The effect of feedback on the emission properties of the warm-hot intergalactic medium

M. Roncarelli, N. Cappelluti, S. Borgani, E. Branchini, L. Moscardini

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


At present, 30-40per cent of the baryons in the local Universe is still undetected. According to theoretical predictions, this gas should reside in filaments filling the large-scale structure (LSS) in the form of a warm-hot intergalactic medium (WHIM), at temperatures 105-107K, thus emitting in the soft X-ray energies via free-free interaction and line emission from heavy elements. In this work, we characterize the properties of the X-ray emission of the WHIM, and the LSS in general, focusing on the influence of different physical mechanisms, namely galactic winds (GWs), black hole feedback and star formation, and providing estimates of possible observational constraints. To this purpose, we use a set of cosmological hydrodynamical simulations that include a self-consistent treatment of star formation and chemical enrichment of the intergalactic medium, which allows us to follow the evolution of different metal species. We construct a set of simulated light cones to make predictions of the emission in the 0.3-10keV energy range. We obtain that GWs increase the emission of both galaxy clusters and WHIM by a factor of 2. The amount of oxygen at average temperature and, consequently, the amount of expected bright Ovii and Oviii lines are increased by a factor of 3 due to GWs and by 20per cent when assuming a top-heavy initial mass function. We compare our results with current observational constraints and find that the emission from faint groups and WHIM should account for half to all of the unresolved X-ray background in the 1-2keV band.

Original languageEnglish (US)
Pages (from-to)1012-1025
Number of pages14
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
StatePublished - Aug 2012
Externally publishedYes


  • Cosmology: theory
  • Large-scale structure of Universe
  • X-rays: diffuse background
  • X-rays: galaxies: clusters

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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