SAMI is the Sydney-AAO Multi-object Integral-field unit that feeds the AAOmega spectrograph. SAMI provides 13 fibre-based IFUs called 'hexabundles' (see Bryant et al. 2014, MNRAS, 438, 869), each with a field of view of 15 arcseconds sampled with 61 1.6-arcsecond fibres. These IFUs can be deployed by plug plate anywhere within a 1-degree field of view using the AAT's Prime Focus Camera top end. These are fed by fibre, along with 26 pluggable sky fibres, to the AAOmega spectrograph, providing configurable wavelength range and resolution across the optical spectrum.
The double beam spectrograph has interchangeable gratings that can be selected by the user. A set of low, medium, and high resolution gratings provide R ~ 1,000, R ~ 5,000 or R ~ 10,000 across the wavelength range 330 nm to 900 nm. Each arm can be independently configured. The two arms are separated by a dichroic mirror with either a 570nm or 670nm cut. Full spectral coverage is possible in a single exposure with the low-resolution gratings.
SAMI was originally developed for the SAMI galaxy survey, and details of the upgrade of the instrument including throughputs can be found in the SAMI survey paper (Bryant et al., 2015, MNRAS 447, 2857).
SAMI is being offered as a common user instrument for the first time in semester 16A.