Multi-wavelength observation of MAXI J1820+070 with MAGIC, VERITAS and H.E.S.S

TL;DR

This study reports multi-wavelength observations of the microquasar MAXI J1820+070 during its 2018 outburst, using gamma-ray telescopes MAGIC, VERITAS, H.E.S.S., and optical detection methods to search for transient emissions.

Contribution

It presents the first coordinated multi-wavelength observational campaign targeting MAXI J1820+070, combining gamma-ray and optical data to search for high-energy transient signals.

Findings

No significant gamma-ray emission detected during observations.

Optical signals captured with high temporal resolution using MAGIC Central Pixel.

Methodology established for future multi-wavelength transient searches.

Abstract

MAXI J1820+070 is a new low-mass microquasar hosting a black hole recently discovered in X-rays by the MAXI instrument. It is the counterpart of ASASSN-18ey, discovered in optical a few days before by ASAS-SN. This source underwent a major outburst in 2018, during which it completed the typical "q-shaped" path in the hardness-intensity diagram. MAGIC, VERITAS and H.E.S.S. gamma-ray telescopes observed the sky position of MAXI J1820+070 for a total of more than 90 hours in 2018. In addition, some observations were carried out using MAGIC Central Pixel - a dedicated central pixel capable of detecting fast optical signals (10 kHz sampling rate, peak sensitivity in the U-band). This contribution presents the methods used to search for transient optical and very high energy gamma-ray emission from MAXI J1820+070, as well as the latest results in these energy ranges.