H.E.S.S. Follow-up Observations of Binary Black Hole Coalescence Events during the Second and Third Gravitational-wave Observing Runs of Advanced LIGO and Advanced Virgo
H. Abdalla, F. Aharonian, F. Ait Benkhali, E. O. Angüner, Halim Ashkar, Michael Backes, Vardan Baghmanyan, V. Barbosa Martins, R. Batzofin, Y. Becherini, D. Berge, K. Bernlöhr, Baiyang Bi, M. Böttcher, C. Boisson, J. Bolmont, Mathieu de Bony de Lavergne, Robert Brose, F. Brun, T. Bulik, T. Bylund, F. Cangemi, Sami Caroff, S. Casanova, T. Chand, A. Chen, Garret Cotter, J. Damascene Mbarubucyeye, J. Devin, A. Djannati-Ataı̈, K. Egberts, J.-P. Ernenwein, S. Fegan, A. Fiaßon, Gaëtan Fichet de Clairfontaine, G. Fontaine, S. Funk, S. Gabici, G. Giavitto, Luca Giunti, D. Glawion, J. F. Glicenstein, M.-H. Grondin, J. A. Hinton, M. Hörbe, Werner Hofmann, T. L. Holch, M. Holler, Zhi-Qiu Huang, David Miles Huber, M. Jamrozy, F. Jankowsky, I. Jung-Richardt, E. Kasai, K. Katarzyński, U. Katz, B. Khélifi, Nu. Komin, Ruslan Konno, K. Kosack, D. Kostunin, A. Kundu, G. Lamanna, S. Le Stum, A. Lemière, M. Lemoine‐Goumard, J.-P. Lenain, Fabian Leuschner, T. Lohse, Anna Luashvili, I. Lypova, Jonathan Mackey, Jhilik Majumdar, D. Malyshev, V. Marandon, ¶. Marchegiani, G. Martí-Devesa, R. Marx, G. Maurin, P. J. Meintjes, Alison Mitchell, L. Mohrmann, Alessandro Montanari, E. Moulin, J. M. Muller, T. Murach, M. de Naurois, A. Nayerhoda, J. Niemiec, A. Priyana Noel, P. T. O’Brien, S. Ohm, Laura Olivera-Nieto, E. de Oña Wilhelmi, M. Ostrowski, M. Panter, R. D. Parsons, Giada Peron, V. Poireau, Д. А. Прохоров
Abstract
Abstract We report on the observations of four well-localized binary black hole (BBH) mergers by the High Energy Stereoscopic System (H.E.S.S.) during the second and third observing runs of Advanced LIGO and Advanced Virgo, O2 and O3. H.E.S.S. can observe 20 deg 2 of the sky at a time and follows up gravitational-wave (GW) events by “tiling” localization regions to maximize the covered localization probability. During O2 and O3, H.E.S.S. observed large portions of the localization regions, between 35% and 75%, for four BBH mergers (GW170814, GW190512_180714, GW190728_064510, and S200224ca). For these four GW events, we find no significant signal from a pointlike source in any of the observations, and we set upper limits on the very high energy (>100 GeV) γ -ray emission. The 1–10 TeV isotropic luminosity of these GW events is below 10 45 erg s −1 at the times of the H.E.S.S. observations, around the level of the low-luminosity GRB 190829A. Assuming no changes are made to how follow-up observations are conducted, H.E.S.S. can expect to observe over 60 GW events per year in the fourth GW observing run, O4, of which eight would be observable with minimal latency.