activity
19962025
most citedFirst M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole

1.7k citations · 6.8k across the 60 of their papers we have counts for

collaborators

60 papers

astro-ph.HE2025★ 15 cited

High optical to X-ray polarization ratio reveals Compton scattering in BL Lacertae's jet

Ivan Agudo, Ioannis Liodakis, Jorge Otero-Santos +147

Blazars, supermassive black hole systems (SMBHs) with highly relativistic jets aligned with the line of sight, are the most powerful long-lived emitters of electromagnetic emission…

astro-ph.HE2025★ 8 cited

Looking into the Jet Cone of the Neutrino-Associated Very High Energy Blazar PKS 1424+240

Y. Y. Kovalev, A. B. Pushkarev, J. L. Gomez +7

The acceleration process of massive particles as well as the production of very high energy (VHE) photons and neutrinos remains a fundamental challenge in astrophysics. We investig…

astro-ph.HE2023★ 450 cited

First Sagittarius A* Event Horizon Telescope Results. III: Imaging of the Galactic Center Supermassive Black Hole

The Event Horizon Telescope Collaboration

We present the first event-horizon-scale images and spatiotemporal analysis of Sgr A* taken with the Event Horizon Telescope in 2017 April at a wavelength of 1.3 mm. Imaging of Sgr…

astro-ph.HE2023★ 7 cited

On the need of an ultramassive black hole in OJ 287

Mauri J. Valtonen, Staszek Zola, Achamveedu Gopakumar +25

The highly variable blazar OJ~287 is commonly discussed as an example of a binary black hole system. The 130 year long optical light curve is well explained by a model where the ce…

astro-ph.HE2023★ 7 cited

Observational Implications of OJ 287's Predicted 2022 Disk Impact in the Black Hole Binary Model

Mauri J. Valtonen, Lankeswar Dey, Achamveedu Gopakumar +24

We present a summary of the results of the OJ 287 observational campaign, which was carried out during the 2021/2022 observational season. This season is special in the binary mode…

astro-ph.HE2023

Discovery of X-ray polarization angle rotation in active galaxy Mrk 421

Laura Di Gesu, Herman L. Marshall, Steven R. Ehlert +140

The magnetic field conditions in astrophysical relativistic jets can be probed by multiwavelength polarimetry, which has been recently extended to X-rays. For example, one can trac…