"Event Horizon Telescope"

First M87 Event Horizon Telescope Results. VII. Polarization of the Ring

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 …

First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near The Event Horizon

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 …

The event horizon general relativistic magnetohydrodynamic code comparison project

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 …

First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole

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 …

First M87 Event Horizon Telescope Results. II. Array and Instrumentation

The Event Horizon Telescope (EHT) is a very long baseline interferometry (VLBI) array that comprises millimeter- and submillimeter-wavelength telescopes separated by distances comparable to the diameter of the Earth. At a nominal operating wavelength …

First M87 Event Horizon Telescope Results. III. Data Processing and Calibration

We present the calibration and reduction of Event Horizon Telescope (EHT) $1.3$ mm radio wavelength observations of the supermassive black hole candidate at the center of the radio galaxy M87 and the quasar 3C 279, taken during the 2017 April 5--11 …

First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole

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 $\sim 40$ $\mu$as, consistent with the size and shape of the lensed …

First M87 Event Horizon Telescope Results. V. Physical Origin of the Asymmetric Ring

The Event Horizon Telescope (EHT) has mapped the central compact radio source of the elliptical galaxy M87 at $1.3$ mm with unprecedented angular resolution. Here we consider the physical implications of the asymmetric ring seen in the 2017 EHT data. …

First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole

We present measurements of the properties of the central radio source in M87 using Event Horizon Telescope data obtained during the 2017 campaign. We develop and fit geometric crescent models (asymmetric rings with interior brightness depressions) …

Superresolution interferometric imaging with sparse modeling using total squared variation -- Application to imaging the black hole shadow

We propose a new imaging technique for interferometry using sparse modeling, utilizing two regularization terms: the $\ell_1$-norm and a new function named total squared variation (TSV) of the brightness distribution. First, we demonstrate that our …