no code implementations • 22 Dec 2020 • Paul M. Chesler, Lindy Blackburn, Sheperd S. Doeleman, Michael D. Johnson, James M. Moran, Ramesh Narayan, Maciek Wielgus
We explore the coherent temporal autocorrelation function measured at a single telescope.
General Relativity and Quantum Cosmology High Energy Astrophysical Phenomena
no code implementations • 5 Nov 2018 • Ziyan Zhu, Michael D. Johnson, Ramesh Narayan
This resolution may soon enable measurement of the black hole "shadow" size and asymmetry, predicted to be ${\approx}50\,\mu$as and ${\lesssim} 3\,\mu$as, respectively.
Instrumentation and Methods for Astrophysics Astrophysics of Galaxies
1 code implementation • 19 Mar 2018 • Andrew A. Chael, Michael D. Johnson, Katherine L. Bouman, Lindy L. Blackburn, Kazunori Akiyama, Ramesh Narayan
Closure-only imaging provides results that are as non-committal as possible and allows for reconstructing an image independently from separate amplitude and phase self-calibration.
Instrumentation and Methods for Astrophysics High Energy Astrophysical Phenomena
1 code implementation • 3 Nov 2017 • Katherine L. Bouman, Michael D. Johnson, Adrian V. Dalca, Andrew A. Chael, Freek Roelofs, Sheperd S. Doeleman, William T. Freeman
Most recently, the Event Horizon Telescope (EHT) has extended VLBI to short millimeter wavelengths with a goal of achieving angular resolution sufficient for imaging the event horizons of nearby supermassive black holes.
1 code implementation • 3 Nov 2017 • Michael D. Johnson, Katherine L. Bouman, Lindy Blackburn, Andrew A. Chael, Julian Rosen, Hotaka Shiokawa, Freek Roelofs, Kazunori Akiyama, Vincent L. Fish, Sheperd S. Doeleman
By linking widely separated radio dishes, the technique of very long baseline interferometry (VLBI) can greatly enhance angular resolution in radio astronomy.
Instrumentation and Methods for Astrophysics
no code implementations • 3 Aug 2017 • Freek Roelofs, Michael D. Johnson, Hotaka Shiokawa, Sheperd S. Doeleman, Heino Falcke
Turbulent evolution within the accretion disk is expected on timescales comparable to the orbital period, typically an order of magnitude larger than $t_G$.
High Energy Astrophysical Phenomena
1 code implementation • 17 Oct 2016 • Michael D. Johnson
We present a scattering mitigation framework for radio imaging with very long baseline interferometry (VLBI) that partially overcomes this limitation.
Instrumentation and Methods for Astrophysics Astrophysics of Galaxies
1 code implementation • 19 May 2016 • Andrew A. Chael, Michael D. Johnson, Ramesh Narayan, Sheperd S. Doeleman, John F. C. Wardle, Katherine L. Bouman
Polarimetric MEM is thus an attractive choice for image reconstruction with the
Instrumentation and Methods for Astrophysics Astrophysics of Galaxies
no code implementations • CVPR 2016 • Katherine L. Bouman, Michael D. Johnson, Daniel Zoran, Vincent L. Fish, Sheperd S. Doeleman, William T. Freeman
Very long baseline interferometry (VLBI) is a technique for imaging celestial radio emissions by simultaneously observing a source from telescopes distributed across Earth.