DIFFUSE X-RAY EMISSION FROM STAR-FORMING GALAXIES

Sarkar, Kartick C and Nath, Biman B and Sharma, Prateek and Shchekinov, Yuri (2016) DIFFUSE X-RAY EMISSION FROM STAR-FORMING GALAXIES. In: ASTROPHYSICAL JOURNAL LETTERS, 818 (2).

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Abstract

We study the diffuse X-ray luminosity (L-X) 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 L-X with star formation rate (SFR) as L-X alpha SFR2 for SFR greater than or similar to 1 M-circle dot 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-X-SFR relation for low SFRs (less than or similar to few M-circle dot 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.

Item Type:	Journal Article
Publication:	ASTROPHYSICAL JOURNAL LETTERS
Publisher:	IOP PUBLISHING LTD
Keywords:	galaxies: general; galaxies: halos; galaxies: starburst; ISM: jets and outflows; X-rays: galaxies
Department/Centre:	Division of Physical & Mathematical Sciences > Joint Astronomy Programme Division of Physical & Mathematical Sciences > Physics
Date Deposited:	02 Apr 2016 09:39
Last Modified:	02 Apr 2016 09:39
URI:	http://eprints.iisc.ac.in/id/eprint/53465

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