2021A&A...651A..78N


Query : 2021A&A...651A..78N

2021A&A...651A..78N - Astronomy and Astrophysics, volume 651A, 78-78 (2021/7-1)

Sharpening quasar absorption lines with ESPRESSO. Temperature of warm gas at z ∼ 2, constraints on the Mg isotopic ratio, and structure of cold gas at z ∼ 0.5.

NOTERDAEME P., BALASHEV S., LEDOUX C., DUCHOQUET G., LOPEZ S., TELIKOVA K., BOISSE P., KROGAGER J.-K., DE CIA A. and BERGERON J.

Abstract (from CDS):


Aims. We aim to study several key physical properties of quasar absorption-line systems that are subtly encoded in their absorption profiles and have not yet been thoroughly investigated or constrained.
Methods. We analysed a high-resolution (R=140000) spectrum of the bright quasar HE 0001-2340 (zem=2.26) obtained with ESPRESSO, which was recently installed at the Very Large Telescope. We analysed three systems at z=0.45, z=1.65, and z=2.19 using multiple-component Voigt-profile fitting. We also compared our spectrum with those obtained with VLT/UVES, covering a total period of 17 years.
Results. We disentangle turbulent and thermal broadening in many components spread over about 400km/s in the z≃2.19 sub-damped Lyman-α system. We derive an average temperature of 16000±1300K, which is about twice the canonical value of the warm neutral medium in the Galactic interstellar medium (ISM). A comparison with other high-z, low-metallicity absorbers reveals an anti-correlation between gas temperature and total HI column density. Although requiring confirmation, this could be the first observational evidence of a thermal decrease with galactocentric distance; in other words, we may be witnessing a thermal transition between the circumgalactic medium and the coolerISM. We revisit the Mg isotopic ratios at z=0.45 and z=1.65 and constrain them to be ξ=(26Mg+25Mg)/24Mg<0.6 and <1.4 in these two systems, respectively. These values are consistent with the standard solar ratio; that is, we do not confirm strong enhancement of heavy isotopes previously inferred from UVES data. Finally, we confirm the partial coverage of the quasar emission-line region by a FeI-bearing cloud in the z=0.45 system and present evidence for velocity substructure of the gas that has Doppler parameters of the order of only ∼0.3km/s. This agrees well with the low kinetic temperature of T∼100K inferred from modelling of the gas physical conditions.Conslusions. This work demonstrates the unique insight provided by high-fidelity, high-resolution optical spectrographs on large telescopes when used to investigate the thermal state of the gas in and around galaxies as well as its spatial and velocity structure on small scales, and to constrain the associated stellar nucleosynthetic history.

Abstract Copyright: © P. Noterdaeme et al. 2021

Journal keyword(s): quasars: absorption lines - quasars: individual: HE 0001-2340

Simbad objects: 12

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Number of rows : 12
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 QSO J0003-2323 QSO 00 03 44.9144535192 -23 23 55.073021280     16.7     ~ 75 0
2 QSO J0035-0918 QSO 00 35 01.8852012984 -09 18 17.640206928   19.32 19.12     ~ 55 0
3 QSO B0105+1619 QSO 01 08 06.4234637880 +16 35 49.968976200   16.9       ~ 59 0
4 QSO J0407-4410 QSO 04 07 18.0880236912 -44 10 13.983623724   17.6 17.6     ~ 95 0
5 QSO B0913+0715 QSO 09 16 13.9618240848 +07 02 24.497778588     17.1     ~ 102 0
6 CSO 38 QSO 10 11 55.5947671920 +29 41 41.595330804   16.28 16.05     ~ 109 0
7 QSO B1243+3047 QSO 12 46 10.800 +30 31 17.00     17.00     ~ 37 0
8 QSO J1358+6522 QSO 13 58 42.9160217208 +65 22 36.664532364   19.53 19.06     ~ 55 0
9 QSO J1419+0829 QSO 14 19 50.5527303624 +08 29 48.295169592   19.39 19.07     ~ 48 0
10 QSO B1442+2931 QSO 14 44 53.5398146832 +29 19 05.691187272   16.59 16.38     ~ 79 0
11 QSO J1558-0031 QSO 15 58 10.1642192448 -00 31 20.035621812   18.07 17.80     ~ 57 0
12 QSO B2206-1959 QSO 22 09 00.6950774976 -19 44 19.743416484     18.65     ~ 83 0

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2023.01.27-23:07:27

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