IKI GRB-FuN: observations of GRBs with small-aperture telescopes.

Gamma-ray bursts (GRBs) are the most energetic and mysterious events in the Universe, which are observed in all ranges of electromagnetic spectrum. Most valuable results about physics of GRB are obtained by optical observations. GRBs are initially detected in gamma-rays with poor localization accuracy, and an optical counterpart should be found.

Towards a BRICS Optical Transient Network (BRICS-OTN).

This paper is based on a proposal submitted for a BRICS astronomy flagship program, which was presented at the 2019 meeting of the BRICS Astronomy Working Group, held in Rio de Janeiro from 29 September to 2 October 2019. The future prospects for the detection and study of transient phenomena in the Universe heralds a new era in time domain astronomy. The case is presented for a dedicated BRICS-wide flagship program to develop a network of ground-based optical telescopes for an all-sky survey to detect short lived optical transients and to allow follow-up of multi-wavelength and multi-messenger transient objects.

Repetitive patterns in rapid optical variations in the nearby black-hole binary V404 Cygni.

How black holes accrete surrounding matter is a fundamental yet unsolved question in astrophysics. It is generally believed that matter is absorbed into black holes via accretion disks, the state of which depends primarily on the mass-accretion rate. When this rate approaches the critical rate (the Eddington limit), thermal instability is supposed to occur in the inner disk, causing repetitive patterns of large-amplitude X-ray variability (oscillations) on timescales of minutes to hours.