The thermal history of the intergalactic medium at 3.9 ≤ z ≤ 4.3
Abstract
A new determination of the temperature of the intergalactic medium (IGM) over 3.9 ≤ z ≤ 4.3 is presented. We applied the curvature method on a sample of 10 high-resolution quasar spectra from the Ultraviolet and Visual Echelle Spectrograph on the VLT/ESO. We measured the temperature at mean density by determining the temperature at the characteristic overdensity, which is tight function of the absolute curvature irrespective of γ. Under the assumption of fiducial value of γ = 1.4, we determined the values of temperatures at mean density T0 = 7893+1417-1226 K and T0 = 8153+1224-993 K for redshift range of 3.9 ≤ z ≤ 4.1 and 4.1 ≤ z ≤ 4.3 , respectively. Even though the results show no strong temperature evolution over the studied redshift range, our measurements are consistent with an IGM thermal history that includes a contribution from He II reionisation.
- Publication:
-
Publications of the Astronomical Society of Australia
- Pub Date:
- May 2023
- DOI:
- 10.1017/pasa.2023.22
- arXiv:
- arXiv:2304.05519
- Bibcode:
- 2023PASA...40...22O
- Keywords:
-
- intergalactic medium;
- quasars: absorption lines;
- cosmology: observations;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- Accepted for publication in PASA, 9 pages, 8 figures