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

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$\alpha$ flux to determine the surface rate of star formation ($M_{\odot }$ yr${}^{-1}$ kpc${}^{-2}$) and use the [\ion{S}{2}] $\lambda \lambda 6717/6731$ 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.

17 pages, 16 figures, accepted for publication in Astrophysics and Space Science

References in corpus (11)

• A systematic variation of the stellar initial mass function in early-type galaxies
• The Wide Field Spectrograph (WiFeS): Performance and Data Reduction
• The mass function of young star clusters in spiral galaxies
• Dependence of Interstellar Turbulent Pressure on Supernova Rate
• Modelling the Pan-Spectral Energy Distribution of Starburst Galaxies: II. Control of the \HII Region Parameters
• High star formation rates as the origin of turbulence in early and modern disk galaxies
• HST/STIS Spectroscopy of Five Super Star Clusters in the Starburst Galaxy M82
• The Early Expansion of Cluster Cores
• Gemini Spectroscopic Survey of Young Star Clusters in Merging/Interacting Galaxies. II. NGC 3256 Clusters
• HST/STIS spectroscopy of the environment in the starburst core of M82
• Off-center HII regions in power-law density distributions

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