Now showing items 1-7 of 7

• #### 1.3 mm Wavelength VLBI of Sagittarius A*: Detection of Time-Variable Emission on Event Horizon Scales ﻿

(IOP Publishing, 2011)
Sagittarius A*, the ~4 × 106 M ☉ black hole candidate at the Galactic center, can be studied on Schwarzschild radius scales with (sub)millimeter wavelength very long baseline interferometry (VLBI). We report on 1.3 mm ...
• #### 230 GHz VLBI observations of M87: event-horizon-scale structure at the enhanced very-high-energy γ-ray state in 2012 ﻿

(IOP Publishing, 2015)
We report on 230 GHz (1.3 mm) VLBI observations of M87 with the Event Horizon Telescope using antennas on Mauna Kea in Hawaii, Mt. Graham in Arizona and Cedar Flat in California. For the first time, we have acquired 230 ...
• #### Atmospheric Phase Correction Using Total Power Radiometry at the Submillimeter Array ﻿

(IOP Publishing, 2004)
Phase noise caused by an inhomogeneous, time-variable water vapor distribution in our atmosphere reduces the angular resolution, visibility amplitude and coherence time of millimeter and submillimeter wavelength interferometers. ...
• #### The High-Density Ionized Gas in the Central Parsec of the Galaxy ﻿

(American Astronomical Society, 2010)
We report a study of the $H30\alpha$ line emission at 1.3 mm from the region around Sgr A* made with the Submillimeter Array at a resolution of 2'' over a field of 60'' (2 pc) and a velocity range of \(-360 to +345 km ...
• #### Jet-Launching Structure Resolved Near the Supermassive Black Hole in M87 ﻿

(American Association for the Advancement of Science (AAAS), 2012)
Approximately 10% of active galactic nuclei exhibit relativistic jets, which are powered by accretion of matter onto super massive black holes. While the measured width profiles of such jets on large scales agree with ...
• #### Persistent Asymmetric Structure of Sagittarius A* on Event Horizon Scales ﻿

(American Astronomical Society, 2016)
The Galactic Center black hole Sagittarius A* (Sgr A*) is a prime observing target for the Event Horizon Telescope (EHT), which can resolve the 1.3 mm emission from this source on angular scales comparable to that of the ...
• #### Resolved magnetic-field structure and variability near the event horizon of Sagittarius A ﻿

(American Association for the Advancement of Science (AAAS), 2015)
Near a black hole, differential rotation of a magnetized accretion disk is thought to produce an instability that amplifies weak magnetic fields, driving accretion and outflow. These magnetic fields would naturally give ...