Algaba, JC;
Anczarski, J;
Asada, K;
Baloković, M;
Chandra, S;
Cui, YZ;
Falcone, AD;
... at alia, .; + view all
(2021)
Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign.
The Astrophysical Journal Letters
, 911
(1)
, Article L11. 10.3847/2041-8213/abef71.
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Abstract
In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 10^{9} Mo. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87's spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded.
| Type: | Article |
|---|---|
| Title: | Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.3847/2041-8213/abef71 |
| Publisher version: | https://doi.org/10.3847/2041-8213%2Fabef71 |
| Language: | English |
| Additional information: | © 2021 IOP Publishing. Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence (http://creativecommons.org/licenses/by/3.0). |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10128455 |
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