News

First Light for Unique Astrophotonic Instrument


22 July 2011

In a world first, astronomers from the University of Sydney's School of Physics, together with collaborators at the Australian Astronomical Observatory (AAO) have commissioned a new instrument on the Anglo-Australian Telescope (AAT), making use of new and novel astrophotonic technology.


Sydney-AAO Multi-object IFU (SAMI) is a multiplexed integral field unit (IFU) astronomical instrument based on hexabundle technology and feeds the AAOmega spectrograph. SAMI has been built in collaboration with the Astrophotonics Group, Sydney Institute for Astronomy (SIfA) in the School of Physics, and the AAO for the AAT.


Hexabundles are a new fibre-imaging device developed by the Astrophotonics Group and consist of 105-micron core multimode fibres with only five micron cladding, which are lightly fused over a short distance to form an imaging bundle with high fill-factor. The instrument consists of thirteen hexabundles and so can observe thirteen astronomical targets at once.


A velocity map derived from one of the first galaxy targets observed with SAMI.  The colour corresponds to relative velocity within the galaxy in units of km/s, with blue coming towards us and red away from us.  Each circle represents the location on the sky of a single core within a Hexabundle.  This galaxy shows the signature of a rotating disk.
A velocity map derived from one of the first galaxy targets observed with SAMI. The colour corresponds to relative velocity within the galaxy in units of km/s, with blue coming towards us and red away from us. Each circle represents the location on the sky of a single core within a Hexabundle. This galaxy shows the signature of a rotating disk.

The spatially resolved spectroscopy enabled by the SAMI instrument will allow astronomers to measure a wide range of key physical parameters, such as dynamical mass, angular momentum, the location of star formation and many others. It will also remove the biases inherent in single fibre studies of the same kind. The hexabundle technology has been crucial in enabling easy construction of a system which can target more than one object at once in this spatially resolved mode.


The SAMI team, led by Scott Croom (USyd.) and Jon Lawrence (AAO) who installed the instrument, aligned and tested it on the sky over a four-night run from 1 to 4 July 2011 proving it to be a huge success.


The instrument was able to acquire data on both stars and galaxies, with preliminary analysis of the galaxies clearly demonstrating the ability of SAMI to measure galaxy dynamics. These results bode well for the prospects of carrying out major new surveys with SAMI, potentially targeting thousands of galaxies with spatially resolved spectroscopy.


School of Physics SAMI team members are: Professor Joss Bland-Hawthorn, Dr Julia Bryant, Assoc. Professor Scott Croom, Dr Lisa Fogarty, Professor Geraint Lewis and Mr Sam Richards.



Contact: Assoc. Professor Scott Croom

Phone: 02 9036 5311

Email: 41613b1627072608210a00322d2530055e300a5c17520902595737