Roles of radiation and ram pressure in driving galactic winds

Sharma, Mahavir; Nath, Biman B.

Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/4455

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DC Field	Value	Language
dc.contributor.author	Sharma, Mahavir	-
dc.contributor.author	Nath, Biman B.	-
dc.date.accessioned	2012-05-07T08:52:32Z	-
dc.date.available	2012-05-07T08:52:32Z	-
dc.date.issued	2012-05	-
dc.identifier.citation	Astrophysical Journal,2012, Vol. 750, p1	en
dc.identifier.issn	0004-6256	-
dc.identifier.issn	1538-3881 (Online)	-
dc.identifier.uri	http://hdl.handle.net/2289/4455	-
dc.description	Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)	en
dc.description.abstract	We study gaseous outflows from disk galaxies driven by the combined effects of ram pressure on cold gas clouds and radiation pressure on dust grains. Taking into account the gravity due to disk, bulge, and dark matter halo, and assuming continuous star formation in the disk, we show that radiation or ram pressure alone is not sufficient to drive escaping winds from disk galaxies and that both processes contribute. We show that in the parameter space of star formation rate (SFR) and rotation speed of galaxies the wind speed in galaxies with rotation speeds vc <= 200 km s-1 and SFR <= 100 M sun yr-1 has a larger contribution from ram pressure, and that in high-mass galaxies with large SFR radiation from the disk has a greater role in driving galactic winds. The ratio of wind speed to circular speed can be approximated as {v_w / v_c} \sim 10^{0.7} \, [SFR/ 50 \, {M_{\odot } \,yr^{-1}}] ^{0.4} \ [{v_c/ 120\, km\,s^{-1}}]^ {-1.25}. We show that this conclusion is borne out by observations of galactic winds at low and high redshift and also of circumgalactic gas. We also estimate the mass loading factors under the combined effect of ram and radiation pressure, and show that the ratio of mass-loss rate to SFR scales roughly as v -1 c Σ g -1, where Σ g is the gas column density in the disk.	en
dc.language.iso	en	en
dc.publisher	American Astronomical Society	en
dc.relation.uri	http://adsabs.harvard.edu/abs/2012ApJ...750...55S	en
dc.relation.uri	http://arxiv.org/abs/1112.3447	en
dc.relation.uri	http://dx.doi.org/10.1088/0004-637X/750/1/55	en
dc.rights	2012 The American Astronomical Society	en
dc.subject	galaxies: evolution	en
dc.subject	galaxies: starburst	en
dc.subject	intergalactic medium	en
dc.title	Roles of radiation and ram pressure in driving galactic winds	en
dc.type	Article	en
Appears in Collections:	Research Papers (A&A)

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