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arXiv · 1604.01397

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
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Abstract

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 10^10-10^13 Msun). 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 (L_X), 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 (<~10^11 Msun) 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 10^13 Msun. For halo masses <~10^12 Msun, L_X 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 >~10^13 Msun, on the other hand, L_X is much less variable and not correlated with the SFR, because the emission originates from the quasi-hydrostatic, virialized halo gas.

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Freeke van de Voort, Eliot Quataert, Philip F. Hopkins, Claude-André Faucher-Giguère, Robert Feldmann, Dušan Kereš, T. K. Chan, Zachary Hafen. 2016-09-12. The impact of stellar feedback on hot gas in galaxy haloes: the Sunyaev-Zel'dovich effect and soft X-ray emission. https://doi.org/10.1093/mnras%2Fstw2322

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