We present the first Event Horizon Telescope (EHT) observations of Sagittarius A$^\ast$ (Sgr A$^\ast$), the Galactic center source associated with a supermassive black hole. These observations were conducted in 2017 using a global interferometric …
We present Event Horizon Telescope (EHT) $1.3 \mathrm{mm}$ measurements of the radio source located at the position of the supermassive black hole Sagittarius A$^\ast$ (Sgr A$^\ast$), collected during the 2017 April $5–11$ campaign. The observations …
We present the first event-horizon-scale images and spatiotemporal analysis of Sgr A$^\ast$ taken with the Event Horizon Telescope in $2017$ April at a wavelength of $1.3 \mathrm{mm}$. Imaging of Sgr A$^\ast$ has been conducted through surveys over a …
In this paper we quantify the temporal variability and image morphology of the horizon-scale emission from Sgr A$^\ast$, as observed by the EHT in $2017$ April at a wavelength of $1.3 \mathrm{mm}$. We find that the Sgr A$^\ast$ data exhibit …
In this paper we provide a first physical interpretation for the Event Horizon Telescope's (EHT) $2017$ observations of Sgr A$^\ast$. Our main approach is to compare resolved EHT data at $230$GHz and unresolved non-EHT observations from radio to …
Astrophysical black holes are expected to be described by the Kerr metric. This is the only stationary, vacuum, axisymmetric metric, without electromagnetic charge, that satisfies Einstein's equations and does not have pathologies outside of the …
In 2017 April, the Event Horizon Telescope (EHT) observed the near-horizon region around the supermassive black hole at the core of the M87 galaxy. These 1.3mm wavelength observations revealed a compact asymmetric ring-like source morphology. This …
Event Horizon Telescope (EHT) observations at 230 GHz have now imaged polarized emission around the supermassive black hole in M87 on event-horizon scales. This polarized synchrotron radiation probes the structure of magnetic fields and the plasma …
Recent developments in compact object astrophysics, especially the discovery of merging neutron stars by LIGO, the imaging of the black hole in M87 by the Event Horizon Telescope, and high- precision astrometry of the Galactic Center at close to the …
When surrounded by a transparent emission region, black holes are expected to reveal a dark shadow caused by gravitational light bending and photon capture at the event horizon. To image and study this phenomenon, we have assembled the Event Horizon …