Hector: a new massively multiplexed IFU instrument for the Anglo-Australian Telescope

Abstract

Hector [1,2,3] will be the new massively-multiplexed integral field spectroscopy (IFS) instrument for the Anglo-Australian Telescope (AAT) in Australia and the next main dark-time instrument for the observatory. Based on the success of the SAMI instrument, which is undertaking a 3400-galaxy survey, the integral field unit (IFU) imaging fibre bundle (hexabundle) technology under-pinning SAMI is being improved to a new innovative design for Hector. The distribution of hexabundle angular sizes is matched to the galaxy survey properties in order to image 90% of galaxies out to 2 effective radii. 50-100 of these IFU imaging bundles will be positioned by 'starbug' robots across a new 3-degree field corrector top end to be purpose-built for the AAT. Many thousand fibres will then be fed into new replicable spectrographs. Fundamentally new science will be achieved compared to existing instruments due to Hector's wider field of view (3 degrees), high positioning efficiency using starbugs, higher spectroscopic resolution (R=3000-5500 from 3727-7761Å, with a possible redder extension later) and large IFUs (up to 30 arcsec diameter with 61-217 fibre cores). A 100,000 galaxy IFS survey with Hector will decrypt how the accretion and merger history and large-scale environment made every galaxy different in its morphology and star formation history. The high resolution, particularly in the blue, will make Hector the only instrument to be able to measure higher-order kinematics for galaxies down to much lower velocity dispersion than in current large IFS galaxy surveys, opening up a wealth of new nearby galaxy science.The overarching science goal is to understand the physical basis for the diversity of galaxy properties in the local Universe. Substantial steps forward have been possible with smaller surveys such as SAMI, which have sufficient sample sizes to study the properties of galaxies as a function of their mass and local environment, but the diversity of galaxies is driven by more than just these two parameters. The accretion and/or merger history of a galaxy is fundamental to its morphology and star formation history, but to date it has been hard or impossible to capture the diversity of accretion histories observationally. The broader large-scale environment is also known to be important in determining a galaxy's structure via tidal torques. Only with Hector targeting 100,000 galaxies can we hope to probe the detailed physics of galaxy formation in these two extra dimensions of accretion history and large-scale environment. Specifically, the integral field data from Hector can provide specific angular momentum, higher order velocity moments, mis-alignments between gas and stars as well as measure dynamical disturbance. All of these tracers provide a view into accretion and merger history, which when combined with the unprecedented sample size of Hector will allow us to connect a galaxy's specific history to its current state. By connecting these properties to the network of large-scale structure we will be able to show h...

Alignment between Filaments and Galaxy Spins from the MaNGA Integral-field Survey

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The SAMI Galaxy Survey: mass–kinematics scaling relations

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A Review of Recent Observations of Galactic Winds Driven by Star Formation

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