Imaging Reanalyses of EHT Data

The Event Horizon Telescope Collaboration (EHTC) welcomes critical, independent analysis and interpretation of our published results. We publish detailed descriptions of our methods as well as raw data, data products, and analysis scripts to facilitate transparency, rigor, and reproducibility.  

The EHT images of M87 are among the most vetted interferometric images ever published (1,2). Four independent analyses (3,4,5,6) have reconstructed the ring-like structure of M87, employing a diverse set of techniques.  These efforts complement the three imaging and two modeling techniques in the 2019 EHTC papers presenting the first M87 results.  Furthermore, the EHTC and its members have published two additional papers, employing newly developed and independent techniques, that confirm the original results (7,8).  As an ensemble, these multiple independent techniques and efforts are robust against algorithmic bias, parameter selection, or human bias.

Our team has determined that a new re-analysis (9) is based on a flawed understanding of EHTC data and its methods, leading to erroneous conclusions.  Ring-like structures are unambiguously recovered under a broad range of imaging assumptions, including field of view.  Additionally, large-scale jet structures are unconstrained by this high-resolution data.  

We encourage the community to continue to engage with the published EHT data and critically assess the EHT results.The EHT looks forward to revealing new images of M87 and Sgr A* from already existing observing campaigns, and will continue to share data for independent analyses.

  1. EHT Collaboration, 2019, ApJL, 875, 4, First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole

  2. EHT Collaboration, 2019, ApJL, 875, 6,First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole

  3. Arras et al, 2022, Nat. Ast, 6, 259, Variable structures in M87* from space, time and frequency resolved interferometry

  4. Carilli & Thyagarajan, 2022, ApJ, 924, 125, Hybrid Mapping of the Black Hole Shadow in M87

  5. Lockhart & Gralla, 2022, MNRAS, 509, 3643, How narrow is the M87* ring? I. The choice of closure likelihood function

  6. Patel et al, 2022, Reproducibility of the First Image of a Black Hole in the Galaxy M87 from the Event Horizon Telescope (EHT) Collaboration

  7. EHTC et al, 2021, ApJL, 910, 12, First M87 Event Horizon Telescope Results. VII. Polarization of the Ring

  8. Sun & Bouman, 2021,  Deep Probabilistic Imaging: Uncertainty Quantification and Multi-modal Solution Characterization for Computational Imaging

  9. Miyoshi et al, 2022, ApJ, in press:  The jet and resolved features of the central supermassive black hole of M 87 observed with EHT