Published in

Springer Verlag, Astrophysics and Space Science, 2(350), p. 741-754

DOI: 10.1007/s10509-013-1753-2

Links

Tools

Export citation

Search in Google Scholar

Spaxel Analysis: Probing the Physics of Star Formation in Ultraluminous Infrared Galaxies

This paper is available in a repository.
This paper is available in a repository.

Full text: Download

Green circle
Preprint: archiving allowed
Green circle
Postprint: archiving allowed
Red circle
Published version: archiving forbidden
Data provided by SHERPA/RoMEO

Abstract

This paper presents a detailed spectral pixel (spaxel) analysis of the ten Luminous Infrared Galaxies (LIRGs) previously observed with the Wide Field Spectrograph (WiFeS), an integral field spectrograph mounted on the ANU 2.3m telescope, and for which an abundance gradient analysis has already been presented by Rich et al. (2012). Here we use the strong emission line analysis techniques developed by Dopita et al. (2013) to measure the ionisation parameter and the oxygen abundance in each spaxel. In addition, we use the observed H$α$ flux to determine the surface rate of star formation ($M_{⊙}$ yr$^{-1}$ kpc$^{-2}$) and use the [\ion{S}{2}] $λλ6717/6731$ ratio to estimate the local pressure in the ionised plasma. We discuss the correlations discovered between these physical quantities, and use them to infer aspects of the physics of star formation in these extreme star forming environments. In particular, we find a correlation between the star formation rate and the inferred ionisation parameter. We examine the possible reasons for this correlation, and determine that the most likely explanation is that the more active star forming regions have a different distribution of molecular gas which favour higher ionisation parameters in the ionised plasma. ; Comment: 17 pages, 16 figures, accepted for publication in Astrophysics and Space Science