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We report the discovery of bright, fast, radio flashes lasting tens of seconds with the AARTFAAC high-cadence all-sky survey at 60 MHz. The vast majority of these coincide with known, bright radio sources that brighten by factors of up to…

Instrumentation and Methods for Astrophysics · Physics 2021-04-29 Mark J. Kuiack , Ralph A. M. J. Wijers , Aleksandar Shulevski , Antonia Rowlinson

Extreme precision radial-velocity spectrometers enable extreme precision stellar spectroscopy. Searches for low-mass exoplanets around solar-type stars are limited by the physical variability in stellar spectra, such as the short-term…

Solar and Stellar Astrophysics · Physics 2023-11-01 Dainis Dravins , Hans-Günter Ludwig

Scintillation of pulsar radio signals caused by the interstellar medium can in principle be used for interstellar interferometry. Changes of the dynamic spectra as a function of pulsar longitude were in the past interpreted as having…

We investigate the feasibility of detecting and probing various components of the ionized intergalactic medium (IGM) and their turbulent properties at radio frequencies through observations of scatter broadening of compact sources. There is…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-01 J. Y. Koay , J. -P. Macquart

We report on the simultaneous Giant Metrewave Radio Telescope (GMRT) and Algonquin Radio Observatory (ARO) observations at 550-750 MHz of the scintillation of PSR B1508+55, resulting in a $\sim$10,000-km baseline. This regime of measurement…

High Energy Astrophysical Phenomena · Physics 2021-08-18 V. R. Marthi , D. Simard , R. A. Main , U. -L. Pen , M. H. van Kerkwijk , K. Vanderlinde , Y. Gupta , C. Roberts , B. M. Quine

This article presents a novel type of very long baseline astronomical interferometer that uses the fluctuations, as a function of time, of the intensity measured by a quadratic detector, which is a common type of astronomical detector. The…

Instrumentation and Methods for Astrophysics · Physics 2013-09-24 Ermanno F. Borra

The Indian Institute of Astrophysics (IIA) is developing a Multi-Conjugate Adaptive Optics (MCAO) system for the Kodaikanal Tower Telescope (KTT). In this context, we have measured the daytime turbulence strength profile at the Kodaikanal…

Instrumentation and Methods for Astrophysics · Physics 2024-07-22 Saraswathi Kalyani Subramanian , Sridharan Rengaswamy , Prasanna Gajanan Deshmukh , Binukumar G. Nair , Mahesh Babu S

We characterize the low frequency radio-frequency interference (RFI) environment at the Murchison Radio-astronomy Observatory (MRO), the location selected for the low-frequency component of the Square Kilometre Array. Data were collected…

Instrumentation and Methods for Astrophysics · Physics 2018-11-07 Marcin Sokolowski , Randall B. Wayth , Morgan Lewis

Phase stability at low radio frequencies is severely impacted by ionospheric propagation delays. Radio interferometers such as the Giant Metrewave Radio Telescope (GMRT) are capable of detecting changes in the ionosphere's total electron…

Instrumentation and Methods for Astrophysics · Physics 2025-07-01 Dipanjan Banerjee , Abhik Ghosh , Sushanta K Mondal , Parimal Ghosh

Weak measurement amplification, which is considered as a very promising scheme in precision measurement, has been applied to various small physical quantities estimation. Since many quantities can be converted to phase signal, it is thus…

Plastic scintillation detectors are increasingly used to measure dose distributions in the context of radiotherapy treatments. Their water-equivalence, real-time response and high spatial resolution distinguish them from traditional…

Medical Physics · Physics 2021-09-22 Emily Cloutier , Louis Archambault , Luc Beaulieu

It has recently been suggested that the power spectrum of redshifted 21cm fluctuations could be used to measure the scale of baryonic acoustic oscillations (BAOs) during the reionisation era. The resulting measurements are potentially as…

Astrophysics · Physics 2014-11-18 Kirsty J. Rhook , Paul M. Geil , J. Stuart B. Wyithe

Gravitational lensing of gravitational waves provides a powerful probe of the mass density distribution in the universe. Wave optics effects, such as diffraction, make the lensing effect sensitive to the structure around the Fresnel scale,…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-22 So Tanaka , Teruaki Suyama

The HI 21cm global signal from the Cosmic Dawn and the Epoch of Reionization (EoR) offers critical insights into the evolution of our Universe. Yet, its detection presents significant challenges due to its extremely low…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-09 Yue Wang , Xin Wang , Shijie Sun , Fengquan Wu , Shoudong Luo , Xuelei Chen

High time-resolution solar wind magnetic field data is employed to study statistics describing intermittency near the first perihelion (~35.6 Rs) of the Parker Solar Probe mission. A merged dataset employing two instruments on the FIELDS…

Space Physics · Physics 2021-04-21 Rohit Chhiber , William H. Matthaeus , Trevor A. Bowen , Stuart D. Bale

Observation of Interplanetary Scintillation (IPS) provides an important and effective way to study the solar wind and the space weather. A series of IPS observations were conducted by the Five-hundred-meter Aperture Spherical radio…

Solar and Stellar Astrophysics · Physics 2022-08-03 Li-Jia Liu , Bo Peng , Lei Yu , Bin Liu , Ji-Guang Lu , Ye-Zhao Yu , Hong-Wei Xi , Ming Xiong , O. Chang

Optical and near-infrared variability is a well-known property of young stellar objects. However, a growing number of recent studies claim that a considerable fraction of them also exhibit mid-infrared flux changes. With the aim of studying…

Solar and Stellar Astrophysics · Physics 2015-06-04 Á. Kóspál , P. Ábrahám , J. A. Acosta-Pulido , C. P. Dullemond , Th. Henning , M. Kun , Ch. Leinert , A. Moór , N. J. Turner

Radio pulsars, as highly coherent point sources, serve as powerful probes of the ionized interstellar medium (IISM). Pulsar scintillation observations have revealed inverted arclets on the secondary spectrum, indicating quasilinearly…

Astrophysics of Galaxies · Physics 2026-04-14 Zhu Xu , Xun Shi

Recently, we showed that dielectric mesoscale spheres support super-resonance effect, i.e. high-order Mie resonance modes with giant field enhancement. The presence of the surrounding medium leads to a significant influence in the intensity…

Optics · Physics 2022-05-10 Igor V. Minin , Song Zhou , Oleg V. Minin