[FeII] as a tracer of supernova rate in nearby starburst galaxies

Sterrewacht Leiden, Universiteit Leiden, PO Box 9513, 2300 RA Leiden, The Netherlands
e-mail: rosenberg@strw.leidenuniv.nl

Received: 4 January 2012
Accepted: 9 February 2012

Abstract

Context. Supernovae play an integral role in the feedback of processed material into the ISM of galaxies making them responsible for much of the chemical enrichment of the universe. The rate of supernovae can also reveal star formation histories. These rates are usually measured through the nonthermal radio continuum luminosity; however, a correlation between near-infrared [FeII] emission and supernova remnants has also been noted.

Aims. We aim to find a quantitative relationship between the [FeII] at 1.26 μm ([FeII]_1.26) luminosity and the supernova rate in a sample of 11 nearby starburst galaxy centers.

Methods. We performed a pixel-pixel analysis of this correlation on SINFONI data cubes. Using Brγ equivalent width and luminosity as the only observational inputs into the Starburst 99 model, we derived the supernova rate at each pixel and have thus created maps of supernova rates. We then compared these morphologically and quantitatively to the [FeII]_1.26 luminosity.

Results. We have found that a strong linear and morphological correlation exists between supernova rate and [FeII]_1.26 on a pixel-to-pixel basis. This relation is valid for normal star-forming galaxies but breaks down for extreme ultraluminous galaxies.

Conclusions. The supernova rates derived from the Starburst 99 model are in good agreement with the radio derived supernova rates, which underlines the strength of using [FeII] emission as a tracer of supernova rate. With the strong correlation found in this sample of galaxies, we conclude that [FeII]_1.26 emission can generally be used to derive accurate supernova rates on either a pixel-pixel or integrated galactic basis.