This talk is being given on behalf of the EHT Multiwavelength WG, and the EHT, Fermi-LAT, Magic, VERITAS, HESS and EAVN collaborations.
In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the black hole at the center of the M 87 galaxy. In order to support the physical interpretation and modeling of this exceptional data, the EHT Collaboration also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. In this talk, I will highlight the key results of this campaign obtained with with ground- and space-based facilities from radio all the way up to the TeV range. I will focus on the results of applying two simple, single-zone models assuming isotropic electron distribution function and magnetic fields; the main conclusion is that a structured jet is necessary to simultaneously explain all of M87’s observational properties. Our models allow us to rule out a scenario in which the γ-ray emission is produced via inverse Compton emission in the same region that produces the EHT mm-band emission, and further conclude that such γ-rays can only be produced in the inner jets (in-wards of HST-1) if there are strongly particle-dominated regions