Design and Operation of the ATLAS Transient Science Server
Abstract
The Asteroid Terrestrial impact Last Alert System (ATLAS) system consists of two 0.5 m Schmidt telescopes with cameras covering 29 square degrees at plate scale of 1.86 arcsec per pixel. Working in tandem, the telescopes routinely survey the whole sky visible from Hawaii (above $\delta \gt -50^\circ $ ) every two nights, exposing four times per night, typically reaching $o\lt 19$ magnitude per exposure when the moon is illuminated and $c\lt 19.5$ magnitude per exposure in dark skies. Construction is underway of two further units to be sited in Chile and South Africa which will result in an all-sky daily cadence from 2021. Initially designed for detecting potentially hazardous near earth objects, the ATLAS data enable a range of astrophysical time domain science. To extract transients from the data stream requires a computing system to process the data, assimilate detections in time and space and associate them with known astrophysical sources. Here we describe the hardware and software infrastructure to produce a stream of clean, real, astrophysical transients in real time. This involves machine learning and boosted decision tree algorithms to identify extragalactic and Galactic transients. Typically we detect 10-15 supernova candidates per night which we immediately announce publicly. The ATLAS discoveries not only enable rapid follow-up of interesting sources but will provide complete statistical samples within the local volume of 100 Mpc. A simple comparison of the detected supernova rate within 100 Mpc, with no corrections for completeness, is already significantly higher (factor 1.5 to 2) than the current accepted rates.
- Publication:
-
Publications of the Astronomical Society of the Pacific
- Pub Date:
- August 2020
- DOI:
- 10.1088/1538-3873/ab936e
- arXiv:
- arXiv:2003.09052
- Bibcode:
- 2020PASP..132h5002S
- Keywords:
-
- Asteroids;
- Surveys;
- None;
- Variable stars;
- Supernovae;
- 72;
- 1671;
- 1065;
- 1761;
- 1668;
- Astrophysics - Instrumentation and Methods for Astrophysics;
- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 27 pages, 12 figures. Accepted for publication in PASP on 2020 May 15