BlackGEM: the wide-field multi-band optical telescope array

• Main Authors: Groot, Paul J., Bloemen, Steven, Vreeswijk, Paul M., Jonker, Peter G., Pieterse, Danielle, Engels, Arno, Michiels, Jeroen, Bakker, Roy, Hahn, Floris, Raskin, Gert, Morren, Johan, Navarro, Ramon, Elswijk, Eddy, ter Horst, Rik, Schuil, Menno, Kragt, Jan, Lesman, Dirk, de Haan, Menno, Bekema, Marielle, de Haan, Rob, Klein-Wolt, Marc, Blagorodnova, Nadia, Johnston, Cole, Le Poole, Rudolf
• Format: Conference Proceeding
• Language: English
• Published: SPIE 29.08.2022
• ISBN: 9781510653450; 1510653457
• ISSN: 0277-786X
• DOI: 10.1117/12.2630160

The BlackGEM array Phase I consists of three wide field, optical telescopes, located at the ESO La Silla Observatory, Chile. Each telescope is of a modified Dall-Kirkham design, using an 0.6m primary mirror and a 110 Mpix STA1600 CCD to give a 2.7 square degrees field-of-view sampled at 0.56"/pixel. Preliminary commissioning data shows performance on-par with design specifications. Data obtained with the BlackGEM prototype MeerLICHT highlights the capabilities of the design with a 5-sigma limiting magnitude of mAB=22.2 in 300s of integration under dark-sky conditions. Extrapolation to the 1" seeing-conditions expected at La Silla shows that the main goal of BlackGEM to probe down to mAB=23 in 300s can be met. The project suffered a 2-year COVID-19 delay. Commissioning of the array has currently been resumed and science operations are expected to start in Q3/Q4 of 2022. The science programs include the follow-up of gravitational wave alerts from LIGO/Virgo/KAGRA, a six-filter Southern Sky Survey, a Fast Synoptic Survey on selected fields, a Local Universe intra-night monitoring program and a inter-night single-band monitoring for slower transients.