Abstract Details

Name: Abhisek Mohapatra
Affiliation: NIT Rourkela
Conference ID: ASI2021_315
Title : Physical conditions and redshift evolution of low-z CIII absorbers
Authors and Co-Authors : R. Srianand (Inter-University Centre for Astronomy & Astrophysics, Postbag 4, Ganeshkhind, Pune 411 007, India), Ananta C. Pradhan (Department of Physics and Astronomy, National Institute of Technology, Rourkela, Odisha 769 008, India)
Abstract Type : Oral
Abstract Category : Extragalactic Astronomy
Abstract : We present the details analysis of 99 optically thin C III absorption systems obtained from background quasar spectra at redshift, 0.2 < z < 0.9 associated with neutral hydrogen column densities in the range, 15 < log N(H I) < (cm^−2 ) < 16.2. Using photoionization models, we infer the physical conditions of these intervening optical thin absorbers. We combine the low−z and previously reported high−z (2.1 < z < 3.3) optically thin C III systems to study the redshift evolution and various correlation between the derived physical parameters. We find significant redshift evolution in number density, metallicity and line-of-sight thickness. We compare the redshift evolution of metallicity in C III systems with those of various types of absorption systems and find that the slope of [C/H] vs. z for C III absorbers is stepper compared to the redshift evolution of cosmic metallicity of the damped Lyα sample (DLAs) but consistent with that of sub−DLAs. We see evidence of two distinct [C/H] branch C III populations (low−[C/H] branch and high−[C/H] branch) in the combined CIII sample when divided appropriately in the L vs. N(C III) plane. Further studies of C III absorbers in the redshift range, 1.0 < z < 2.0 is important to map the redshift evolution of these absorbers and gain insights into the time evolution physical conditions of the circumgalactic medium.