SAMI Galaxy Survey

SAMI Galaxy Survey
Name	SAMI Galaxy Survey
Acronym	SAMI
Affiliation	Australian National University; Anglo-Australian Observatory; European Southern Observatory partners
Location	Siding Spring Observatory, Mount Stromlo Observatory region, New South Wales
Instrument	Hexabundles integral field units; Anglo-Australian Telescope
Wavelength	Optical
Start date	2013
End date	2018

SAMI Galaxy Survey The SAMI Galaxy Survey was a major optical integral field spectroscopic programme conducted with the Anglo-Australian Telescope using fibre-bundle technology to observe thousands of nearby galaxies. It combined multi-object integral field spectroscopy with carefully selected environments from local clusters and field regions to probe galaxy kinematics, star formation, chemical abundance, and environmental effects. The project involved collaborations among institutions such as the Australian National University, the University of Sydney, the University of Oxford, and the Max Planck Society.

Overview

The survey used hexabundle technology developed by teams at the Australian Astronomical Observatory and collaborators affiliated with the University of Oxford and the University of Sydney to enable simultaneous spatially resolved spectroscopy of multiple targets. It targeted a representative sample spanning morphological classes found in catalogues such as the Sloan Digital Sky Survey, the Galaxy And Mass Assembly project, and cluster compilations like the WINGS survey. The collaboration drew expertise from groups associated with the European Southern Observatory, the Max Planck Institute for Astrophysics, and the Harvard–Smithsonian Center for Astrophysics.

Survey Design and Instrumentation

SAMI employed 13 hexabundles feeding the AAOmega spectrograph on the Anglo-Australian Telescope to deliver integral field units across a 1-degree field supplied by the 2dF fibre positioner. The hexabundles were a development involving the Australian National University and teams linked to the University of Sydney and the University of Oxford, leveraging technologies explored at the Cavendish Laboratory and institutions such as the Max Planck Institute for Extraterrestrial Physics. The design traded field multiplex for spatially resolved data, complementing other instruments like the VLT/MUSE at the Very Large Telescope and the CALIFA survey on the Calar Alto Observatory. The spectral setup was informed by experience from the Sloan Digital Sky Survey instrumentation and techniques from the DEEP2 Galaxy Redshift Survey.

Target Selection and Sample

Targets were drawn from parent catalogues including the GAMA survey and the Sloan Digital Sky Survey footprint to ensure robust photometric and spectroscopic ancillary data. The sample included galaxies in environments characterized by cluster studies such as the Virgo Cluster, the Coma Cluster, and groups catalogued in the 2MASS Redshift Survey. Selection prioritized stellar mass ranges established in works by researchers from institutions like the University of Cambridge, the University of California, Berkeley, and the Max Planck Institute for Astronomy. The survey included early-type systems catalogued in the ATLAS3D project and late-type systems comparable to objects in the THINGS survey and the KINGFISH sample to permit cross-comparison.

Observations and Data Reduction

Observations were executed at the Anglo-Australian Telescope site near Coonabarabran, with scheduling coordinated among teams at the Australian Astronomical Observatory and partner institutions including the University of Sydney and the Australian National University. Raw data were reduced using pipelines influenced by software developed for the 2dFGRS and the Sloan Digital Sky Survey, with calibration strategies cognate to those used by the CALIFA survey and the MaNGA survey undertaken by the Sloan Digital Sky Survey IV consortium. Reduction steps addressed fibre-flatfielding, throughput calibration, wavelength calibration tied to standards used at the Royal Observatory, Greenwich, and sky subtraction following methods refined in the DEEP2 Galaxy Redshift Survey and the VVDS survey. Data cubes produced per object enabled analyses comparable to studies from the VLT/MUSE instrument and the SAURON project.

Scientific Goals and Key Results

Primary goals included mapping internal kinematics to test models from groups at the Max Planck Institute for Astrophysics and the Harvard–Smithsonian Center for Astrophysics, measuring spatially resolved star formation and metallicity gradients to inform theories advanced at the Institute of Astronomy, University of Cambridge and the California Institute of Technology, and quantifying environmental quenching processes studied in contexts like the Coma Cluster and the Virgo Cluster. Key results demonstrated links between kinematic morphology and stellar mass highlighted in comparisons to the ATLAS3D and MaNGA findings, revealed prevalence of centrally-concentrated star formation in interactions scenarios discussed by researchers at the University of Oxford and the University of Toronto, and mapped metallicity gradients that constrain gas accretion and feedback models from teams at the Max Planck Institute for Extraterrestrial Physics and the Institute for Astronomy (Edinburgh). The survey enabled studies of galactic winds and outflows akin to work at the Space Telescope Science Institute and informed semi-analytic models developed by groups at the University of Chicago and the Institute of Astronomy, Cambridge.

Data Release and Access

Public data releases were issued to the community with documentation and catalogues maintained by teams at the Australian National University and the Swinburne University of Technology. Data products included reduced datacubes, value-added catalogues cross-matched with the GAMA survey and the Sloan Digital Sky Survey, and higher-level measurements analogous to products from the MaNGA survey and the CALIFA survey. Access mechanisms mirrored practices at the European Southern Observatory and the National Optical Astronomy Observatory, enabling reutilization by research groups at the University of Sydney, the University of Oxford, and the Max Planck Society.

Category:Astronomical surveys Category:Integral field spectroscopy