The conceptual design of the 50-meter Atacama Large Aperture Submillimeter Telescope (AtLAST)

• Main Authors: Mroczkowski, Tony, Gallardo, Patricio A, Timpe, Martin, Kiselev, Aleksej, Groh, Manuel, Kaercher, Hans, Reichert, Matthias, Cicone, Claudia, Puddu, Roberto, Dubois-dit-Bonclaude, Pierre, Bok, Daniel, Dahl, Erik, Macintosh, Mike, Dicker, Simon, Viole, Isabelle, Sartori, Sabrina, Venegas, Guillermo Andrés Valenzuela, Zeyringer, Marianne, Niemack, Michael, Poppi, Sergio, Olguin, Rodrigo, Hatziminaoglou, Evanthia, De Breuck, Carlos, Klaassen, Pamela, Montenegro-Montes, Francisco Miguel, Zimmerer, Thomas
• Format: Journal Article
• Language: English
• Published: 28-02-2024
• Subjects: Physics - Astrophysics of Galaxies; Physics - Cosmology and Nongalactic Astrophysics; Physics - High Energy Astrophysical Phenomena; Physics - Instrumentation and Methods for Astrophysics; Physics - Solar and Stellar Astrophysics
• DOI: 10.48550/arxiv.2402.18645

The submillimeter and millimeter ((sub-)mm) sky contains a vast wealth of
information that is both complementary and inaccessible to other wavelengths.
Over half the light we receive is observable at (sub-)mm wavelengths, yet we
have mapped only a small portion of the sky at sufficient spatial resolution
and sensitivity to detect and resolve distant galaxies or star forming cores
within their large-scale environments. For decades the astronomical community
has highlighted the need for a large, high-throughput (sub-)mm ($\lambda\sim
0.35-10$ mm) single dish. The Atacama Large Aperture Submillimeter Telescope
(AtLAST), with its 50-m aperture and $2^\circ$ maximal field of view, aims to
be such a facility. We present here the preliminary design concept for AtLAST,
developed through an EU Horizon 2020-funded design study. Our design approach
begins with a long lineage of (sub-)mm telescopes, relies on calculations and
simulations to realize the optics, and uses finite element analysis to optimize
the designs for the mechanical structure and subsystems. The demanding
technical requirements for AtLAST, set by transformative science goals, have
motivated the design effort to combine novel concepts with lessons learned from
the past experience of previous efforts. The result is an innovative rocking
chair design with six instrument bays, two of which are mounted on Nasmyth
platforms, inside a large receiver cabin. Ultimately, AtLAST aims to achieve a
surface accuracy of $\leq 20~\mu$m root mean square half wavefront error,
corresponding a Ruze efficiency $>50\%$ at 950~GHz. We conclude that
closed-loop metrology of the active primary surface will likely be required to
achieve our surface accuracy goal. In the next phase of the project, we will
prototype and test such metrology on existing platforms, with a goal of
delivering a mature, construction-ready design by the end of this decade.