The BlackGEM Telescope Array. I. Overview
P. Groot, S. Bloemen, P. Vreeswijk, Jan van Roestel, P. G. Jonker, G. Nelemans, M. Klein‐Wolt, R.S. LePoole, D. L. A. Pieterse, M. Rodenhuis, W. Boland, M. Haverkorn, C. Aerts, R. Bakker, Harry Balster, M. E. Bekema, E. Dijkstra, Peter Dolron, Eddy Elswijk, A. van Elteren, Alexander Engels, M. Fokker, M. de Haan, F. Hahn, Rik ter Horst, Dirk Lesman, Jan Kragt, Johan Morren, H. Nillissen, W. Pessemier, Gert Raskin, A. de Rijke, L. H. A. Scheers, M. Schuil, Sjoerd T. Timmer, Larissa Antunes Amaral, Eduardo Arancibia-Rojas, I. Arcavi, N. Blagorodnova, Sumedha Biswas, R. P. Breton, Harry Dawson, Pratika Dayal, S. de Wet, C Duffy, S. M. Faris, Michael Fausnaugh, A. Gal‐Yam, S. Geier, A. Horesh, C. Johnston, G. Katusiime, C. Kelley, Alekzander Kosakowski, Thomas Kupfer, G. Leloudas, A. J. Levan, David Modiano, Orapeleng Mogawana, James Munday, John A. Paice, F. Patat, Ingrid Pelisoli, Gavin Ramsay, P. Ranaivomanana, Roque Ruiz-Carmona, V. Schaffenroth, Simone Scaringi, Fiorenzo Stoppa, R. A. Street, Hugo Tranin, Murat Uzundag, S. Valenti, M Veresvarska, M. Vučković, H. C. I. Wichern, R. A. M. J. Wijers, R. Wijnands, E. Zimmerman
Abstract
Abstract The main science aim of the BlackGEM array is to detect optical counterparts to gravitational wave mergers. Additionally, the array will perform a set of synoptic surveys to detect Local Universe transients and short timescale variability in stars and binaries, as well as a six-filter all-sky survey down to ∼22nd mag. The BlackGEM Phase-I array consists of three optical wide-field unit telescopes. Each unit uses an f /5.5 modified Dall-Kirkham (Harmer-Wynne) design with a triplet corrector lens, and a 65 cm primary mirror, coupled with a 110Mpix CCD detector, that provides an instantaneous field-of-view of 2.7 square degrees, sampled at 0.″564 pixel −1 . The total field-of-view for the array is 8.2 square degrees. Each telescope is equipped with a six-slot filter wheel containing an optimised Sloan set (BG- u , BG- g , BG- r , BG- i , BG- z ) and a wider-band 440–720 nm (BG- q ) filter. Each unit telescope is independent from the others. Cloud-based data processing is done in real time, and includes a transient-detection routine as well as a full-source optimal-photometry module. BlackGEM has been installed at the ESO La Silla observatory as of 2019 October. After a prolonged COVID-19 hiatus, science operations started on 2023 April 1 and will run for five years. Aside from its core scientific program, BlackGEM will give rise to a multitude of additional science cases in multi-colour time-domain astronomy, to the benefit of a variety of topics in astrophysics, such as infant supernovae, luminous red novae, asteroseismology of post-main-sequence objects, (ultracompact) binary stars, and the relation between gravitational wave counterparts and other classes of transients.