The impact of stellar feedback on hot gas in galaxy haloes: The Sunyaev-Zel'dovich effect and soft X-ray emission

Freeke van de Voort, Eliot Quataert, Philip F. Hopkins, Claude André Faucher-Giguère, Robert Feldmann, Dušan Kereš, T. K. Chan, Zachary Hafen

Research output: Contribution to journalArticlepeer-review

45 Scopus citations


The thermal Sunyaev-Zel'dovich (SZ) effect and soft X-ray emission are routinely observed around massive galaxies and in galaxy groups and clusters. We study these observational diagnostics of galaxy haloes for a suite of cosmological 'zoom-in' simulations from the 'Feedback In Realistic Environments' project, which spans a large range in halo mass (1010-13M). We explore the effect of stellar feedback on the hot gas observables. The properties of our simulated groups, such as baryon fractions, SZ flux, and X-ray luminosities (LX), are broadly consistent with existing observations, even though feedback from active galactic nuclei is not included. We make predictions for future observations of lower mass objects for both SZ and diffuse X-ray measurements, finding that they are not just scaled-down versions of massive galaxies, but more strongly affected by galactic winds driven by star formation. Low-mass haloes (≲1011 M) retain a low fraction of their baryons, which results in a strong suppression of the SZ signal. Our simulations therefore predict a scaling with halo mass that is steeper than self-similar for haloes less massive than 1013M. For halo masses≲1012 M, LX is time variable and correlated primarily with the star formation rate (SFR). For these objects, the diffuse X-ray emission is powered mostly by galactic winds and the gas dominating the X-ray emission is flowing out with radial velocities close to the halo's circular velocity. For halo masses ≳1013 M, on the other hand, LX is much less variable and not correlated with the SFR, because the emission originates from the quasi-hydrostatic, virialized halo gas.

Original languageEnglish (US)
Pages (from-to)4533-4544
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
StatePublished - Dec 21 2016
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Galaxies: evolution
  • Galaxies: formation
  • Galaxies: haloes
  • Intergalactic medium
  • Methods: numerical
  • X-rays: galaxies


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