Nature of the absorbing gas associated with a galaxy group at z∼0.4 - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles Monthly Notices of the Royal Astronomical Society Year : 2017

Nature of the absorbing gas associated with a galaxy group at z∼0.4

Max Pettini
  • Function : Author
Varsha Kulkarni
  • Function : Author
Donald G. York
  • Function : Author
Lorrie Straka
  • Function : Author
Bernd Husemann
  • Function : Author


We present new Multi Unit Spectroscopic Explorer observations of quasar field Q2131-1207 with a log N(H I} = 19.50 ± 0.15 sub-damped Lyman α at zabs = 0.42980. We detect four galaxies at a redshift consistent with that of the absorber where only one was known before this study. Two of these are star-forming galaxies, while the ones further away from the quasar (>140 kpc) are passive galaxies. We report the metallicities of the H II regions of the closest objects (12 + log(O/H) = 8.98 ± 0.02 and 8.32 ± 0.16) to be higher or equivalent within the errors to the metallicity measured in absorption in the neutral phase of the gas (8.15 ± 0.20). For the closest object, a detailed morphokinematic analysis indicates that it is an inclined large rotating disc with Vmax = 200 ± 3 km s-1. We measure the masses to be Mdyn = 7.4 ± 0.4 × 1010 M and Mhalo = 2.9 ± 0.2 × 1012 M. Some of the gas seen in absorption is likely to be corotating with the halo of that object, possibly due to a warped disc. The azimuthal angle between the quasar line-of-sight and the projected major axis of the galaxy on the sky is 12° ± 1° which indicates that some other fraction of the absorbing gas might be associated with accreting gas. This is further supported by the galaxy to gas metallicity difference. Based on the same arguments, we exclude outflows as a possibility to explain the gas in absorption. The four galaxies form a large structure (at least 200 kpc wide) consistent with a filament or a galaxy group so that a fraction of the absorption could be related to intragroup gas.
Fichier principal
Vignette du fichier
stw2444.pdf (3.15 Mo) Télécharger le fichier
Origin : Publisher files allowed on an open archive

Dates and versions

insu-03666221 , version 1 (12-05-2022)



Céline Péroux, Hadi Rahmani, Samuel Quiret, Max Pettini, Varsha Kulkarni, et al.. Nature of the absorbing gas associated with a galaxy group at z∼0.4. Monthly Notices of the Royal Astronomical Society, 2017, 464, pp.2053-2065. ⟨10.1093/mnras/stw2444⟩. ⟨insu-03666221⟩
7 View
12 Download



Gmail Facebook X LinkedIn More