Detection and characterisation of submm transient sources with a large single-dish telescope

TL;DR

The paper argues for a large, single-dish submillimeter telescope (approximately $50\ \,\mathrm{m}$) to enable sensitive, wide-field, multi-epoch surveys that detect and characterize submillimeter transients. It catalogs the expected Galactic and extragalactic transient classes and proposes two detection pathways: autonomous wide-field surveys and rapid follow-up of events from other facilities or multi-wavelength triggers, including archival cross-checks. Technical requirements are outlined, highlighting the need for $30$--$950$ GHz coverage, a large $2^\\circ$ FoV, and fast mapping at high-altitude sites, with AtLAST identified as a particularly well-suited concept. The work concludes that such a facility would significantly increase transient yields, improve localisation and spectral characterization, and complement existing facilities like ALMA and SO and infrared programs like PRIMA.

Abstract

The exploration of the time-variable astronomical sky at submm wavelengths is rapidly becoming more feasible with large sky surveys by Cosmic Microwave Background telescopes with tens of thousands of detectors. Observations with the Atacama Cosmology Telescope and South Pole Telescope have already detected some transients, and Simons Observatory and CCAT are expected to detect many more in the near future. Follow-up observations to characterise these transients, and surveying to uncovering fainter populations, will need high sensitivity and large fields of view at submm wavelengths, which could be provided by large single dish telescopes such as AtLAST.

Figures (2)

• Figure 1: Cartoon depiction of a transient event going off with a clock superimposed to indicate time. Image from https://atlast-telescope.org/science/ courtesy L. Di Mascolo.
• Figure 2: Light curves of various extragalactic transients (SNe, GRBs, TDEs and FBOTs) at millimetre wavelengths, from Eftekhari2022.