Abstract
We use a high-resolution cosmological simulation that includes hydrodynamics, multiphase star formation, and galactic winds to predict the distribution of metal line emission at z ~ 0 from the intergalactic medium (IGM). We focus on two ultraviolet doublet transitions, O VI λλ1032, 1038 and C IV λλ1548, 1551. Emission from filaments with moderate overdensities is orders of magnitude smaller than the background, but isolated emission from enriched dense regions with T ~ 105-105.5 K and characteristic size ~50-100 kpc can be detected above the background. We show that the emission from these regions is substantially greater when we use the metallicities predicted by the simulation (which includes enrichment through galactic winds) than when we assume a uniform IGM metallicity. Luminous regions correspond to volumes that have recently been influenced by galactic winds. We also show that the line emission is clustered on scales ~1 h-1 Mpc. We argue that although these transitions are not effective tracers of the warm-hot intergalactic medium, they do provide a route to study the chemical enrichment of the IGM and the physics of galactic winds.
Highlights
The modern paradigm for cosmological structure formation, the cold dark matter model, has had admirable success in describing both the formation of galaxies and the distribution of matter on larger scales
We use a high-resolution cosmological simulation that includes hydrodynamics, multiphase star formation, and galactic winds to predict the distribution of metal line emission at z ∼ 0 from the intergalactic medium (IGM)
Denser, and more enriched than the surrounding voids so they stand out clearly in both transitions. This is a simple consequence of the metal dispersal mechanism: winds must begin in galaxies which in turn lie inside overdense regions. (Note, that the metallicity is quite inhomogeneous even within filaments.) Second, the O VI maps better trace the diffuse filamentary structure of the IGM
Summary
The modern paradigm for cosmological structure formation, the cold dark matter model, has had admirable success in describing both the formation of galaxies and the distribution of matter on larger scales. We will contrast a uniform metallicity with the metal distribution predicted by the simulation, which includes winds from massive galaxies Aside from enrichment, another key process affecting IGM gas is shock heating: simulations show that a large fraction ( 20%) of intergalactic gas has 105 K T 107 K (Cen & Ostriker 1999; Davé et al 2001). Tripp et al (2000) found a large number of low-redshift O VI λ1032 absorbers along one line of sight, suggesting that 10% of baryons are in the WHIM phase These absorption studies suffer from the same drawbacks mentioned above and do not provide a direct picture of WHIM gas.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
