Title:	Diffuse x-ray emission from star-forming galaxies
Authors:	Sarkar, Kartick Chandra Nath, Biman B. Sharma, Prateek Shchekinov, Yuri
Issue Date:	20-Feb-2016
Publisher:	IOP Publishing Ltd for the American Astronomical Society
Citation:	Astrophysical Journal Letters, 2016, Vol. 818, pL24
Abstract:	We study the diffuse X-ray luminosity (LX) of star-forming galaxies using two-dimensional axisymmetric hydrodynamical simulations and analytical considerations of supernovae-(SNe-)driven galactic outflows. We find that the mass loading of the outflows, a crucial parameter for determining the X-ray luminosity, is constrained by the availability of gas in the central star-forming region, and a competition between cooling and expansion. We show that the allowed range of the mass loading factor can explain the observed scaling of LX with star formation rate (SFR) as ${L}_{{\rm{X}}}\quad \propto $ SFR2 for SFR $\gtrsim \quad 1$ ${M}_{\odot }$ yr−1, and a flatter relation at low SFRs. We also show that the emission from the hot circumgalactic medium (CGM) in the halo of massive galaxies can explain the large scatter in the ${L}_{{\rm{X}}}\mbox{--}\mathrm{SFR}$ relation for low SFRs (lesssimfew ${M}_{\odot }$ yr−1). Our results suggest that galaxies with small SFRs and large diffuse X-ray luminosities are excellent candidates for the detection of the elusive CGM.
Description:	Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)
URI:	http://hdl.handle.net/2289/6419
ISSN:	2041-8205 2041-8213 (Online)
Alternative Location:	http://adsabs.harvard.edu/abs/2016ApJ...818L..24S http://arxiv.org/abs/1601.00394 http://dx.doi.org/10.3847/2041-8205/818/2/L24
Copyright:	2016 American Astronomical Society
Appears in Collections:	Research Papers (A&A)

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