New 50-m-class single-dish telescope: Large Submillimeter Telescope (LST)

Abstract

We report on a plan to construct a 50-m-class single-dish telescope, the Large Submillimeter Telescope (LST). The conceptual design and key science behind the LST are presented, together with its tentative specifications. This telescope is optimized for wide-area imaging and spectroscopic surveys in the 70-420 GHz frequency range, which spans the main atmospheric windows at millimeter and submillimeter wavelengths for good observation sites such as the Atacama Large Millimeter/submillimeter Array (ALMA) site in Chile. We also target observations at higher frequencies of up to 1 THz, using an inner high-precision surface. Active surface control is required in order to correct gravitational and thermal deformations of the surface, and will be useful for correction of the wind-load deformation. The LST will facilitate new discovery spaces such as wide-field imaging with both continuum and spectral lines, along with new developments for time-domain science. Through exploitation of its synergy with ALMA and other telescopes, the LST will contribute to research on a wide range of topics in the fields of astronomy and astrophysics, e.g., astrochemistry, star formation in our Galaxy and galaxies, the evolution of galaxy clusters via the Sunyaev-Zel'dovich (SZ) effect, the search for transients such as γ-ray burst reverse shocks produced during the epoch of re-ionization, electromagnetic follow up of detected gravitational wave sources, and examination of general relativity in the vicinity of super massive black holes via submillimeter very-long-baseline interferometry (VLBI).

Wideband on-chip terahertz spectrometer based on a superconducting filterbank

“…Furthermore, the compactness of the spectrometer chip allows small spectrometer units that can be combined into a focal plane array of spectrometer pixels-what is often referred to as a hyperspectral imager or imaging spectrometer. Indeed, the on-chip spectrometer is regarded as the most viable path towards a ∼100 pixel multi-object spectrometer, which is expected to substantially improve the galaxy-surveying capabilities of existing ground-based observatories for terahertz astronomy, 48,49 and enable future satellite missions for climatology and meteorology applications. 2…”

A joint ALMA–Bolocam–Planck SZ study of the pressure distribution in RX J1347.5−1145

“…In the longer term, a much larger field of view ( 1degree), high spatial and spectral resolution submillimetre facility such as the 50-meter Atacama Large Aperture Submillimeter Telescope 4 (see e.g. Bertoldi 2018, Mroczkowski et al 2019a or the Large Submillimeter Telescope (Kawabe et al 2016) would provide imaging of not only clusters, but also much larger areas of the sky, down to the sensitivities required to measure systems in the group and galaxy mass regime as well as the surrounding intergalactic filamentary structure.…”

The Atacama large aperture submillimeter telescope (AtLAST) concept

“…Our baseline design is for a 50-m on-axis Cassegrain-Nasmyth hybrid configuration (see Figure 1). While several off-axis designs for smaller (1-10 m) telescopes exist and provide wide fields and unblocked apertures, we feel the challenge of delivering a sufficiently rigid structure that can achieve fast enough scan speeds to modulate the atmosphere sufficiently rapidly ( 0.2 Hz, or 1deg s −1 ) is best met by building on the experience of the 50-m LMT design: There are significant similarities to the 50-m LMT, 45 and indeed the 50-meter Large Submillimeter Telescope (LST) concept, 46 in the left panel of Figure 1. Aside from a higher and drier site and access to more of the Southern sky, some key advantages to AtLAST are a large, 12-m secondary mirror enabling ∼ 500× the FoV of the LMT, and an improved receiver cabin to host larger and more instruments from the start.…”