HIZOA J0836-43 is an extreme gas-rich ( M _ { HI } =7.5 \times 10 ^ { 10 } M _ { \sun } ) disk galaxy which lies hidden behind the strongly obscuring Vela region of the Milky Way .
Utilizing observations from the Spitzer Space Telescope , we have found it to be a luminous infrared starburst galaxy with a star formation rate of \sim 21 M _ { \sun } { yr ^ { -1 } } , arising from exceptionally strong molecular PAH emission ( L _ { 7.7 \micron } = 1.50 \times 10 ^ { 9 } L _ { \odot } ) and far-infrared emission from cold dust .
The galaxy exhibits a weak mid-infrared continuum compared to other starforming galaxies and U/LIRGs .
This relative lack of emission from small grains suggests atypical interstellar medium conditions compared to other starbursts .
We do not detect significant [ Ne v ] or [ O iv ] , which implies an absent or very weak AGN .
The galaxy possesses a prominent bulge of evolved stars and a stellar mass of 4.4 ( \pm 1.4 ) \times 10 ^ { 10 } M _ { \sun } .
With its plentiful gas supply and current star formation rate , a doubling of stellar mass would occur on a timescale of \sim 2 Gyr .
Compared to local galaxies , HIZOA J0836-43 appears to be a “ scaled-up ” spiral undergoing inside-out formation , possibly resembling stellar disk building processes at intermediate redshifts .