The SED of the nearby HI-massive LIRG HIZOA J0836-43: from the NIR to the radio domain

TL;DR

This study investigates the properties of the nearby HI-massive galaxy HIZOA J0836-43 across multiple wavelengths, revealing its active star formation, large gas reservoir, and similarities to high-redshift galaxies, despite its local universe location.

Contribution

It provides a comprehensive multi-wavelength analysis of a rare, HI-massive galaxy, highlighting its unique star formation characteristics and evolutionary implications.

Findings

Active, inside-out stellar disk-building observed.

Galaxy exhibits high gas content fueling star formation.

Characteristics resemble scaled-up local spirals, akin to high-redshift systems.

Abstract

HIZOA J0836-43is one of the most HI-massive galaxies in the local (z<0.1) Universe. Not only are such galaxies extremely rare, but this "coelacanth" galaxy exhibits characteristics -- in particular its active, inside-out stellar disk-building -- that appear more typical of past (z ~ 1) star formation, when large gas fractions were more common. Unlike most local giant HI galaxies, it is actively star forming. Moreover, the strong infrared emission is not induced by a merger event or AGN, as is commonly found in other local LIRGs. The galaxy is suggestive of a scaled-up version of local spiral galaxies; its extended star formation activity likely being fueled by its large gas reservoir and, as such, can aid our understanding of star formation in systems expected to dominate at higher redshifts. The multi-wavelength imaging and spectroscopic observations that have led to these deductions will be presented. These include NIR (J H K) and MIR (Spitzer; 3-24micron) imaging and photometry, MIR spectroscopy, ATCA HI-interferometry and Mopra CO line emission observations. But no optical data, as the galaxy is heavily obscured due to its location in Vela behind the Milky Way.