Broadband multi-wavelength properties of M87 during the 2017 Event Horizon Telescope campaign

Algaba, J. C. and Anczarski, J. and Asada, K. and Balokovic, M. and Chandra, S. and Cui, Y-Z and Falcone, A. D. and Giroletti, M. and Goddi, C. and Hada, K. and Haggard, D. and Jorstad, S. and Kaur, A. and Kawashima, T. and Keating, G. and Kim, J-Y and Kino, M. and Komossa, S. and Kravchenko, E. and Krichbaum, T. P. and Lee, S-S and Lu, R-S and Lucchini, M. and Markoff, S. and Neilsen, J. and Nowak, M. A. and Park, J. and Principe, G. and Ramakrishnan, V and Reynolds, M. T. and Sasada, M. and Savchenko, S. S. and Williamson, K. E. (2021) Broadband multi-wavelength properties of M87 during the 2017 Event Horizon Telescope campaign. The Astrophysical Journal Letters, 911 (1). ISSN 2041-8205, DOI

Full text not available from this repository.


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 similar to 6.5 x 10(9) M-circle dot. 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 gamma-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the gamma-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.

Item Type: Article
Funders: Malaysian Fundamental Research Grant Scheme (FRGS) (Grant No: FRGS/1/2019/STG02/UM/02/6)
Uncontrolled Keywords: Active galactic nuclei; Radio cores; Low-luminosity active galactic nuclei; High energy astrophysics; Astrophysical black holes; Accretion
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Faculty of Science > Department of Physics
Depositing User: Ms Zaharah Ramly
Date Deposited: 04 Oct 2023 02:34
Last Modified: 04 Oct 2023 02:34

Actions (login required)

View Item View Item