A gaseous group with unusual remote star formation

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Title: A gaseous group with unusual remote star formation
Author(s): Santiago-Figueroa, N.; Putman, M. E.; Werk, J.; Meurer, G. R.; Ryan-Weber, E.
Abstract: We present VLA 21-cm observations of the spiral galaxy ESO 481-G017 to determine the nature of remote star formation traced by an Hii region found 43 kpc and ~800 km s–1 from the galaxy center (in projection). ESO 481-G017 is found to have a 120 kpc Hi disk with a mass of 1.2 × 1010 M⊙ and UV GALEX images reveal spiral arms extending into the gaseous disk. Two dwarf galaxies with Hi masses close to 108 M⊙ are detected at distances of ~200 kpc from ESO 481-G017 and a Hi cloud with a mass of 6 × 107 M⊙ is found near the position and velocity of the remote Hii region. The Hii region is somewhat offset from the Hi cloud spatially and there is no link to ESO 481-G017 or the dwarf galaxies. We consider several scenarios for the origin of the cloud and Hii region and find the most likely is a dwarf galaxy that is undergoing ram pressure stripping. The Hi mass of the cloud and Hα luminosity of the Hii region (1038.1 erg s–1) are consistent with dwarf galaxy properties, and the stripping can trigger the star formation as well as push the gas away from the stars.
Publication type: Journal article
Research centre: Swinburne University of Technology. Faculty of Information and Communication Technologies. Centre for Astrophysics and Supercomputing
Source: Publications of the Astronomical Society of Australia, Vol. 28, no. 3 (2011), pp. 271-279
Publication year: 2011
FOR Code(s): 0201 Astronomical and Space Sciences
Keyword(s): Dwarf galaxies; HII regions; ISM
Publisher: CSIRO Publishing
ISSN: 1323-3580
Publisher URL: http://dx.doi.org/10.1071/as11008
Peer reviewed