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We present the findings from the Prototype All-Sky Imager (PASI), a backend correlator of the first station of the Long Wavelength Array (LWA1), which has recorded over 11,000 hours of all-sky images at frequencies between 25 and 75 MHz. In…

Wide-Area Linear Optical Polarimeter (WALOP)-South is the first wide-field and survey-capacity polarimeter in the optical wavelengths. On schedule for commissioning in 2024, it will be mounted on the 1 m SAAO telescope in Sutherland…

The Ultra-Long Wavelength (ULW) regime of longer than 10 m (corresponding to frequencies below 30 MHz), remains as the last virtually unexplored window in radio astronomy, and is presently attracting considerable attention as an area of…

Instrumentation and Methods for Astrophysics · Physics 2019-09-04 Linjie Chen , Yihua Yan

The search for the spectral signature of hydrogen from the formation of the first stars, known as Cosmic Dawn or First Light, is an ongoing effort around the world. The signature should present itself as a decrease in the temperature of the…

Instrumentation and Methods for Astrophysics · Physics 2021-12-30 Christopher DiLullo , Gregory B. Taylor , Jayce Dowell

The first prototype of LST (LST-1) for the Cherenkov Telescope Array has been in commissioning phase since 2018 and already started scientific observations with the low energy threshold around a few tens of GeV. In 2021, LST-1 observed BL…

High Energy Astrophysical Phenomena · Physics 2023-09-19 Seiya Nozaki , Katsuaki Asano , Juan Escudero , Gabriel Emery , Chaitanya Priyadarshi

The Large-aperture Experiment to detect the Dark Age (LEDA) was designed to measure the 21-cm signal from neutral hydrogen at Cosmic Dawn, $z \approx $15-30. Using observations made with the $\approx $ 200 m diameter core of the Owens…

The FIRST survey, begun over twenty years ago, provides the definitive high-resolution map of the radio sky. This VLA survey reaches a 20cm detection sensitivity of 1 mJy over 10,575 deg**2 largely coincident with the SDSS area. Images and…

Astrophysics of Galaxies · Physics 2015-06-23 David J. Helfand , Richard L. White , Robert H. Becker

The wide adoption of low-frequency radio interferometers as a tool for deeper and higher resolution astronomical observations has revolutionised radio astronomy. Despite their construction from static, relatively simple dipoles, the sheer…

Instrumentation and Methods for Astrophysics · Physics 2021-02-02 A. Chokshi , J. L. B. Line , N. Barry , D. Ung , D. Kenney , A. McPhail , A. Williams , R. L. Webster

As a backend to the first station of the Long Wavelength Array (LWA1) the Prototype All Sky Imager (PASI) has been imaging the sky $>$ -26$^{\circ}$ declination during 34 Gamma Ray Bursts (GRBs) between January 2012 and May 2013. Using this…

High Energy Astrophysical Phenomena · Physics 2015-06-19 K. S. Obenberger , J. M. Hartman , G. B. Taylor , J. Craig , J. Dowell , J. F. Helmboldt , P. A. Henning , F. K. Schinzel , T. L. Wilson

In radio astronomy, the Ultra-Long Wavelengths (ULW) regime of longer than 10 m (frequencies below 30 MHz), remains the last virtually unexplored window of the celestial electromagnetic spectrum. The strength of the science case for…

Instrumentation and Methods for Astrophysics · Physics 2018-02-23 Linjie Chen , Amin Aminaei , Leonid I. Gurvits , Marc Klein Wolt , Hamid Reza Pourshaghaghi , Yihua Yan , Heino Falcke

This report was submitted as part of the SKA Low Frequency Aperture Array Critical Design Review describing the design of the SKA1-LOW station that took place between 2013 and 2018. The SKA1 LOW field station is inscribed in a circular area…

Lyman-$\alpha$ spheres, i.e. regions around the first stars which are illuminated by Lyman-$\alpha$ photons and show 21cm absorption feature against the CMB, are smoking guns at the dawn of the reionization epoch. Though overwhelming radio…

Astrophysics · Physics 2011-02-11 Guoliang Li , Pengjie Zhang , Xuelei Chen

WALOP (Wide-Area Linear Optical Polarimeter)-South, to be mounted on the 1m SAAO telescope in South Africa, is first of the two WALOP instruments currently under development for carrying out the PASIPHAE survey. Scheduled for commissioning…

Following the selection of The Gravitational Universe by ESA, and the successful flight of LISA Pathfinder, the LISA Consortium now proposes a 4 year mission in response to ESA's call for missions for L3. The observatory will be based on…

Extended 21cm absorption regions (dubbed ``21cm absorption halos'') around first galaxies at $z\sim 30$ are likely the first distinctive structures accessible to radio observations. Though the radio array capable of detecting and resolving…

Astrophysics · Physics 2009-11-11 Pengjie Zhang , Zheng Zheng , Renyue Cen

We report the discovery of the first new pulsar with the Murchison Widefield Array (MWA), PSR J0036$-$1033, a long-period (0.9 s) nonrecycled pulsar with a dispersion measure (DM) of 23.1 ${\rm pc\,cm^{-3}}$. It was found after processing…

This paper considers the suitability of a number of emerging and future instruments for the study of radio recombination lines (RRLs) at frequencies below 200 MHz. These lines arise only in low-density regions of the ionized interstellar…

Astrophysics of Galaxies · Physics 2015-05-20 W. M. Peters , T. Joseph W. Lazio , T. E. Clarke , W. C. Erickson , N. E. Kassim

We present results from the first all-sky radio survey in circular polarisation. The survey uses the Murchison Widefield Array (MWA) to cover 30900 sq. deg., over declinations south of +30$^{\circ}$ and north of -86$^{\circ}$ centred at 200…

Astrophysics of Galaxies · Physics 2018-06-06 Emil Lenc , Tara Murphy , Christene R. Lynch , David L. Kaplan , Suinan Zhang

We present deep polarimetric observations at 154 MHz with the Murchison Widefield Array (MWA), covering 625 deg^2 centered on RA=0 h, Dec=-27 deg. The sensitivity available in our deep observations allows an in-band, frequency-dependent…

The low-frequency sky below $\sim$15 MHz (20 m) is obscured by the Earth's ionosphere, the layer of charged particles above the neutral atmosphere. Single spacecraft have made measurements in this band, but cannot achieve high or even…

Instrumentation and Methods for Astrophysics · Physics 2024-04-15 Mary Knapp , Lenny Paritsky , Ekaterina Kononov , Melodie M. Kao