Projects per year
Abstract
We present the first Event Horizon Telescope (EHT) images of M87, using observations from April 2017 at 1.3 mm wavelength. These images show a prominent ring with a diameter of ∼40 μas, consistent with the size and shape of the lensed photon orbit encircling the "shadow" of a supermassive black hole. The ring is persistent across four observing nights and shows enhanced brightness in the south. To assess the reliability of these results, we implemented a two-stage imaging procedure. In the first stage, four teams, each blind to the others' work, produced images of M87 using both an established method (CLEAN) and a newer technique (regularized maximum likelihood). This stage allowed us to avoid shared human bias and to assess common features among independent reconstructions. In the second stage, we reconstructed synthetic data from a large survey of imaging parameters and then compared the results with the corresponding ground truth images. This stage allowed us to select parameters objectively to use when reconstructing images of M87. Across all tests in both stages, the ring diameter and asymmetry remained stable, insensitive to the choice of imaging technique. We describe the EHT imaging procedures, the primary image features in M87, and the dependence of these features on imaging assumptions.
Original language | English |
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Article number | 4 |
Number of pages | 52 |
Journal | Astrophysical Journal Letters |
Volume | 875 |
Issue number | 1 |
DOIs | |
Publication status | Published - 10 Apr 2019 |
MoE publication type | A1 Journal article-refereed |
Keywords
- black hole physics
- galaxies: individual (M87)
- galaxies: jets
- techniques: high angular resolution
- techniques: image processing
- techniques: interferometric
Fingerprint
Dive into the research topics of 'First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole'. Together they form a unique fingerprint.Projects
- 3 Finished
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Physics of Black Hole-Powered Jets
Savolainen, T. (Principal investigator) & Chamani Velasco, W. (Project Member)
01/09/2017 → 31/08/2019
Project: Academy of Finland: Other research funding
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Physics of Black Hole-Powered Jets
Chamani Velasco, W. (Project Member), Savolainen, T. (Principal investigator) & Kiehlmann, S. (Project Member)
01/09/2014 → 31/12/2015
Project: Academy of Finland: Other research funding
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Physics of Black Hole-Powered Jets
Savolainen, T. (Principal investigator)
01/09/2014 → 31/08/2019
Project: Academy of Finland: Other research funding
Equipment
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Metsähovi Radio Observatory
Tammi, J. (Manager)
School of Electrical EngineeringFacility/equipment: Facility