Publications (18)
Event Horizon Telescope observations of the jet launching and collimation in Centaurus A
Michael Janssen, Heino Falcke, Matthias Kadler +236
Very-long-baseline interferometry (VLBI) observations of active galactic nuclei at millimeter wavelengths have the power to reveal the launching and initial collimation region of e…
Observations of gas flows inside a protoplanetary gap
Simon Casassus, Gerrit van der Plas, Sebastian Perez M. +16
Gaseous giant planet formation is thought to occur in the first few million years following stellar birth. Models predict that giant planet formation carves a deep gap in the dust…
Calibration of ALMA as a phased array: ALMA observations during the 2017 VLBI campaign
Ciriaco Goddi, Ivan Marti-Vidal, Hugo Messias +14
We present a detailed description of the special procedures for calibration and quality assurance of Atacama Large Millimeter/submillimeter Array (ALMA) observations in Very Long B…
Precise geodesy with the Very Long Baseline Array
Leonid Petrov, David Gordon, John Gipson +5
We report on a program of geodetic measurements between 1994 and 2007 which used the Very Long Baseline Array and up to 10 globally distributed antennas. One of the goals of this p…
Comparison of Polarized Radiative Transfer Codes used by the EHT Collaboration
Ben S. Prather, Cora Prather, Jason Dexter +271
Interpretation of resolved polarized images of black holes by the Event Horizon Telescope (EHT) requires predictions of the polarized emission observable by an Earth-based instrume…
The Polarized Image of a Synchrotron Emitting Ring of Gas Orbiting a Black Hole
Ramesh Narayan, Daniel C. M. Palumbo, Michael D. Johnson +237
Synchrotron radiation from hot gas near a black hole results in a polarized image. The image polarization is determined by effects including the orientation of the magnetic field i…
Long Baseline Observations of the HD100546 Protoplanetary Disk with ALMA
Sebastián Pérez, Simon Casassus, Antonio Hales +9
Using the Atacama Large Millimeter/submillimeter Array (ALMA), we observed the young Herbig star HD 100546, host to a prominent disk with a deep, wide gap in the dust. The high-res…
VLBA Calibrator Survey: Astrometric and Image Results
Leonid Petrov, David Grodon, Anthony Beasley +1
Positions and maps of 1608 new compact sources were obtained in twelve sessions observed during 1994--2002 at the VLBA network at 8.4/2.3 GHz. These sources are recommended for use…
The Position/Structure Stability of Four ICRF2 Sources
Ed Fomalont, Kenneth Johnston, Alan Fey +3
Four close radio sources in the International Celestial Reference Frame (ICRF) catalog were observed using phase referencing with the VLBA at 43, 23 and 8.6 GHz, and with VERA at 2…
The internal Faraday screen of Sagittarius A*
Maciek Wielgus, Sara Issaoun, Ivan Marti-Vidal +5
We report on 85-101 GHz light curves of the Galactic Center supermassive black hole, Sagittarius A* (Sgr A*), observed in April 2017 with the Atacama Large Millimeter/submillimeter…
A search for pulsars around Sgr A* in the first Event Horizon Telescope dataset
Pablo Torne, Kuo Liu, Ralph P. Eatough +282
The Event Horizon Telescope (EHT) observed in 2017 the supermassive black hole at the center of the Milky Way, Sagittarius A* (Sgr A*), at a frequency of 228.1 GHz (=1.3 mm). T…
Millimeter light curves of Sagittarius A* observed during the 2017 Event Horizon Telescope campaign
Maciek Wielgus, Nicola Marchili, Ivan Marti-Vidal +28
The Event Horizon Telescope (EHT) observed the compact radio source, Sagittarius A* (Sgr A*), in the Galactic Center on 2017 April 5-11 in the 1.3 millimeter wavelength band. At th…
Gravitational Test Beyond the First Post-Newtonian Order with the Shadow of the M87 Black Hole
Dimitrios Psaltis, Lia Medeiros, Pierre Christian +185
The 2017 Event Horizon Telescope (EHT) observations of the central source in M87 have led to the first measurement of the size of a black-hole shadow. This observation offers a new…
Total Power Map to Visibilities (TP2VIS): Joint Deconvolution of ALMA 12m, 7m, and Total Power Array Data
Jin Koda, Peter Teuben, Tsuyoshi Sawada +2
We present a new package for joint deconvolution of ALMA 12m, 7m, and Total Power (TP) data, dubbed ``Total Power Map to Visibilities (TP2VIS)". It converts a TP (single-dish) map…
General relativistic model for experimental measurement of the speed of propagation of gravity by VLBI
Sergei Kopeikin, Ed Fomalont
A relativistic sub-picosecond model of gravitational time delay in radio astronomical observations is worked out and a new experimental test of general relativity is discussed in w…
Constraints on black-hole charges with the 2017 EHT observations of M87*
Prashant Kocherlakota, Luciano Rezzolla, Heino Falcke +234
Our understanding of strong gravity near supermassive compact objects has recently improved thanks to the measurements made by the Event Horizon Telescope (EHT). We use here the M8…
Astrometry of Cassini with the VLBA to Improve the Saturn Ephemeris
Dayton L. Jones, William M. Folkner, Robert A. Jacobson +4
Planetary ephemerides have been developed and improved over centuries. They are a fundamental tool for understanding solar system dynamics, and essential for planetary and small bo…
Phase Characteristics of the ALMA 3 km Baseline Data
Satoki Matsushita, Yoshiharu Asaki, Ryohei Kawabe +3
We present the phase characteristics study of the Atacama Large Millimeter/submillimeter Array (ALMA) long (up to 3 km) baseline, which is the longest baseline tested so far using…