Abstract
We use data from the Sydney-AAO Multi-Object Integral Field Spectrograph
(SAMI) Galaxy Survey and the Galaxy And Mass Assembly (GAMA) survey to
investigate the spatially-resolved signatures of the environmental quenching of
star formation in galaxies. Using dust-corrected measurements of the
distribution of H$\alpha$ emission we measure the radial profiles of star
formation in a sample of 201 star-forming galaxies covering three orders of
magnitude in stellar mass (M$_*$; $10^8.1$-$10^10.95\, $M$_ødot$) and
in $5^th$ nearest neighbour local environment density ($\Sigma_5$;
$10^-1.3$-$10^2.1\,$Mpc$^-2$). We show that star formation rate gradients
in galaxies are steeper in dense ($łog_10(\Sigma_5/$Mpc$^2)>0.5$)
environments by $0.580.29\, dex\, $r$_e^-1$ in galaxies with stellar
masses in the range $10^10<$M$_*/$M$_ødot<10^11$ and that this
steepening is accompanied by a reduction in the integrated star formation rate.
However, for any given stellar mass or environment density the star-formation
morphology of galaxies shows large scatter. We also measure the degree to which
the star formation is centrally concentrated using the unitless scale-radius
ratio ($r_50,H\alpha/r_50,cont$), which compares the extent of ongoing star
formation to previous star formation. With this metric we find that the
fraction of galaxies with centrally concentrated star formation increases with
environment density, from $54\%$ in low-density environments
($łog_10(\Sigma_5/$Mpc$^2)<0.0$) to $3015\%$ in the highest density
environments ($łog_10(\Sigma_5/$Mpc$^2)>1.0$). These lines of evidence
strongly suggest that with increasing local environment density the star
formation in galaxies is suppressed, and that this starts in their outskirts
such that quenching occurs in an outside-in fashion in dense environments and
is not instantaneous.
Users
Please
log in to take part in the discussion (add own reviews or comments).