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Polarimetric studies of pulsars at low radio frequencies provide important observational insights into the pulsar emission mechanism and beam models, and probe the properties of the magneto-ionic interstellar medium (ISM). Aperture arrays…

高能天体物理现象 · 物理学 2019-08-07 Mengyao Xue , S. M. Ord , S. E. Tremblay , N. D. R. Bhat , C. Sobey , B. W. Meyers , S. J. McSweeney , N. A. Swainston

Finding low-mass planets around solar-type stars requires to understand the physical variability of the host star, which greatly exceeds the planet-induced radial-velocity modulation. This project aims at analyzing - observationally and…

太阳与恒星天体物理 · 物理学 2025-09-24 Dainis Dravins , Hans-Günter Ludwig

We present a broadband map of polarized diffuse emission at 167-198 MHz developed from data from the Murchison Widefield Array (MWA). The map is designed to improve visibility simulation and precision calibration for 21 cm Epoch of…

宇宙学与河外天体物理 · 物理学 2021-11-17 Ruby Byrne , Miguel F. Morales , Bryna Hazelton , Ian Sullivan , Nichole Barry , Christene Lynch , Jack L. B. Line , Daniel C. Jacobs

Spatial fluctuations in ultraviolet backgrounds can subtly modulate the distribution of extragalactic sources, a potential signal and systematic for large-scale structure surveys. While this modulation has been shown to be significant for…

宇宙学与河外天体物理 · 物理学 2019-10-16 Phoebe Upton Sanderbeck , Vid Irsic , Matthew McQuinn , Avery Meiksin

Radio continuum emission from galaxies at gigahertz frequencies can be used as an extinction-free tracer of star formation. However, at frequencies of a few hundred megahertz, there is evidence for low-frequency spectral flattening. We wish…

We present an analysis of rotation measure (RM) fluctuations from the Test Region of the Southern Galactic Plane Survey (SGPS), along with emission measure (EM) fluctuations in the same field taken from the Southern H-Alpha Sky Survey…

天体物理学 · 物理学 2009-11-10 M. Haverkorn , B. M. Gaensler , N. M. McClure-Griffiths , John M. Dickey , A. J. Green

We describe an attempt to reconstruct the initial conditions for the formation of cosmological large-scale structure. The power spectrum of the primordial fluctuations is affected by bias, nonlinear evolution and redshift-space distortions,…

天体物理学 · 物理学 2015-06-24 J. A. Peacock , S. J. Dodds

We present the first survey of radio frequency interference (RFI) at the future site of the low frequency Square Kilometre Array (SKA), the Murchison Radio-astronomy Observatory (MRO), that both temporally and spatially resolves the RFI.…

天体物理仪器与方法 · 物理学 2020-09-30 Steven Tingay , Marcin Sokolowski , Randall Wayth , Daniel Ung

We present a targeted search for low-frequency (144--215\,MHz) FRB emission from five repeating FRBs using 23.3\,hr of archival data taken with the Murchison Widefield Array (MWA) Voltage Capture System (VCS) between 2014 September and 2020…

Visibility scintillation resulting from wave propagation through the turbulent ionosphere can be an important sources of noise at low radio frequencies ($\nu\lesssim 200$ MHz). Many low frequency experiments are underway to detect the power…

天体物理仪器与方法 · 物理学 2016-03-16 H. K. Vedantham , L. V. E. Koopmans

We present the results of a pilot study search for Fast Radio Bursts (FRBs) using the Murchison Widefield Array (MWA) at low frequencies (139 - 170 MHz). We utilised MWA data obtained in a routine imaging mode from observations where the…

We report on the first detection of ionospheric disturbances caused by short repeated gamma-ray bursts from the magnetar SGR J1550-5418. Very low frequency (VLF) radio wave data obtained in South America clearly show sudden amplitude and…

高能天体物理现象 · 物理学 2015-05-19 Y. T. Tanaka , J. P. Raulin , F. C. P. Bertoni , P. R. Fagundes , J. Chau , N. J. Schuch , M. Hayakawa , Y. Hobara , T. Terasawa , T. Takahashi

A host of new low-frequency radio telescopes seek to measure the 21-cm transition of neutral hydrogen from the early universe. These telescopes have the potential to directly probe star and galaxy formation at redshifts $20 \gtrsim z…

Turbulent dynamics generate random fluctuations in density and velocity in the Interstellar Medium (ISM) of spiral and dwarf galaxies. Observationally, H~{\sc i} 21-cm radiation provides a good probe of these stochastic processes and helps…

星系天体物理 · 物理学 2018-05-30 Meera Nandakumar

Intensity scintillations of cosmic radio sources are used to study astrophysical plasmas like the ionosphere, the solar wind, and the interstellar medium. Normally these observations are relatively narrow band. With Low Frequency Array…

Several experimental efforts are underway to measure the power spectrum of 21cm fluctuations from the Epoch of Reionization (EoR) using low-frequency radio interferometers. Experiments like the Hydrogen Epoch of Reionization Array (HERA)…

天体物理仪器与方法 · 物理学 2019-06-19 Adam E. Lanman , Jonathan C. Pober

The Murchison Widefield Array (MWA), and its recently-developed Voltage Capture System (VCS), facilitates extending the low-frequency range of pulsar observations at high-time and -frequency resolution in the Southern Hemisphere, providing…

High spatial and temporal resolution images of a sunspot, obtained simultaneously in multiple optical and UV wavelengths, are employed to study the propagation and damping characteristics of slow magnetoacoustic waves up to transition…

太阳与恒星天体物理 · 物理学 2017-09-20 S. Krishna Prasad , D. B. Jess , T. Van Doorsselaere , G. Verth , R. J. Morton , V. Fedun , R. Erdelyi , D. J. Christian

We present a survey of the radio sky accessible from the first station of the Long Wavelength Array (LWA1). Images are presented at nine frequencies between 35 and 80 MHz with spatial resolutions ranging from $4.7^\circ$ to $2.0^\circ$,…

天体物理仪器与方法 · 物理学 2017-07-20 Jayce Dowell , Gregory B. Taylor , Frank K. Schinzel , Namir E. Kassim , Kevin Stovall