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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…

In typical adaptive optics applications, the atmospheric residual turbulence affects the wavefront sensor response decreasing its sensitivity. On the other hand, wavefront sensors are generally calibrated in diffraction limited condition,…

Instrumentation and Methods for Astrophysics · Physics 2023-10-10 Guido Agapito , Carmelo Arcidiacono , Simone Esposito

Narrow line Seyfert 1 galaxies (NLSy1s) constitute the AGN subclass associated with systematically smaller black hole masses. A few radio loud ones have been detected in MeV -- GeV energy bands by Fermi and evidence for the presence of…

Astrophysics of Galaxies · Physics 2018-10-23 E. Angelakis , S. Kiehlmann , I. Myserlis , D. Blinov , J. Eggen , R. Itoh , N. Marchili , J. A. Zensus

Current $\gamma$-ray telescopes suffer from a gap in sensitivity in the energy range between 100keV and 100MeV, and no polarisation measurement has ever been done on cosmic sources above 1MeV. Past and present e$^+$e$^-$ pair telescopes are…

Sky models have been used in the past to calibrate individual low radio frequency telescopes. Here we generalize this approach from a single antenna to a two element interferometer and formulate the problem in a manner to allow us to…

Instrumentation and Methods for Astrophysics · Physics 2017-06-28 Divya Oberoi , Rohit Sharma , Alan E. E. Rogers

Measurements of the polarization of radio emission are subject to a number of depolarization effects such as bandwidth depolarization, which is caused by the averaging effect of a finite channel bandwidth combined with the…

Instrumentation and Methods for Astrophysics · Physics 2023-02-08 Maxwell A. Fine , Cameron L. Van Eck , Luke Pratley

Understanding the magnetised Universe is a major challenge in modern astrophysics, and cosmic magnetism has been acknowledged as one of the science key drivers of the most ambitious radio instrument ever planned, the SKA telescope. With…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-27 Valentina Vacca , Federica Govoni , Matteo Murgia , Francesca Loi , Luigina Feretti , Hui Li , Elia Battistelli , Torsten A. Enßlin , Paolo Marchegiani

Polarisation measurements of solar flares at millimetre-waves were used to investigate the magnetic field configuration of the emitting sources. We analyse two solar flares (SOL2013-02-17 and SOL2013-11-05) observed by the POlarisation…

Solar and Stellar Astrophysics · Physics 2020-05-05 Douglas F. da Silva , Paulo J. A. Simões , R. F. Hidalgo Ramírez , Adriana Válio

Context: Ground-based telescopes are susceptible to seeing, an atmospheric phenomenon that reduces the resolving power of large observatories to that of a home telescope. Compensating these effects is therefore critical to realizing the…

Instrumentation and Methods for Astrophysics · Physics 2025-11-11 Jacob Trzaska , Amit Ashok

Coronal magnetic fields are well known to be one of the crucial parameters defining coronal physics and space weather. However, measuring the global coronal magnetic fields remains challenging. The polarization properties of coronal radio…

Solar and Stellar Astrophysics · Physics 2022-07-01 Devojyoti Kansabanik , Divya Oberoi , Surajit Mondal

To determine whether particular sources of gravitational radiation will be detectable by a specific gravitational wave detector, it is necessary to know the sensitivity limits of the instrument. These instrumental sensitivities are often…

General Relativity and Quantum Cosmology · Physics 2009-12-30 Shane L. Larson , William A. Hiscock , Ronald W. Hellings

We present stacking polarized intensity as a means to study the polarization of sources that are too faint to be detected individually in surveys of polarized radio sources. Stacking offers not only high sensitivity to the median signal of…

Astrophysics of Galaxies · Physics 2015-06-19 J. M. Stil , B. W. Keller , S. J. George , A. R. Taylor

In Polarization Discrimination Imaging, the amplitude of a sinusoid from a rotating analyzer, representing residual polarized light and carrying information on the object, is detected with the help of a lock-in amplifier. When turbidity…

Image and Video Processing · Electrical Eng. & Systems 2019-11-05 Samudra Dasgupta , Jithun Nair , Shauryadipta Sarkar , Ram Mohan Vasu , Gargeshwari Venkatasubbiah Anand

Current radio interferometers output multi-petabyte-scale volumes of data per year making the storage, transfer, and processing of this data a sizeable challenge. This challenge is expected to grow with the next-generation telescopes such…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-18 J. K. Chege , L. V. E. Koopmans , A. R. Offringa , B. K. Gehlot , S. A. Brackenhoff , E. Ceccotti , S. Ghosh , C. Höfer , F. G. Mertens , M. Mevius , S. Munshi

We present a broadband spectropolarimetric survey of 563 discrete, mostly unresolved radio sources between 1.3 \& 2.0 GHz using data taken with the Australia Telescope Compact Array (ATCA). We have used rotation measure synthesis to…

Astrophysics of Galaxies · Physics 2015-12-16 C. S. Anderson , B. M. Gaensler , I. J. Feain , T. M. O. Franzen

This paper introduces a novel wavefront sensing approach that relies on the Fourier analysis of a single conventional direct image. In the high Strehl ratio regime, the relation between the phase measured in the Fourier plane and the…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 Frantz Martinache

The performance of the Time Projection Chamber (TPC) polarimeter for the Polarimeter for Relativistic Astrophysical X-ray Sources (PRAXyS) Small Explorer was evaluated using polarized and unpolarized X-ray sources. The PRAXyS mission will…

Instrumentation and Methods for Astrophysics · Physics 2016-10-24 W. B. Iwakiri , J. K. Black , R. Cole , T. Enoto , A. Hayato , J. E. Hill , K. Jahoda , P. Kaaret , T. Kitaguchi , M. Kubota , H. Marlowe , R. McCurdy , Y. Takeuchi , T. Tamagawa

Wide-band radio polarization observations offer the possibility to recover information about the magnetic fields in synchrotron sources, such as details of their three-dimensional configuration, that has previously been inaccessible. The…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Cathy Horellou , Andrew Fletcher

Several radio telescopes have been planned or proposed to be deployed on the Lunar farside in the coming years. These will observe the unexplored ultra-long wavelengths of the electromagnetic spectrum from the lunar farside's unique…

Instrumentation and Methods for Astrophysics · Physics 2025-10-17 Nivedita Mahesh , Judd D Bowman , Bharat Gehlot , Danny Jacobs

We study the sensitivities of space infrared interferometers. We formulate the signal-to-noise ratios of infrared images obtained by aperture synthesis in the presence of source shot noise, background shot noise and detector read noise. We…

Astrophysics · Physics 2009-10-31 Tadashi Nakajima , Hideo Matsuhara
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