Publications

2021
Prashant Kocherlakota, Luciano Rezzolla, and Event Horizon Telescope Collaboration. 5/20/2021. “Constraints on non-Einsteinian black-hole charges with the 2019 EHT observations of M87.” Physical Review D, 103, 10, Pp. 40-47. Publisher's Version
J. C. Algaba et al. 4/14/2021. “Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign.” ApJL , 911, Pp. L11. Publisher's Version
EHT Collaboration et al. 3/24/2021. “First M87 Event Horizon Telescope Results. VII. Polarization of the Ring.” ApJL, 910, L12, Pp. 48. Publisher's Version
EHT Collaboration et al. 3/24/2021. “First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near The Event Horizon.” ApJL, 910, L13, Pp. 43. Publisher's Version
C. Goddi et al. 3/24/2021. “Polarimetric Properties of Event Horizon Telescope Targets from ALMA.” ApJL, 910, L14, Pp. 54. Publisher's Version
2020
D. Psaltis et al. 10/2020. “Gravitational Test beyond the First Post-Newtonian Order with the Shadow of the M87 Black Hole.” Physical Review Letters, 125, 14, Pp. 141104. Publisher's Version
T. Bronzwaer et al. 9/2020. “RAPTOR. II. Polarized radiative transfer in curved spacetime.” Astronomy & Astrophysics, 641, A126, Pp. 13. Publisher's Version
M. Wielgus et al. 9/2020. “Monitoring the Morphology of M87* in 2009-2017 with the Event Horizon Telescope.” Astrophysical Journal, 901, 1, Pp. 28. Publisher's Version
E. Kravchenko et al. 5/2020. “Linear polarization in the nucleus of M87 at 7 mm and 1.3 cm.” Astronomy & Astrophysics, 637, L6, Pp. 9. Publisher's Version
J. Dexter et al. 5/2020. “A parameter survey of Sgr A* radiative models from GRMHD simulations with self-consistent electron heating.” Monthly Notices of the Royal Astroonomical Society, 494, 3, Pp. 4168-4186. Publisher's Version
F. Roelofs et al. 4/2020. “SYMBA: An end-to-end VLBI synthetic data generation pipeline. Simulating Event Horizon Telescope observations of M 87 .” Astronomy & Astrophysics, 636, A5, Pp. 19. Publisher's Version
M. Johnson et al. 2020. “Universal interferometric signatures of a black hole's photon ring.” Science Advances, 6, 12, Pp. eaaz1310. Publisher's Version
B. Jeter et al. 2020. “Differentiating Disk and Black Hole Driven Jets with EHT Images of Variability in M87.” MNRAS, 493, 5606. Publisher's Version
J. Y. Kim et al. 2020. “Event Horizon Telescope imaging of the archetypal blazar 3C 279 at an extreme 20 microarcsecond resolution.” Astronomy and Astrophysics, 640, A69, Pp. 21. Publisher's VersionAbstract

3C 279 is an archetypal blazar with a prominent radio jet that show broadband flux density variability across the entire electromagnetic spectrum. We use an ultra-high angular resolution technique - global Very Long Baseline Interferometry (VLBI) at 1.3 mm (230 GHz) - to resolve the innermost jet of 3C 279 in order to study its fine-scale morphology close to the jet base where highly variable γ-ray emission is thought to originate, according to various models. The source was observed during four days in April 2017 with the Event Horizon Telescope at 230 GHz, including the phased Atacama Large Millimeter/submillimeter Array (ALMA), at an angular resolution of ∼20 μas (at a redshift of z = 0.536 this corresponds to ∼0.13 pc ∼ 1700 Schwarzschild radii with a black hole mass MBH = 8 × 108 M). Imaging and model-fitting techniques were applied to the data to parameterize the fine-scale source structure and its variation. We find a multicomponent inner jet morphology with the northernmost component elongated perpendicular to the direction of the jet, as imaged at longer wavelengths. The elongated nuclear structure is consistent on all four observing days and across different imaging methods and model-fitting techniques, and therefore appears robust. Owing to its compactness and brightness, we associate the northern nuclear structure as the VLBI "core". This morphology can be interpreted as either a broad resolved jet base or a spatially bent jet. We also find significant day-to-day variations in the closure phases, which appear most pronounced on the triangles with the longest baselines. Our analysis shows that this variation is related to a systematic change of the source structure. Two inner jet components move non-radially at apparent speeds of ∼15 c and ∼20 c (∼1.3 and ∼1.7 μas day-1, respectively), which more strongly supports the scenario of traveling shocks or instabilities in a bent, possibly rotating jet. The observed apparent speeds are also coincident with the 3C 279 large-scale jet kinematics observed at longer (cm) wavelengths, suggesting no significant jet acceleration between the 1.3 mm core and the outer jet. The intrinsic brightness temperature of the jet components are ≲1010 K, a magnitude or more lower than typical values seen at ≥7 mm wavelengths. The low brightness temperature and morphological complexity suggest that the core region of 3C 279 becomes optically thin at short (mm) wavelengths.

 

The data are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/640/A69 and at http://https://eventhorizontelescope.org/for-astronomers/data
A. Broderick et al. 2020. “THEMIS: A Parameter Estimation Framework for the Event Horizon Telescope.” The Astrophysical Journal, 897, 2, Pp. id. 139. Publisher's Version
R. Gold et al. 2020. “Verification of Radiative Transfer Schemes for the EHT.” The Astrophysical Journal, 897, 2, Pp. id. 148. Publisher's Version

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