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相关论文: 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…

天体物理仪器与方法 · 物理学 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…

天体物理学 · 物理学 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…

广义相对论与量子宇宙学 · 物理学 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…

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…

宇宙学与河外天体物理 · 物理学 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…

天体物理仪器与方法 · 物理学 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…

高能天体物理现象 · 物理学 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…

星系天体物理 · 物理学 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…

统计计算 · 统计学 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…

天体物理仪器与方法 · 物理学 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…

宇宙学与河外天体物理 · 物理学 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…

天体物理学 · 物理学 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…

天体物理学 · 物理学 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…

天体物理仪器与方法 · 物理学 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…

天体物理学 · 物理学 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…

天体物理仪器与方法 · 物理学 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…

天体物理仪器与方法 · 物理学 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.…

天体物理仪器与方法 · 物理学 2015-05-05 Dongwei Fan , Tamás Budavári , Ray P. Norris , Andrew M. Hopkins