The Sydney-AAO Multi-object Integral field spectrograph

Abstract

We demonstrate a novel technology that combines the power of the multi-object spectrograph with the spatial multiplex advantage of an integral field spectrograph (IFS). The Sydney-AAO (Australian Astronomical Observatory) Multi-object IFS (SAMI) is a prototype wide-field system at the Anglo-Australian Telescope (AAT) that allows 13 imaging fibre bundles ('hexabundles') to be deployed over a 1-degree diameter field of view. Each hexabundle comprises 61 lightly fused multi-mode fibres with reduced cladding and yields a 75 per cent filling factor. Each fibre core diameter subtends 1.6 arcsec on the sky and each hexabundle has a field of view of 15 arcsec diameter. The fibres are fed to the flexible AAOmega double-beam spectrograph, which can be used at a range of spectral resolutions (R=λ/δλ≈ 1700-13000) over the optical spectrum (3700-9500Å). We present the first spectroscopic results obtained with SAMI for a sample of galaxies at z≈ 0.05. We discuss the prospects of implementing hexabundles at a much higher multiplex over wider fields of view in order to carry out spatially resolved spectroscopic surveys of 104-105 galaxies.