English
Related papers

Related papers: Probing interplanetary scintillation using broadba…

200 papers

To increase the number of sources with Very Long Baseline Interferometry (VLBI) astrometry available for comparison with the Gaia results, we have observed 31 young stars with recently reported radio emission. These stars are all in the…

Solar and Stellar Astrophysics · Physics 2024-06-12 Sergio A. Dzib , Laurent Loinard , Ralf Launhardt , Jazmín Ordóñez-Toro

Rossby waves play an important role in mediating the angular momentum of rotating spherical fluids, creating weather on Earth and tuning exoplanet orbits in distant stellar systems (Ogilvie 2014). Their recent discovery in the solar…

Solar and Stellar Astrophysics · Physics 2020-03-18 Krishnendu Mandal , Shravan Hanasoge

In this paper, we report our investigation of pulsar scintillation phenomena by monitoring PSR B0355$+$54 at 2.25 GHz for three successive months using \emph{Kunming 40-m radio telescope}. We have measured the dynamic spectrum, the…

Very long baseline interferometry (VLBI) at millimeter (mm) wavelengths is being employed to resolve event-horizon scale structure of the environment surrounding the Milky-Way black hole, at an angular resolution of a few tens of…

High Energy Astrophysical Phenomena · Physics 2018-09-05 Daniel J. D'Orazio , Abraham Loeb

We have made observations of 98 low-Galactic-latitude pulsars to measure pulse broadening caused by multipath propagation through the interstellar medium. Data were collected with the 305-m Arecibo telescope at four radio frequencies…

We used archival very long baseline interferometry (VLBI) data of active galactic nuclei (AGN) observed from 1.4 GHz to 86 GHz to measure the angular size of VLBI radio cores in 8959 AGNs. We analysed their sky distributions, frequency…

Astrophysics of Galaxies · Physics 2022-08-15 T. A. Koryukova , A. B. Pushkarev , A. V. Plavin , Y. Y. Kovalev

We report the first astrophysical application of the technique of wide-field Interplanetary Scintillation (IPS) with the Murchison Widefield Array (MWA). This powerful technique allows us to identify and measure sub-arcsecond compact…

High Energy Astrophysical Phenomena · Physics 2018-01-10 R. Chhetri , J. Morgan , R. D. Ekers , J-P Macquart , E. M. Sadler , M. Giroletti , J. R. Callingham , S. J. Tingay

We report the results of a successful 12 hour 22 GHz VLBI experiment using a heterogeneous network that includes radio telescopes of the Long Baseline Array (LBA) in Australia and several VLBI stations that regularly observe in geodetic…

Context. Radio-loud active galactic nuclei in the early Universe are rare. The quasars J0906+6930 at redshift z=5.47 and J2102+6015 at z=4.57 stand out from the known sample with their compact emission on milliarcsecond (mas) angular scale…

Astrophysics of Galaxies · Physics 2018-10-17 S. Frey , O. Titov , A. E. Melnikov , P. de Vicente , F. Shu

We present phase-referenced VLBI observations of the radio continuum emission from, and the neutral hydrogen 21 cm absorption toward, the Ultra-Luminous Infrared Galaxy IRAS 17208-0014. The observations were carried out at 1362 MHz using…

Astrophysics · Physics 2009-11-07 E. Momjian , J. D. Romney , C. L. Carilli , T. H. Troland , G. B. Taylor

The properties of dust in the interstellar medium (ISM) nearest the Sun are poorly understood because the low column densities of dust toward nearby stars induce little photometric reddening, rendering the grains largely undetectable.…

Interplanetary solar radio type III bursts provide the means for remotely studying and tracking energetic electrons propagating in the interplanetary medium. Due to the lack of direct radio source imaging, several methods have been…

VLBI astrometry allows coordinates of celestial radio sources to be determined with submilliarcsecond accuracy. In particular, with differential VLBI astrometry, the standard errors of relative positions and proper motions can be as small…

Astrophysics · Physics 2007-05-23 Norbert Bartel

We have carried out a high-precision astrometric analysis of two very-long-baseline-interferometry (VLBI) epochs of observation of the 13 extragalactic radio sources in the complete S5 polar cap sample. The VLBI epochs span a time baseline…

Astrophysics of Galaxies · Physics 2016-11-30 I. Marti-Vidal , F. J. Abellan , J. M. Marcaide , J. C. Guirado , M. A. Perez-Torres , E. Ros

Compact radio sources exhibit scintillation, an interference pattern arising from propagation through inhomogeneous plasma, where scintillation patterns encode the relative distances and velocities of the source, scattering material, and…

High Energy Astrophysical Phenomena · Physics 2023-06-26 R. A. Main , S. Bethapudi , V. R. Marthi , M. L. Bause , D. Z. Li , H. -H. Lin , L. G. Spitler , R. S. Wharton

The Caltech-Jodrell Bank very long baseline interferometry (VLBI) Surveys give detailed 5 GHz VLBI images of several hundred milliarcsecond (mas) radio sources, and the full width at half-maximum angular sizes of the corresponding compact…

Astrophysics · Physics 2009-11-13 J. C. Jackson

We present measurements of the total radio flux density as well as very-long-baseline interferometry (VLBI) images of the star, IM Pegasi, which was used as the guide star for the NASA/Stanford relativity mission Gravity Probe B. We…

Instrumentation and Methods for Astrophysics · Physics 2015-06-04 M. F. Bietenholz , N. Bartel , D. E. Lebach , R. R. Ransom , M. I. Ratner , I. I. Shapiro

At sufficiently low frequencies, no ground-based radio array will be able to produce high resolution images while looking through the ionosphere. A space-based array will be needed to explore the objects and processes which dominate the sky…

The observation and imaging of hundreds or thousands of radio sources with the technique of very long baseline interferometry (VLBI) is a computationally intensive task. However, these surveys allow us to conduct statistical investigations…

Astrophysics of Galaxies · Physics 2017-06-28 Kristóf Rozgonyi , Sándor Frey

Very Long Baseline Interferometry, or VLBI, is the observing technique yielding the highest-resolution images today. Whilst a traditionally large fraction of VLBI observations is concentrating on Active Galactic Nuclei, the number of…

Astrophysics · Physics 2009-06-23 Enno Middelberg , Uwe Bach