Cosmic gamma-ray bursts (GRBs) and soft gamma-ray repeaters (SGRs) are the brightest sources of high-energy electromagnetic radiation. For many years, GRB and SGR studies have been among the major basic research areas at the Ioffe Institute. The physical processes that power immense luminosity of the cosmic gamma-ray sources are of utmost interest since they enable exploring physical phenomena in the vicinities of stellar-mass black holes and neutron stars, whose magnetic fields are probably larger than the critical value for vacuum polarization, i.e., under the conditions inaccessible for terrestrial laboratories. Owing to high luminosity, GRBs may be detected out to the edge of the visible Universe thus enabling one to study how first stars have emerged and probe properties of matter along the entire line of sight to the sources. We briefly review the results of modern multi-wavelength studies of cosmic gamma-ray bursts and soft gamma-repeaters. The history of development of, main accomplishments in, and prospects for studies of GRBs and SGRs, a vibrant area of basic astrophysical research at the Ioffe Institute, are presented. We describe in detail the results obtained with several generations of KONUS detectors that have been designed and manufactured at the Ioffe Institute. Observational data obtained by space-based instruments are effectively complemented by theoretical modeling of astrophysical processes that exhibit extreme energy release. We also discuss prospects for the GRB and SGR studies including future experiments scheduled at Ioffe Institute.
Keywords: cosmic gamma-ray bursts, soft gamma-repeaters, burst light curves, burst energy spectra PACS:95.55.Ka, 97.80.Gm, 98.70.Rz (all) DOI:10.3367/UFNe.2018.11.038488 URL: https://ufn.ru/en/articles/2019/8/b/ Citation: Aptekar R L, Bykov A M, Golenetskii S V, Frederiks D D, Svinkin D S, Ulanov M V, Tsvetkova A E, Kozlova A V, Lysenko A L "Cosmic gamma-ray bursts and soft gamma-repeaters — observations and modeling of extreme astrophysical phenomena (100th anniversary of the Ioffe Institute)" Phys. Usp.62 739–753 (2019)