C.D.S. - SIMBAD4 rel 1.7 - 2020.12.02CET11:12:15

2017A&A...606A..56C - Astronomy and Astrophysics, volume 606A, 56-56 (2017/10-1)

The potential of tracing the star formation history with H I 21-cm in intervening absorption systems.


Abstract (from CDS):

Unlike the neutral gas density, which remains largely constant over redshifts of 0≥z≥5, the star formation density, ψ*, exhibits a strong redshift dependence, increasing from the present day before peaking at a redshift of z~=2.5. Thus, there is a stark contrast between the star formation rate and the abundance of raw material available to fuel it. However, using the ratio of the strength of the H I 21-cm absorption to the total neutral gas column density to quantify the spin temperature, Tspin, of the gas, it has recently been shown that 1/Tspin may trace ψ*. This would be expected on the grounds that the cloud of gas must be sufficiently cool to collapse under its own gravity. This, however, relies on very limited data and so here we explore the potential of applying the above method to absorbers for which individual column densities are not available (primarily Mg II absorption systems). By using the mean value as a proxy to the column density of the gas at a given redshift, we do, again, find that 1/Tspin (degenerate with the absorber-emitter size ratio) traces ψ*. If confirmed by higher redshift data, this could offer a powerful tool for future surveys for cool gas throughout the Universe with the Square Kilometre Array.

Abstract Copyright: © ESO, 2017

Journal keyword(s): galaxies: high-redshift - galaxies: star formation - Galaxy: evolution - galaxies: ISM - quasars: absorption lines - radio lines: galaxies - radio lines: galaxies

Simbad objects: 3

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Number of rows : 3

N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
1 ICRF J074110.7+311200 Sy1 07 41 10.7032630079 +31 12 00.232776104   17.02 16.89 16.322   ~ 415 1
2 QSO J0850+5159 QSO 08 50 42.2442415678 +51 59 11.651027176   19.92 19.41     ~ 40 1
3 QSO J2340-0053 QSO 23 40 23.6702895509 -00 53 26.997605159   18.26 17.93     ~ 80 0

    Equat.    Gal    SGal    Ecl

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