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Related papers: LBCS: the LOFAR Long-Baseline Calibrator Survey

200 papers

The large majority of BL Lacertae objects belonging to the 1 Jy sample, the class prototype for radio-selected sources, are thought to emit most of their synchrotron power in the far IR band. Ironically, this spectral region is very…

Astrophysics · Physics 2007-05-23 P. Padovani , P. Giommi , P. Abraham , S. Csizmadia , A. Moor

The turbulent ionosphere causes phase shifts to incoming radio waves on a broad range of temporal and spatial scales. When an interferometer is not sufficiently calibrated for the direction-dependent ionospheric effects, the time-varying…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-02 S. A. Brackenhoff , M. Mevius , L. V. E. Koopmans , A. Offringa , E. Ceccotti , J. K. Chege , B. K. Gehlot , S. Ghosh , C. Höfer , F. G. Mertens , S. Munshi , S. Zaroubi

We present the results of the five mid-IR 15 microns (12-18 microns LW3 band) ISOCAM Guaranteed Time Extragalactic Surveys performed in the regions of the Lockman Hole and Marano Field. The roughly 1000 sources detected, 600 of which have a…

Extension of very long baseline interferometry (VLBI) to observing wavelengths shorter than 1.3mm provides exceptional angular resolution (~20 micro arcsec) and access to new spectral regimes for the study of astrophysical phenomena. To…

Instrumentation and Methods for Astrophysics · Physics 2011-06-02 Sheperd Doeleman , Tao Mai , Alan Rogers , John Hartnett , Michael Tobar , Nitin Nand

Laser Comb Wavelength calibration shows that the ThAr one is locally unreliable with possible deviations of up to 100 m/s within one order range, while delivering an overall 1 m/s accuracy (Wilken et al 2009). Such deviation corresponds to…

Cosmology and Nongalactic Astrophysics · Physics 2009-10-27 Miriam Centurión , Paolo Molaro , Sergei Levshakov

Channel measurements in MIMO systems hinge on precise synchronization. While methods for time and frequency synchronization are well established, maintaining real-time phase coherence remains an open requirement for many MIMO systems. Phase…

Signal Processing · Electrical Eng. & Systems 2026-02-19 Carl Collmann , Ahmad Nimr , Gerhard Fettweis

The next generation of radio surveys is going to be transformative for cosmology and other aspects of our understanding of astrophysics. Realistic simulations of radio observations are essential for the design and planning of radio surveys.…

Instrumentation and Methods for Astrophysics · Physics 2025-07-30 Tobias Vičánek Martínez , Henrik W. Edler , Marcus Brüggen

This paper presents accurate absolute positions from a 24 GHz Very Long Baseline Array (VLBA) search for compact extragalactic sources in an area where the density of known calibrators with precise coordinates is low. The goals were to…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 L. Petrov , Y. Y. Kovalev , E. B. Fomalont , D. Gordon

The Laser Interferometer Space Antenna (LISA) is expected to provide the largest observational sample of binary systems of faint sub-solar mass compact objects, in particular white-dwarfs, whose radiation is monochromatic over most of the…

General Relativity and Quantum Cosmology · Physics 2009-11-10 A. Vecchio , E. D. L. Wickham

Instruments targeting 21~cm emission at high redshifts need a spectral dynamic range of better than ten thousand to distinguish the 21~cm background against bright foregrounds. Systematics arising from the antenna pattern are a leading…

Instrumentation and Methods for Astrophysics · Physics 2026-05-21 Daniel C. Jacobs

We investigate the utility of the Tunable Filters (TFs) for obtaining flux calibrated emission line maps of extended objects such as galactic nebulae and nearby galaxies, using the OSIRIS instrument at the 10.4-m GTC. Despite a relatively…

We present the design concept of the wavelength calibration system for the Habitable-zone Planet Finder instrument (HPF), a precision radial velocity (RV) spectrograph designed to detect terrestrial-mass planets around M-dwarfs. HPF is a…

Instrumentation and Methods for Astrophysics · Physics 2014-08-19 Samuel Halverson , Suvrath Mahadevan , Lawrence Ramsey , Ryan Terrien , Arpita Roy , Christian Schwab , Chad Bender , Fred Hearty , Eric Levi , Steve Osterman , Gabe Ycas , Scott Diddams

We analyze the quasar two-point correlation function (2pCF) within the redshift interval $0.8<z<2.2$ using a sample of 52303 quasars selected from the recent 7th Data Release of the Sloan Digital Sky Survey. Our approach to 2pCF uses a…

Cosmology and Nongalactic Astrophysics · Physics 2010-10-12 G. Ivashchenko , V. I. Zhdanov , A. V. Tugay

We propose a probabilistic framework for performing simultaneous estimation of source structure and fringe-fitting parameters in Very Long Baseline Interferometry (VLBI) observations. As a first step, we demonstrate this technique through…

Instrumentation and Methods for Astrophysics · Physics 2020-06-10 Iniyan Natarajan , Roger Deane , Ilse van Bemmel , Huib Jan van Langevelde , Des Small , Mark Kettenis , Zsolt Paragi , Oleg Smirnov , Arpad Szomoru

We provide the most accurate estimate yet of the bright end of the infrared (IR) luminosity functions (LFs) and the abundance of hyperluminous IR galaxies (HLIRGs) with IR luminosities > 10^13 L_solar, thanks to the combination of the high…

The LOFAR Two-metre Sky Survey (LoTSS) is an ongoing sensitive, high-resolution 120-168 MHz survey of the Northern sky with diverse and ambitious science goals. Many of the scientific objectives of LoTSS rely upon, or are enhanced by, the…

The third iteration of the International Celestial Reference Frame (ICRF3) is made up of 4536 quasars observed at S/X bands using Very Long baseline Interferometry (VLBI). These sources are high redshift quasars, typically between $1<z<2$,…

Astrophysics of Galaxies · Physics 2021-09-08 Lucas R. Hunt , Megan C. Johnson , Phillip J. Cigan , David Gordon , John Spitzak

We aim to evaluate the possibility of improving the ICRS realization starting from the ICRF2 catalogue by investigating the coordinate time series of radio sources observed by VLBI between 1979 and 2016. Sources with long observational…

Astrophysics of Galaxies · Physics 2017-02-14 N. Liu , J. -C. Liu , Z. Zhu

We have conducted two pilot surveys for radio pulsars and fast transients with the Low-Frequency Array (LOFAR) around 140 MHz and here report on the first low-frequency fast-radio burst limit and the discovery of two new pulsars. The first…