Galaxy And Mass Assembly (GAMA): bivariate functions of Halpha star-forming galaxies

Madusha Gunawardhana, Andrew Mark Hopkins, Edward N Taylor, Jonathan Bland-Hawthorn, Peder Norberg, Ivan K Baldry, J Loveday, Matthew S Owers, Stephen M Wilkins, Matthew Malcolm Colless, Michael James Isles Brown, Simon P Driver, Mehmet Alpaslan, Sarah Brough, Michelle E Cluver, Scott Martin Croom, Lee S Kelvin, Maritza Arlene Lara-Lopez, J Liske, Angel R Lopez-SanchezA S G Robotham

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We present bivariate luminosity and stellar mass functions of Ha star-forming galaxies drawn from the Galaxy And Mass Assembly (GAMA) survey. While optically deep spectroscopic observations of GAMA over a wide sky area enable the detection of a large number of 0.001 <SFRHa (M yr-1) <100 galaxies, the requirement for an Ha detection in targets selected from an r-band magnitude-limited survey leads to an incompleteness due to missing optically faint star-forming galaxies. Using z <0.1 bivariate distributions as a reference we model the higher-z distributions, thereby approximating a correction for the missing optically faint star-forming galaxies to the local star formation rate (SFR) andMdensities. Furthermore, we obtain the r-band luminosity functions (LFs) and stellar mass functions of Ha star-forming galaxies from the bivariate LFs.As our sample is selected on the basis of detectedHa emission, a direct tracer of ongoing star formation, this sample represents a true star-forming galaxy sample, and is drawn from both photometrically classified blue and red subpopulations, though mostly from the blue population. On average 20-30 per cent of red galaxies at all stellar masses are star forming, implying that these galaxies may be dusty star-forming systems.
Original languageEnglish
Pages (from-to)875-901
Number of pages27
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
Publication statusPublished - 2015

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