization epoch: results from X-shooter at the VLT %U http://arxiv.org/abs/1306.4604 %X We present the results of observations taken with the X-shooter spectrograph devoted to the study of quasars at z~6. This paper focuses on the properties of metals at high redshift traced, in particular, by the C IV doublet absorption systems. Six objects were observed with resolutions ~27 and 34 km/s in the visual, and 37.5 and 53.5 km/s in the near infrared. We detected 102 C IV lines in the range: 4.35 < z < 6.2 of which 27 are above z~5. Thanks to the characteristics of resolution and spectral coverage of X-shooter, we could also detect 25 Si IV doublets associated with the C IV at z>5. The column density distribution function (CDDF) of the C IV line sample is observed to evolve in redshift for z>~ 5.3, with respect to the normalization defined by low redshift (1.5 < z <4) C IV lines. This behaviour is reflected in the redshift evolution of the C IV cosmic mass density, Omega_CIV, of lines with column density in the range 13.4 < log N(C IV) < 15, which is consistent with a drop of a factor ~2 for z>~ 5.3. Considering only the stronger C IV lines (13.8 < log N(CIV) < 15), Omega_CIV gently rises by a factor of ~10 between z~ 6.2 and z~ 1.5 with a possible flattening toward z ~0. The increase is well fitted by a power law: Omega_CIV = (2+-1)x10^-8 (1+z)/4^-3.1+-0.1. An insight into the properties of the C IV absorbers and their evolution with redshift is obtained by comparing the observed column densities of associated C IV, Si IV and C II absorptions with the output of a set of CLOUDY photo-ionization models. As already claimed by cosmological simulations, we find that C IV is a good tracer of the metallicity in the low density IGM gas at z ~ 5-6 while at z~3 it arises in gas with over-density delta~100.

@misc{dodorico2013metals, abstract = {We present the results of observations taken with the X-shooter spectrograph devoted to the study of quasars at z~6. This paper focuses on the properties of metals at high redshift traced, in particular, by the C IV doublet absorption systems. Six objects were observed with resolutions ~27 and 34 km/s in the visual, and 37.5 and 53.5 km/s in the near infrared. We detected 102 C IV lines in the range: 4.35 < z < 6.2 of which 27 are above z~5. Thanks to the characteristics of resolution and spectral coverage of X-shooter, we could also detect 25 Si IV doublets associated with the C IV at z>5. The column density distribution function (CDDF) of the C IV line sample is observed to evolve in redshift for z>~ 5.3, with respect to the normalization defined by low redshift (1.5 < z <4) C IV lines. This behaviour is reflected in the redshift evolution of the C IV cosmic mass density, Omega_CIV, of lines with column density in the range 13.4 < log N(C IV) < 15, which is consistent with a drop of a factor ~2 for z>~ 5.3. Considering only the stronger C IV lines (13.8 < log N(CIV) < 15), Omega_CIV gently rises by a factor of ~10 between z~ 6.2 and z~ 1.5 with a possible flattening toward z ~0. The increase is well fitted by a power law: Omega_CIV = (2+-1)x10^{-8} [(1+z)/4]^{-3.1+-0.1}. An insight into the properties of the C IV absorbers and their evolution with redshift is obtained by comparing the observed column densities of associated C IV, Si IV and C II absorptions with the output of a set of CLOUDY photo-ionization models. As already claimed by cosmological simulations, we find that C IV is a good tracer of the metallicity in the low density IGM gas at z ~ 5-6 while at z~3 it arises in gas with over-density delta~100.}, added-at = {2013-06-20T11:40:47.000+0200}, author = {D'Odorico, V. and Cupani, G. and Cristiani, S. and Maiolino, R. and Molaro, P. and Nonino, M. and Centurión, M. and Cimatti, A. and Alighieri, S. di Serego and Fiore, F. and Fontana, A. and Gallerani, S. and Giallongo, E. and Mannucci, F. and Marconi, A. and Pentericci, L. and Viel, M. and Vladilo, G.}, biburl = {https://www.bibsonomy.org/bibtex/2c3a743d6db9039bcc5c5af3e4444bad0/miki}, description = {[1306.4604] Metals in the IGM approaching the re-ionization epoch: results from X-shooter at the VLT}, interhash = {03fb00b8aaf14cee7fbbdbfb5af0271f}, intrahash = {c3a743d6db9039bcc5c5af3e4444bad0}, keywords = {civ evolution igm metals}, note = {cite arxiv:1306.4604Comment: Paper submitted to MNRAS. Revised version after referee report. 39 pages, 9 Tables, 33 Figures}, timestamp = {2013-06-20T11:40:47.000+0200}, title = {Metals in the IGM approaching the re-ionization epoch: results from X-shooter at the VLT}, url = {http://arxiv.org/abs/1306.4604}, year = 2013 }