%0 Generic %1 kim2015evidence %A Kim, Tae-Sun %A Carswell, Robert F. %A Ranquist, Drake %D 2015 %K absorbers bimodality column low metallicity %T Evidence of bimodal physical properties of intervening, optically-thin CIII absorbers at z ~ 2.5 %U http://arxiv.org/abs/1512.01050 %X We present the Voigt profile analysis of 132 intervening CIV+CIII components associated with optically-thin HI absorbers at 2.1 < z < 3.4 in the 19 high-quality UVES/VLT and HIRES/Keck QSO spectra. For log N(CIV) = 11.7, 14.1, N(CIII) is proportional to N(CIV) with an exponent (1.42 +- 0.11) and < N(CIII)/N(CIV) > = 1.0 +- 0.3 with a negligible redshift evolution. For 54 CIV components tied (aligned) with HI at log N(HI) = 12.2, 16.0 and log N(CIV) = 11.8, 13.8, the gas temperature T_b estimated from absorption line widths is well-approximated to a Gaussian peaking at log T_b ~ 4.4 +- 0.3 for log T_b = 3.5, 5.5, with a negligible non-thermal contribution. For 32 of 54 tied HI+CIV pairs, also tied with CIII at log N(CIII) = 11.7, 13.8, we ran both photoionisation equilibrium (PIE) and non-PIE (using a fixed temperature T_b) Cloudy models for the Haardt-Madau QSO+galaxy 2012 UV background. We find evidence of bimodality in observed and derived physical properties. High-metallicity branch absorbers have a carbon abundance C/H_temp > -1.0, a line-of-sight length L_temp < 20 kpc, and a total (neutral and ionised) hydrogen volume density log n(H, temp) = -4.5, -3.3 and and log T_b = 3.9, 4.5. Low-metallicity branch absorbers have C/H_temp < -1.0, L_temp = 20, 480 kpc and log n(H, temp) = -5.2, -4.3 and log T_b ~ 4.5. High-metallicity branch absorbers seem to be originated from extended disks, inner halos or outflowing gas of intervening galaxies, while low-metallicity absorbers are produced by galactic halos or the surrounding IGM filament.

@misc{kim2015evidence, abstract = {We present the Voigt profile analysis of 132 intervening CIV+CIII components associated with optically-thin HI absorbers at 2.1 < z < 3.4 in the 19 high-quality UVES/VLT and HIRES/Keck QSO spectra. For log N(CIV) = [11.7, 14.1], N(CIII) is proportional to N(CIV) with an exponent (1.42 +- 0.11) and < N(CIII)/N(CIV) > = 1.0 +- 0.3 with a negligible redshift evolution. For 54 CIV components tied (aligned) with HI at log N(HI) = [12.2, 16.0] and log N(CIV) = [11.8, 13.8], the gas temperature T_b estimated from absorption line widths is well-approximated to a Gaussian peaking at log T_b ~ 4.4 +- 0.3 for log T_b = [3.5, 5.5], with a negligible non-thermal contribution. For 32 of 54 tied HI+CIV pairs, also tied with CIII at log N(CIII) = [11.7, 13.8], we ran both photoionisation equilibrium (PIE) and non-PIE (using a fixed temperature T_b) Cloudy models for the Haardt-Madau QSO+galaxy 2012 UV background. We find evidence of bimodality in observed and derived physical properties. High-metallicity branch absorbers have a carbon abundance [C/H]_temp > -1.0, a line-of-sight length L_temp < 20 kpc, and a total (neutral and ionised) hydrogen volume density log n(H, temp) = [-4.5, -3.3] and and log T_b = [3.9, 4.5]. Low-metallicity branch absorbers have [C/H]_temp < -1.0, L_temp = [20, 480] kpc and log n(H, temp) = [-5.2, -4.3] and log T_b ~ 4.5. High-metallicity branch absorbers seem to be originated from extended disks, inner halos or outflowing gas of intervening galaxies, while low-metallicity absorbers are produced by galactic halos or the surrounding IGM filament.}, added-at = {2015-12-04T10:39:33.000+0100}, author = {Kim, Tae-Sun and Carswell, Robert F. and Ranquist, Drake}, biburl = {https://www.bibsonomy.org/bibtex/2c93e169fc851e3927cd05cbfb50478d3/miki}, description = {[1512.01050] Evidence of bimodal physical properties of intervening, optically-thin CIII absorbers at z ~ 2.5}, interhash = {9f7a01ca9c56e5452bc08a45b0b1f2dd}, intrahash = {c93e169fc851e3927cd05cbfb50478d3}, keywords = {absorbers bimodality column low metallicity}, note = {cite arxiv:1512.01050Comment: Accepted for publication in MNRAS. For the published paper: 29 pages, 24 figures, 7 tables. For online data, 53 velocity plots (c3_velplot.pdf), profile fitting line parameters (table2.dat, table2.pdf)}, timestamp = {2015-12-04T10:40:03.000+0100}, title = {Evidence of bimodal physical properties of intervening, optically-thin CIII absorbers at z ~ 2.5}, url = {http://arxiv.org/abs/1512.01050}, year = 2015 }