EXTENDED Lyα EMISSION AROUND STAR-FORMING GALAXIES

Lyα Driven Outflows Around Star Forming Galaxies

We present accurate Monte-Carlo calculations of Lyα radiation pressure in a range of models which represent galaxies during various epochs of our Universe. We show that the radiation force that Lyα photons exert on hydrogen gas in the neutral intergalactic medium (IGM), that surrounds minihalos that host the first stars, may exceed gravity by orders of magnitude and drive supersonic winds. Lyα ...

X-ray emission from star-forming galaxies

Lyα Absorption around Nearby Galaxies

We have used STIS aboard HST to search for Lyα absorption lines in the outer regions of eight nearby galaxies using background QSOs and AGN as probes. Lyα lines are detected within a few hundred km s−1 of the systemic velocity of the galaxy in all cases. We conclude that a background line of sight which passes within 26 − 200 h−1 kpc of a foreground galaxy is likely to intercept low column dens...

The Lyα Forest Around High Redshift Galaxies

Motivated by the relative lack of neutral hydrogen around Lyman Break Galaxies deduced from recent observations, we investigate the properties of the Lyα forest around high redshift galaxies. The study is based on improved numerical SPH simulations implementing, in addition to standard processes, a new scheme for multiphase and outflow physics description. Although on large scales our simulatio...

On the influence of physical galaxy properties on Lyα escape in star-forming galaxies

Context. Among the different observational techniques used to select high-redshift galaxies, the hydrogen recombination line Lymanalpha (Lyα) is of particular interest as it gives access to the measurement of cosmological quantities such as the star formation rate of distant galaxy populations. However, the interpretation of this line and the calibration of such observables is still subject to ...