Akiyama, Kazunori;
Alberdi, Antxon;
Alef, Walter;
Algaba, Juan Carlos;
Anantua, Richard;
Asada, Keiichi;
Azulay, Rebecca;
... Yu, Chen-Yu; + view all
(2024)
The persistent shadow of the supermassive black hole of M 87 :
I. Observations, calibration, imaging, and analysis.
Astronomy & Astrophysics
, 681
, Article A79. 10.1051/0004-6361/202347932.
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Abstract
In April 2019, the Event Horizon Telescope (EHT) Collaboration reported the first-ever event-horizon-scale images of a black hole, resolving the central compact radio source in the giant elliptical galaxy M 87. These images reveal a ring with a southerly brightness distribution and a diameter of ∼42 μas, consistent with the predicted size and shape of a shadow produced by the gravitationally lensed emission around a supermassive black hole. These results were obtained as part of the April 2017 EHT observation campaign, using a global very long baseline interferometric radio array operating at a wavelength of 1.3 mm. Here, we present results based on the second EHT observing campaign, taking place in April 2018 with an improved array, wider frequency coverage, and increased bandwidth. In particular, the additional baselines provided by the Greenland telescope improved the coverage of the array. Multiyear EHT observations provide independent snapshots of the horizon-scale emission, allowing us to confirm the persistence, size, and shape of the black hole shadow, and constrain the intrinsic structural variability of the accretion flow. We have confirmed the presence of an asymmetric ring structure, brighter in the southwest, with a median diameter of 43.3−3.1+1.5 μas. The diameter of the 2018 ring is remarkably consistent with the diameter obtained from the previous 2017 observations. On the other hand, the position angle of the brightness asymmetry in 2018 is shifted by about 30° relative to 2017. The perennial persistence of the ring and its diameter robustly support the interpretation that the ring is formed by lensed emission surrounding a Kerr black hole with a mass ∼6.5 × 109 M⊙. The significant change in the ring brightness asymmetry implies a spin axis that is more consistent with the position angle of the large-scale jet.
| Type: | Article |
|---|---|
| Title: | The persistent shadow of the supermassive black hole of M 87 : I. Observations, calibration, imaging, and analysis |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1051/0004-6361/202347932 |
| Publisher version: | https://doi.org/10.1051/0004-6361/202347932 |
| Language: | English |
| Additional information: | © The Authors 2024 Licence Creative CommonsOpen Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This article is published in open access under the Subscribe to Open model. Subscribe to A&A to support open access publication. |
| Keywords: | accretion, accretion disks, black hole physics, gravitation, galaxies: active, galaxies: individual: M 87, galaxies: jets |
| 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-pp.ucl.ac.uk/id/eprint/10204544 |
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