English
Related papers

Related papers: In-field phasing at the upgraded GMRT

200 papers

We report on the results of multi-frequency follow-up observations of three pulsars (PSRs J0026+6320, J2208+5500 and J2217+5733) discovered with the Giant Metrewave Radio Telescope (GMRT). These observations were carried out with the GMRT…

High Energy Astrophysical Phenomena · Physics 2019-01-07 Mayuresh P. Surnis , Bhal Chandra Joshi , Maura A. McLaughlin , Krishnakumar M. A. , Manoharan P. K. , Arun Naidu

We report on slow phase variations of the response of the space-ground radio interferometer RadioAstron during observations of pulsar B0329+54. The phase variations are due to the ionosphere and clearly distinguishable from effects of…

Astrophysics of Galaxies · Physics 2021-07-14 M. V. Popov , N. Bartel , M. S. Burgin , T. V. Smirnova , V. A. Soglasnov

The primary goal of the pulsar timing array projects is to detect ultra-low-frequency gravitational waves. The pulsar data sets are affected by numerous noise processes including varying dispersive delays in the interstellar medium and from…

Instrumentation and Methods for Astrophysics · Physics 2017-10-11 Ze-xi Niu , George Hobbs , Jing-bo Wang , Shi Dai

One major problem of phase-referencing VLBI observations are phase errors due to the unknown tropospheric zenith delay at each antenna. These errors degrade the quality of the phase-referenced image and limit the achievable astrometric…

Astrophysics · Physics 2009-04-09 A. Brunthaler , M. J. Reid , H. Falcke

We present two estimators to quantify the angular power spectrum of the sky signal directly from the visibilities measured in radio interferometric observations. This is relevant for both the foregrounds and the cosmological 21-cm signal…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-11 Samir Choudhuri , Somnath Bharadwaj , Abhik Ghosh , SK. Saiyad Ali

Wireless power transfer (WPT) technologies hold promise for enhancing device autonomy, particularly for energy-limited IoT systems. This paper presents experimental results on coherent and non-coherent transmit diversity approaches for WPT,…

Broadband energy-time entanglement can be used to enhance the rate of two-photon absorption (TPA) by combining a precise two-photon resonance with a very short coincidence time. Because of this short coincidence time, broadband TPA is not…

Quantum Physics · Physics 2023-12-04 Baihong Li , Holger F. Hofmann

We present the first spectropolarimetric radio observations that apply Rotation Measure (RM) Synthesis to interferometric data from the Giant Metrewave Radio Telescope (GMRT) at 610 MHz. Spectropolarimetry requires measurement of a large…

Instrumentation and Methods for Astrophysics · Physics 2013-09-19 J. S. Farnes , D. A. Green , N. G. Kantharia

Obtaining lensing time delay measurements requires long-term monitoring campaigns with a high enough resolution (< 1 arcsec) to separate the multiple images. In the radio, a limited number of high-resolution interferometer arrays make these…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-21 G. Gurkan , N. Jackson , L. V. E. Koopmans , C. D. Fassnacht , A. Berciano Alba

The discovery and timing follow-up of millisecond pulsars (MSPs) are necessary not just for their usefulness in Pulsar Timing Arrays (PTAs) but also for investigating their own intriguing properties. In this work, we provide the findings of…

High Energy Astrophysical Phenomena · Physics 2023-11-01 Shyam S. Sharma , Jayanta Roy , Bhaswati Bhattacharyya , Lina Levin

During February 2016, CSIRO Astronomy and Space Science and the Max-Planck-Institute for Radio Astronomy installed, commissioned and carried out science observations with a phased array feed (PAF) receiver system on the 64m diameter Parkes…

Instrumentation and Methods for Astrophysics · Physics 2017-07-19 X. Deng , A. P. Chippendale , G. Hobbs , S. Johnston , S. Dai , D. George , M. Kramer , R. Karuppusamy , M. Malenta , L. Spitler , T. Tzioumis , G. Wieching

Black widows are millisecond pulsars ablating their companions. The material blown from the companion blocks the radio emission, resulting in radio eclipses. The properties of the eclipse medium are poorly understood. Here, we present…

High Energy Astrophysical Phenomena · Physics 2023-07-26 S. Q. Wang , J. B. Wang , D. Z. Li , J. M. Yao , R. N. Manchester , G. Hobbs , N. Wang , S. Dai , H. Xu , R. Luo , Y. Feng , W. Y. Wang , D. Li , Y. W. Yu , Z. X. Du , C. H. Niu , S. B. Zhang , C. M. Zhang

We describe a method for spectral cleaning and timing calibration of short voltage time series data from individual radio interferometer receivers. It makes use of the phase differences in Fast Fourier Transform (FFT) spectra across antenna…

Instrumentation and Methods for Astrophysics · Physics 2016-05-04 A. Corstanje , S. Buitink , J. E. Enriquez , H. Falcke , J. R. Hörandel , M. Krause , A. Nelles , J. P. Rachen , P. Schellart , O. Scholten , S. ter Veen , S. Thoudam , T. N. G. Trinh

High-precision measurements are crucial for testing the fundamental laws of nature and for advancing the technological frontier. Clock interferometry, where particles with an internal clock are coherently split and recombined along two…

In regions with strongly varying electron density, radio emission can be magnified significantly by plasma lensing. In the presence of magnetic fields, magnification in time and frequency will be different for two circular polarizations. We…

High Energy Astrophysical Phenomena · Physics 2019-02-13 Dongzi Li , Fang Xi Lin , Robert Main , Ue-Li Pen , Marten H. van Kerkwijk , I-Sheng Yang

This paper describes a comprehensive measurement model for the error budget of pulse arrival times with emphasis on intrinsic pulse jitterand plasma propagation effects (particularly interstellar scattering), which are stochastic in time…

Instrumentation and Methods for Astrophysics · Physics 2010-10-20 J. M. Cordes , R. M. Shannon

We review millimeter interferometric phase variations caused by variations in the precipitable water vapor content of the troposphere, and we discuss techniques proposed to correct for these variations. We present observations with the Very…

Astrophysics · Physics 2015-06-24 C. L. Carilli , M. A. Holdaway

During strong magnetic storms, the errors of determination of the range, frequency Doppler shift and angles of arrival of transionospheric radio signals exceeds the one for magnetically quiet days by one order of magnitude as a minimum.…

Geophysics · Physics 2007-05-23 E. L. Afraimovich

Phased array feeds (PAFs) for reflector antennas offer the potential for increased reflector field of view and faster survey speeds. To address some of the development challenges that remain for scientifically useful PAFs, including…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 Jonathan Landon , Michael Elmer , Jacob Waldron , David Jones , Alan Stemmons , Brian D. Jeffs , Karl F. Warnick , J. Richard Fisher , Roger D. Norrod

While observations of many high-precision radio pulsars of order $\lesssim1~\mu$s across the sky are needed for the detection and characterization of a stochastic background of low-frequency gravitational waves (GWs), sensitivity to single…

High Energy Astrophysical Phenomena · Physics 2021-06-02 M. T. Lam , J. S. Hazboun