Аннотация
We use cosmological simulations from the Feedback In Realistic Environments
(FIRE) project, which implement a comprehensive set of stellar feedback
processes, to study ultra-violet (UV) metal line emission from the
circum-galactic medium of high-redshift (z = 2-4) galaxies. Our simulations
cover the halo mass range Mh~2x10^11 - 8.5x10^12 Msun at z = 2, representative
of Lyman break galaxies. Of the transitions we analyze, the low-ionization C
III (977 A) and Si III (1207 A) emission lines are the most luminous, with C IV
(1548 A) and Si IV (1394 A) also showing interesting spatially-extended
structures that should be detectable by current and upcoming integral field
spectrographs such as the Multi Unit Spectroscopic Explorer (MUSE) on the Very
Large Telescope and Keck Cosmic Web Imager (KCWI). The more massive halos are
on average more UV-luminous. The UV metal line emission from galactic halos in
our simulations arises primarily from collisionally ionized gas and is strongly
time variable, with peak-to-trough variations of up to ~2 dex. The peaks of UV
metal line luminosity correspond closely to massive and energetic mass outflow
events, which follow bursts of star formation and inject sufficient energy into
galactic halos to power the metal line emission. The strong time variability
implies that even some relatively low-mass halos may be detectable in deep
observations with current generation instruments. Conversely, flux-limited
samples will be biased toward halos whose central galaxy has recently
experienced a strong burst of star formation.
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