[论文解读] Atacama Large Aperture Submillimeter Telescope \mbox{(AtLAST)} Science: Probing the Transient and Time-variable Sky

John Orlowski-Scherer, Thomas J. Maccarone+26 more|arXiv (Cornell University)|Apr 19, 2024

Astrophysics and Cosmic Phenomena被引用 6

一句话总结

本论文概述 AtLAST 天文台在亚毫米波瞬变与时间变量科学方面的潜力，详细论述科学案例、观测能力与 survey 策略，以最大化对快速演变现象的发现与跟进。

ABSTRACT

The study of transient and variable events, including novae, active galactic nuclei, and black hole binaries, has historically been a fruitful path for elucidating the evolutionary mechanisms of our universe. The study of such events in the millimeter and submillimeter is, however, still in its infancy. Submillimeter observations probe a variety of materials, such as optically thick dust, which are hard to study in other wavelengths. Submillimeter observations are sensitive to a number of emission mechanisms, from the aforementioned cold dust, to hot free-free emission, and synchrotron emission from energetic particles. Study of these phenomena has been hampered by a lack of prompt, high sensitivity submillimeter follow-up, as well as by a lack of high-sky-coverage submillimeter surveys. In this paper, we describe how the proposed Atacama Large Aperture Submillimeter Telescope (AtLAST) could fill in these gaps in our understanding of the transient universe. We discuss a number of science cases that would benefit from AtLAST observations, and detail how AtLAST is uniquely suited to contributing to them. In particular, AtLAST's large field of view will enable serendipitous detections of transient events, while its anticipated ability to get on source quickly and observe simultaneously in multiple bands make it also ideally suited for transient follow-up. We make theoretical predictions for the instrumental and observatory properties required to significantly contribute to these science cases, and compare them to the projected AtLAST capabilities. Finally, we consider the unique ways in which transient science cases constrain the observational strategies of AtLAST, and make prescriptions for how AtLAST should observe in order to maximize its transient science output without impinging on other science cases.

研究动机与目标

• Motivate a wide-field, high-sensitivity single-dish submillimeter facility to study transient and time-variable phenomena.
• Define observational capabilities and constraints needed to maximize transient science output without compromising other goals.
• Describe how AtLAST complements existing facilities and enables serendipitous discoveries and rapid follow-up across multiple bands.
• Highlight solar system, Galactic, and extragalactic science cases that benefit from AtLAST’s FoV, sensitivity, and multi-chroic capabilities.

提出的方法

• Argue for a 50 m single-dish telescope with a large instantaneous field of view (>1 deg^2).
• Propose simultaneous multi-band (multi-chroic) observing in the 90–850 GHz regime.
• Assess survey strategies including wide-area mapping, targeted follow-up, and serendipitous discovery pipelines.
• Present sensitivity benchmarks and cadence requirements to enable detection and characterization of transients in the submillimeter.
• Reference existing and planned facilities to motivate AtLAST’s niche and synergy (e.g., ACT, SPT, JCMT/SCUBA-2, ALMA, SO, CCAT).
• Provide a table of nominal atmospheric bands and their expected sensitivities to guide instrument design (Table 1 in the paper).

Figure 1: AtLAST projected 1 hour cumulative observations of (4866) Badillo alongside WISE (open circle) data points. The red, green, and blue data points represent projected AtLAST observations reduced by 5, 25, and $35\%$ with respect to best fit IR line (solid blue line), which in turn correspond

实验结果

研究问题

• RQ1 What capabilities must AtLAST have to maximize discovery and characterization of transient and time-variable events in the submillimeter?
• RQ2 How can AtLAST’s wide field of view, multi-band reach, and rapid response enable serendipitous detections and effective follow-up of transients detected at other wavelengths or by multi-messenger alerts?
• RQ3 What are the optimal observing strategies (surveys, targeted follow-up, cadence) to study solar system, Galactic, and extragalactic time-domain phenomena with AtLAST?
• RQ4 What are the limitations of current facilities in transient submillimeter science, and how does AtLAST address these gaps?
• RQ5 How can AtLAST observations constrain models of asteroid regolith, TNOs, protostellar accretion variability, and other time-variable submillimeter phenomena?

主要发现

参考频率	带边界	灵敏度 (μJy beam^-1 h^-1/2)	波段 1 (GHz)	波段 2 (GHz)	灵敏度 (μJy beam^-1 h^-1/2)
42.0	30-54	6.60	91.5	66-117	6.46
91.5	66-117	6.46	151.0	120-182	7.14
151.0	120-182	7.14	217.5	183-252	9.22
217.5	183-252	9.22	288.5	252-325	11.91
288.5	252-325	11.91	350.0	325-375	23.59
350.0	325-375	23.59	403.0	384-422	39.98
403.0	384-422	39.98	654.0	595-713	98.86
654.0	595-713	98.86	845.5	768-905	162.51

• AtLAST’s large instantaneous field of view (>1 deg^2) and 50 m aperture enable rapid wide-area surveys with high sensitivity, expanding transient discovery potential beyond current millimeter facilities.
• Multi-band, simultaneous observing reduces the need for frequent reconfiguration and enables probing spectral energy distributions during rapid variability events.
• Serendipitous detections and rapid follow-up of transients, including multi-messenger sources, become feasible due to fast slewing, high sensitivity, and polarization capabilities.
• The paper provides projected sensitivities and band definitions (Table 1) that guide design choices and observing strategies to optimize transient science outputs.
• Asteroid and TNO studies in the submillimeter become practical with AtLAST, enabling large catalogs and compositional insights not achievable with current facilities.
• The study emphasizes the need for real-time alert pipelines and homogeneous data products to maximize the scientific return of transient submillimeter observations.

Figure 2: A multiwavelength campaign on the black hole X-ray binary MAXI J1820+070 in outburst, from Tetarenko et al. 2021 . The emission from infrared through radio is thought to be synchrotron from a relativistic jet. The increased smoothness of the light curves as a function of increasing wavelen