Publications (32)
Kilogauss magnetic field and jet dynamics in the quasar NRAO 530
Mikhail Lisakov, Svetlana Jorstad, Maciek Wielgus +12
The advancement of the Event Horizon Telescope has enabled the study of relativistic jets in active galactic nuclei down to sub-parsec linear scales even at high redshift. Quasi-si…
An 86-GHz search for Pulsars in the Galactic Center with the Atacama Large Millimeter/submillimeter Array
Kuo Liu, Gregory Desvignes, Ralph P. Eatough +24
We report on the first pulsar and transient survey of the Galactic Center (GC) with the Atacama Large Millimeter/submillimeter Array (ALMA). The observations were conducted during…
Finding AGN with wide-field VLBI observations
Enno Middelberg, Adam Deller, John Morgan +7
VLBI observations are a reliable method to identify AGN, since they require high brightness temperatures for a detection to be made. However, because of the tiny fields of view it…
Detection of pulses from the Vela pulsar at millimeter wavelengths with phased ALMA
Kuo Liu, Andre Young, Robert Wharton +20
We report on the first detection of pulsed radio emission from a radio pulsar with the ALMA telescope. The detection was made in the Band-3 frequency range (85-101 GHz) using ALMA…
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…
Detection of intrinsic source structure at ~3 Schwarzschild radii with Millimeter-VLBI observations of SAGITTARIUS A*
Ru-Sen Lu, Thomas P. Krichbaum, Alan L. Roy +53
We report results from very long baseline interferometric (VLBI) observations of the supermassive black hole in the Galactic center, Sgr A*, at 1.3 mm (230 GHz). The observations w…
Dynamics and geometry of the inner sub-parsec-scale jet in 3C 279 observed with the Event Horizon Telescope
Hendrik Mueller, Sebastiano D. von Fellenberg, Ai-Ling Zeng +275
The 2021 Event Horizon Telescope observations resolve the innermost jet region of the blazar 3C279 with unprecedented detail. The reconstructed images consistently reveal a compact…
A ring-like accretion structure in M87 connecting its black hole and jet
Ru-Sen Lu, Keiichi Asada, Thomas P. Krichbaum +118
The nearby radio galaxy M87 is a prime target for studying black hole accretion and jet formation^{1,2}. Event Horizon Telescope observations of M87 in 2017, at a wavelength of 1.3…
The Variability of the Black-Hole Image in M87 at the Dynamical Time Scale
Kaushik Satapathy, Dimitrios Psaltis, Feryal Ozel +235
The black-hole images obtained with the Event Horizon Telescope (EHT) are expected to be variable at the dynamical timescale near their horizons. For the black hole at the center o…
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…
Precision astrometry of pulsars and other compact radio sources in the globular cluster M15
Franz Kirsten, Wouter Vlemmings, Paulo Freire +3
The globular cluster (GC) M15 (NGC 7078) is host to at least eight pulsars and two low mass X-ray binaries (LMXBs) one of which is also visible in the radio regime. Here we present…
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…
First M87 Event Horizon Telescope Results and the Role of ALMA
Ciriaco Goddi, Geoff Crew, Violette Impellizzeri +41
In April 2019, the Event Horizon Telescope (EHT) collaboration revealed the first image of the candidate super-massive black hole (SMBH) at the centre of the giant elliptical galax…
Persistent Asymmetric Structure of Sagittarius A* on Event Horizon Scales
Vincent L. Fish, Michael D. Johnson, Sheperd S. Doeleman +69
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…
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…
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…
Locating the missing large-scale emission in the jet of M87* with short EHT baselines
Boris Georgiev, Paul Tiede, Sebastiano D. von Fellenberg +280
In Very-Long Baseline Interferometric arrays, nearly co-located stations probe the largest scales and typically cannot resolve the observed source. In the absence of large-scale st…
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…
First frequency phase transfer from the 3 mm to the 1 mm band on an Earth-sized baseline
Sara Issaoun, Dominic W. Pesce, MarÃa J. Rioja +33
Frequency Phase Transfer (FPT) is a technique designed to increase coherence and sensitivity in radio interferometry by making use of the non-dispersive nature of the troposphere t…
High-Angular-Resolution and High-Sensitivity Science Enabled by Beamformed ALMA
Vincent Fish, Walter Alef, James Anderson +66
An international consortium is presently constructing a beamformer for the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile that will be available as a facility instrum…
Demographics of black holes at 100 R scales: accretion flows, jets, and shadows
Dhanya G. Nair, Neil M. Nagar, Venkatessh Ramakrishnan +87
Using the Event Horizon Telescope (EHT), the gravitationally lensed rings around the supermassive black holes (SMBHs) in Messier 87 (M87) and Sagittarius A* (Sgr A*) have now been…
Probing jet base emission of M87* with the 2021 Event Horizon Telescope observations
Saurabh, Hendrik Müller, Sebastiano D. von Fellenberg +282
We investigate the presence and spatial characteristics of the jet base emission in M87* at 230 GHz, enabled by the enhanced uv coverage in the 2021 Event Horizon Telescope (EHT) o…
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…
Full-polarization millimeter wavelength variability of Sagittarius A* during the 2018 EHT campaign
Ezequiel Albentosa-Ruiz, Jasmin E. Washington, Nicola Marchili +272
Sagittarius A* (Srg A*), the supermassive black hole at the center of the Milky Way, provides a unique laboratory to study accretion dynamics and plasma processes near the event ho…
Ring Asymmetry and Spin in M87*
Vadim Bernshteyn, Nicholas S. Conroy, Michi Bauböck +263
Event Horizon Telescope (EHT) images of the supermassive black hole M87* depict an asymmetric ring of emission. General relativistic magnetohydrodynamic (GRMHD) models of M87* and…
Origin of the ring ellipticity in the black hole images of M87*
Rohan Dahale, Ilje Cho, Kotaro Moriyama +273
We investigate the origin of the elliptical ring structure observed in the images of the supermassive black hole M87*, aiming to disentangle contributions from gravitational, astro…
Wide-field VLBA Observations of the Chandra Deep Field South
Enno Middelberg, Adam Deller, John Morgan +7
Wide-field surveys are a commonly-used method for studying thousands of objects simultaneously, to investigate, e.g., the joint evolution of star-forming galaxies and active galact…
Broadband multiwavelength properties of the archetypal blazar 3C 279 during the 2017 Event Horizon Telescope campaign
G. Principe, J. C. Algaba, E. Aviano +529
The archetypal blazar 3C 279 hosts a prominent relativistic jet and exhibits strong broadband variability across the electromagnetic spectrum. In April 2017, the Event Horizon Tele…
A multi-frequency study of sub-parsec jets with the Event Horizon Telescope
Jan Röder, Maciek Wielgus, Andrei P. Lobanov +287
The 2017 observing campaign of the Event Horizon Telescope (EHT) delivered the first very long baseline interferometry (VLBI) images at the observing frequency of 230 GHz, leading…
The putative center in NGC 1052
Anne-Kathrin Baczko, Matthias Kadler, Eduardo Ros +284
Many active galaxies harbor powerful relativistic jets, however, the detailed mechanisms of their formation and acceleration remain poorly understood. To investigate the area of je…
VLBI astrometry of two millisecond pulsars
Zhen Yan, Zhi-qiang Shen, Jian-ping Yuan +3
We present astrometric results on two millisecond pulsars, PSR B1257+12 and PSR J1022+1001, as carried out through VLBI. For PSR B1257+12, a model-independent distance of $710_{\rm…
First Very Long Baseline Interferometry Detections at 870μm
Alexander W. Raymond, Sheperd S. Doeleman, Keiichi Asada +276
The first very long baseline interferometry (VLBI) detections at 870m wavelength (345GHz frequency) are reported, achieving the highest diffraction-limited angular resoluti…