Open AccessThe cold neutral phase of the interstellar medium in high redshift galaxies
Author(s) -
S. A. Balashev,
В. В. Клименко,
P. Noterdaeme,
Jens-Kristian Krogager,
C. Ledoux,
A. V. Ivanchik,
Д. А. Варшалович,
P. Petitjean
Publication year - 2019
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1400/2/022030
Subject(s) - physics , mean kinetic temperature , redshift , galaxy , astrophysics , interstellar medium , excitation , spectrograph , ionization , atomic physics , hydrogen , excitation temperature , rotational temperature , infrared , spectral line , emission spectrum , astronomy , ion , quantum mechanics
We present the results of spectroscopic analysis of seven new H 2 -bearing damped Ly- systems in redshift range z=2.5 − 3. These systems were originally selected from SDSS catalog using a direct search for H 2 and followed up with X-SHOOTER spectrograph at 8-m Very Large Telescope observatory. We measured the column densities of H I , H 2 on various rotational levels, and metals species in different ionization stages and excitation levels. We used the rotational excitation of H 2 molecules together with the fine-structure levels of neutral carbon to constrain the physical conditions in the associated medium. We found typical values for the kinetic temperature T ∼ 80 − 120 K, hydrogen density n H ∼ 30 − 400 cm −3 and UV radiation field ξ UV ∼ 0.4 − 5 times of the Draine field. These values along with estimated thermal pressure are in agreement with expected values from the theoretical calculation of the cold neutral interstellar medium.