Optical and X-ray timing analysis of the 2018–2020 outburst and rebrightening of the black hole transient MAXI J1820+070
Journal: Astronomy and Astrophysics
Year: 2025

We report the results of a comprehensive analysis of the multi-wavelength (in optical and X-rays) and multi-timescale (from months to tenths of a second) variability of the 2018–2020 outburst of the black hole transient MAXI J1820+070. A detailed analysis of the optical photometry revealed a periodicity that evolves over time during the first outburst episode and stabilises at a frequency of 1.4517(1) 1/d (∼0.5% longer than the orbital period). This super-orbital modulation is also seen in the X