Atacama Large Aperture Submillimeter Telescope
The Atacama Large Aperture Submillimeter Telescope (AtLAST)[1] is an independent project driven by the submillimeter/millimeter astronomical community to build a 50-meter class widefield telescope with over 1 degree field of view. Single dish telescopes with large fields of view can host detector or receiver arrays, making them capable of providing many resolution elements on the sky and surpassing the mapping speed of interferometers such as ALMA[2] by many orders of magnitude, at the expense of lower resolution. In July 2019, a paper[3] was submitted to the US Astro2020 decadal review[4].
Description of the AtLAST project
Observations in the sub-millimeter/millimeter wavelength range reveal the properties of many phases of baryonic matter. Single dish telescopes at these wavelengths are able to recover these often large scale structures, from the Cosmic Microwave Background (CMB) right through to our own Solar System. Large (e.g. 50-m class) single dish telescopes with large fields of view can achieve this with significantly lower confusion limits than current single dish telescopes, and are extremely complementary to powerful sub-mm/mm interferometers such as ALMA that can deliver highly detailed studies but cannot map large-scale structures or perform new large surveys to open up discovery space.
A wide-field photometric and spectroscopic survey of the (sub-)mm sky is the most powerful tool to probe galaxy evolution, from Cosmic Dawn to the present day, local Universe. In the sub-mm, galaxy populations can be mapped in 3D, jointly tracking the co-moving evolution of star formation and their molecular reservoirs across the bulk of cosmic time. Such a telescope is also uniquely capable of capturing, and following, the cycling of warm and cold baryons in and out of galaxies across scales of several arcminutes (100's of kiloparsecs), a process that, despite being crucial to galaxy evolution, has so far remained observationally elusive. It would provide a powerful, ground-based view of the warm/hot, ionized gas in large scale structures such as galaxies, groups, and clusters through observations of the Sunyaev-Zel'dovich effect. More locally, whether through determining how unique our Edgeworth-Kuiper belt is, learning about the variable nature of star formation, or shaping our general understanding of the properties of cool molecular gas, dust, magnetic fields, and hot ionized gas in our Galaxy, there are many unique science drivers for a 50m class single dish telescope capable of spanning this wavelength range.
The Atacama Large Aperture Submillimeter Telescope (AtLAST) aims to fill this wavelength-science gap, bringing at least 1 degree square field of view and covering frequencies from 30 to 950 GHz (roughly 10-0.3 mm wavelength, complementary to the ALMA bands), and allowing high sensitivity observations of the full (sub-)mm sky across multiple spatial scales. We envision AtLAST to be an international partnership operating a facility telescope with an instrument suite providing high-resolution multi-beam spectroscopy, ultra-wideband wide-field spectroscopy for lower spectral resolution mm/sub-mm tomography, and ultra-wide-field multi-chroic polarimetric imaging capabilities. We expect this (dome-less) facility could be built within 10 years, and to last at least 30, based on the lifetimes of current mm and sub-mm telescopes (e.g. IRAM 30m and JCMT).
Building on the legacies of the modern deep and wide Galactic and extragalactic surveys, from radio wavelengths to x-ray, we are entering a golden age of survey science, with missions such as the SKA, SPICA, SPHEREx, eROSITA and LSST coming online in the next 5-15 years. And while ALMA can follow-up many of the discoveries from these facilities in exquisite detail, there is an important gap in survey capabilities at mm/sub-mm/Far-IR wavelengths. For this, a large (50 meter) single dish telescope, with a significant instantaneous field of view, covering a wide wavelength range is required. Current single dish facilities are either too small, which results in high confusion limits, or too far north, resulting in significant mis-matches in observable sky with ALMA. All suffer from having too small a field of view for efficient mapping. Current interferometers, which will have significantly lower confusion limits, suffer from small fields of view and spatial filtering.
To cover this wavelength range requires a high-elevation, dry location, such as the Chajnantor plateau (about 5000 meters above sea level), which has better sub-mm atmospheric conditions than most other sites on Earth, is more accessible than the South Pole, and, having the same sky accessible as ALMA, ensures ALMA follow-up campaigns will be possible for all regions observed with AtLAST.
References
- ↑ "AtLAST [licensed for non-commercial use only] / AtLAST Main Page".
- ↑ "Atacama Large Millimeter Array".
- ↑ Klaassen, Pamela; Mroczkowski, Tony; Bryan, Sean; Groppi, Christopher; Basu, Kaustuv; Cicone, Claudia; Dannerbauer, Helmut; De Breuck, Carlos; Fischer, William J.; Geach, James; Hatziminaoglou, Evanthia; Holland, Wayne; Kawabe, Ryohei; Sehgal, Neelima; Stanke, Thomas; Van Kampen, Eelco (2019). "The Atacama Large Aperture Submillimeter Telescope (AtLAST)". Bulletin of the American Astronomical Society. 51 (7): 58. arXiv:1907.04756. Bibcode:2019BAAS...51g..58K.
- ↑ https://sites.nationalacademies.org/DEPS/astro2020/
Further reading and external links
Publications
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