Galaxy And Mass Assembly (GAMA): Galaxies at the faint end of the Halpha
  luminosity function
  We present an analysis of the properties of the lowest Halpha-luminosity
galaxies (L_Halpha<4x10^32 W; SFR<0.02 Msun/yr) in the Galaxy And Mass Assembly
(GAMA) survey. These galaxies make up the the rise above a Schechter function
in the number density of systems seen at the faint end of the Halpha luminosity
function. Above our flux limit we find that these galaxies are principally
composed of intrinsically low stellar mass systems (median stellar mass
=2.5x10^8 Msun) with only 5/90 having stellar masses M>10^10 Msun. The low SFR
systems are found to exist predominantly in the lowest density environments
(median density ~0.02 galaxy Mpc^-2 with none in environments more dense than
~1.5 galaxy Mpc^-2). Their current specific star formation rates (SSFR; -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
demonstrates that such low-mass, star-forming systems can only remain as
low-mass and forming 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.
