Galaxy and Mass Assembly (GAMA): Galaxies at the faint end of the H alpha luminosity function

Sarah Brough, Andrew Hopkins, Robert Sharp, Madusha Gunawardhana, Dinuka Wijesinghe, A Robotham, Simon Driver, Ivan Baldry, Steven Bamford, J Liske, J Loveday, Peder Norberg, John Peacock, Joss Bland-Hawthorn, Michael Brown, Ewan Cameron, Scott Croom, C Frenk, C Foster, D HillDavid Jones, L Kelvin, K Kuijken, Robert Nichol, H Parkinson, Kevin Pimbblet, Cristina Popescu, Matthew Prescott, W Sutherland, Edward Taylor, D Thomas, R Tuffs, E van Kampen

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    29 Citations (Scopus)


    We present an analysis of the properties of the lowest HI?-luminosity galaxies (LHI?a?? 4 ?? 1032 W; SFR <0.02 MaS?yr-1, with SFR denoting the star formation rate) in the Galaxy And Mass Assembly survey. These galaxies make up the rise above a Schechter function in the number density of systems seen at the faint end of the HI? luminosity function. Above our flux limit, we find that these galaxies are principally composed of intrinsically low stellar mass systems (median stellar mass = 2.5 ?? 108MaS?) with only 5/90 having stellar masses M > 1010MaS?. The low-SFR systems are found to exist predominantly in the lowest-density environments (median density a??0.02galaxyMpc-2) with none in environments more dense than a??1.5galaxyMpc-2. Their current specific SFRs (SSFRs; -8.5 <log[SSFR (yr -1)] <-12) are consistent with their having had a variety of star formation histories. The low-density environments of these galaxies demonstrate that such low-mass, star-forming systems can only remain as low mass and form stars if they reside sufficiently far from other galaxies to avoid being accreted, dispersed through tidal effects or having their gas reservoirs rendered ineffective through external processes.
    Original languageEnglish
    Pages (from-to)1236 - 1243
    Number of pages8
    JournalMonthly Notices of the Royal Astronomical Society
    Issue number2
    Publication statusPublished - 2011

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