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Related papers: SAGECal performance with large sky models

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Characterizing the variability of the extragalactic sources used for calibration in the Atacama Large Millimeter/Sub-millimeter Array (ALMA) is key to assess the flux scale uncertainty of science observations. To this end, we model the…

Instrumentation and Methods for Astrophysics · Physics 2019-08-12 A. E. Guzmán , C. Verdugo , H. Nagai , Y. Contreras , G. Marinello , R. Kneissl , K. Nakanishi , J. Ueda

We describe the INTEGRAL reference catalog which classifies previously known bright X-ray and gamma-ray sources before the launch of INTEGRAL. These sources are, or have been at least once, brighter than ~1 mCrab above 3 keV, and are…

Astrophysics · Physics 2009-11-10 Ken Ebisawa , G. Bourban , A. Bodaghee , N. Mowlavi , T. J. -L. Courvoisier

We have studied the science rationale, goals and requirements for a mission aimed at using the gravitational lensing from the Sun as a way of achieving high angular resolution and high signal amplification. We find that such a mission…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Slava G. Turyshev , B-G Andersson

We present a classification-based approach to identify quasi-stellar radio sources (quasars) in the Sloan Digital Sky Survey and evaluate its performance on a manually labeled training set. While reasonable results can already be obtained…

Instrumentation and Methods for Astrophysics · Physics 2016-11-18 Fabian Gieseke , Kai Lars Polsterer , Andreas Thom , Peter-Christian Zinn , Dominik Bomanns , Ralf-Jürgen Dettmar , Oliver Kramer , Jan Vahrenhold

Strong gravitational lenses are unique cosmological probes. These produce multiple images of a single source. Whether a single galaxy, a group or a cluster, extracting cosmologically relevant information requires an accurate modeling of the…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-13 Irène Balmès

The new wide-field radio telescopes, such as: ASKAP, MWA, LOFAR, eVLA and SKA; will produce spectral-imaging data-cubes (SIDC) of unprecedented size -- in the order of hundreds of Petabytes. Servicing such data as images to the end-user in…

Instrumentation and Methods for Astrophysics · Physics 2014-07-02 Vyacheslav V. Kitaeff , Andrew Cannon , Andreas Wicenec , David Taubman

The results of the analysis of 205 brightest sources ( $S>15$ mJy), which were found in the sky survey at the declination of the pulsar in the Crab Nebula, are presented. The survey was conducted at a frequency of 4.7~GHz using a three-beam…

High Energy Astrophysical Phenomena · Physics 2024-11-27 A. A. Kudryashova , N. N. Bursov , S. A. Trushkin

Numerical methods play an ever more important role in astrophysics. This is especially true in theoretical works, but of course, even in purely observational projects, data analysis without massive use of computational methods has become…

Astrophysics of Galaxies · Physics 2014-12-18 Volker Springel

Two fundamental research tasks in science and engineering are forward predictions and data inversion. This article introduces a recent R package RobustCalibration for Bayesian data inversion and model calibration by experiments and field…

Computation · Statistics 2024-02-20 Mengyang Gu

Radio astronomy studies the Universe by observing the radio emissions of celestial bodies. Different methods can be used to recover the sky brightness distribution (SBD), which describes the distribution of celestial sources from recorded…

Instrumentation and Methods for Astrophysics · Physics 2024-07-11 X. Li , K. Adamek , W. Armour

Over the past decade advancements in the understanding of several astrophysical phenomena have allowed us to infer a concordance cosmological model that successfully accounts for most of the observations of our universe. This has opened up…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-13 Irène Balmès , Pier-Stefano Corasaniti

We present a point source catalogue of the Large Magellanic Cloud (LMC) using observations from the MeerKAT radio telescope across a broad frequency band centred at 1295 MHz (L-band) with 12 sub-bands and an angular resolution of 8 arcsec x…

We study $e^{\pm}$ pair plasmas in pair equilibrium, which emit high energy radiation by thermal Comptonization of soft photons. We find that the maximum luminosity to size ratio of the source (i.e. the compactness) depends not only on the…

Astrophysics · Physics 2009-10-22 Gabriele Ghisellini , Francesco Haardt

We report on the present status of our S5 polar cap phase-connected astrometry program. We observe 13 radio sources in the northernmost 20deg of the sky at the wavelengths of 3.6cm and 2cm, and we plan to extend the program to 0.7cm. We…

Astrophysics · Physics 2007-05-23 E. Ros , J. M. Marcaide , J. C. Guirado , M. A. Perez-Torres

Due to the large dynamic ranges involved with separating the cosmological 21-cm signal from the Cosmic Dawn from galactic foregrounds, a well-calibrated instrument is essential to avoid biases from instrumental systematics. In this paper we…

Astrometric calibration of images with a small field of view is often inferior to the internal accuracy of the source detections due to the small number of accessible guide stars. One important experiment with such challenges is the Hubble…

Instrumentation and Methods for Astrophysics · Physics 2019-11-06 Fan Tian , Tamás Budavári , Amitabh Basu , Stephen H. Lubow , Richard L. White

Radio synthesis imaging is dependent upon deconvolution algorithms to counteract the sparse sampling of the Fourier plane. These deconvolution algorithms find an estimate of the true sky brightness from the necessarily incomplete sampled…

Astrophysics · Physics 2009-11-13 T. J. Cornwell

Calibration is nowadays one of the most important processes involved in the extraction of valuable data from measurements. The current availability of an optimum data cube measured from a heterogeneous set of instruments and surveys relies…

Instrumentation and Methods for Astrophysics · Physics 2012-08-13 Maria Jose Marquez

Cataloging is challenging in crowded fields because sources are extremely covariant with their neighbors and blending makes even the number of sources ambiguous. We present the first optical probabilistic catalog, cataloging a crowded (~0.1…

Instrumentation and Methods for Astrophysics · Physics 2017-09-13 Stephen K. N. Portillo , Benjamin C. G. Lee , Tansu Daylan , Douglas P. Finkbeiner

Crossmatching catalogs at different wavelengths is a difficult problem in astronomy, especially when the objects are not point-like. At radio wavelengths an object can have several components corresponding, for example, to a core and lobes.…

Instrumentation and Methods for Astrophysics · Physics 2015-05-05 Dongwei Fan , Tamás Budavári , Ray P. Norris , Andrew M. Hopkins