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We present the analysis of four 3.6 cm radio continuum archival observations of Orion obtained using the Very Large Array in its A-configuration, with $0\rlap.{''}3$ angular resolution. The observations were made during the period…

Astrophysics · Physics 2009-11-10 Luis A. Zapata , Luis F. Rodriguez , Stanley E. Kurtz , C. R. O'Dell

The advent of next-generation telescope facilities brings with it an unprecedented amount of data, and the demand for effective tools to process and classify this information has become increasingly important. This work proposes a novel…

In order to obtain more comprehensive information about an celestial object, the radio image must be identified with the optical one. Many years the identification process is carried out with the coordinate coincidence criteria, which leads…

Astrophysics · Physics 2007-05-23 A. Lipovka , N. Lipovka

We present an all-sky catalog of absolute positions and estimates of correlated flux density of 21,942 compact radio sources determined from processing interferometric visibility data of virtually all very long baseline interferometry…

Instrumentation and Methods for Astrophysics · Physics 2025-01-20 Leonid Petrov , Yuri Y. Kovalev

The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8 Ms, Chandra program that has imaged the central 0.9 deg^2 of the COSMOS field down to limiting depths of 1.9 10^-16 erg cm^-2 s-1 in the 0.5-2 keV band, 7.3 10^-16 erg cm^-2 s^-1 in the…

In this pilot investigation, precise optical positions in the FK5 system are presented for a set of 16 compact extragalactic radio sources, which will be part of the future radio--optical reference frame. The 0.9 m KPNO and CTIO telescopes…

Astrophysics · Physics 2009-10-28 N. Zacharias , C. de Vegt , L. Winter , K. J. Johnston

The polarization properties of radio sources at very low frequencies (<200 MHz) have not been widely measured, but the new generation of low-frequency radio telescopes, including the Low Frequency Array (LOFAR: a Square Kilometre Array Low…

The goals of this work are to provide NIR polarimetry of the stellar sources in the central pc at the resolution of an 8m telescope for the first time, along with new insights into the nature of the known bright bow-shock sources. We use AO…

Astrophysics of Galaxies · Physics 2015-05-28 Rainer M. Buchholz , Gunther Witzel , Rainer Schödel , Andreas Eckart , Markus Bremer , Koraljka Muzic

The goal of this presentation is to report the latest progress in creation of the next generation of VLBI-based International Celestial Reference Frame, ICRF3. Two main directions of ICRF3 development are improvement of the S/X-band frame…

Instrumentation and Methods for Astrophysics · Physics 2015-11-26 Z. Malkin , C. S. Jacobs , F. Arias , D. Boboltz , J. Boehm , S. Bolotin , G. Bourda , P. Charlot , A. De Witt , A. Fey , R. Gaume , R. Heinkelmann , S. Lambert , C. Ma , A. Nothnagel , M. Seitz , D. Gordon , E. Skurikhina , J. Souchay , O. Titov

OSIRIS (Optical System for Imaging and low Resolution Integrated Spectroscopy) is the first light instrument of the Gran Telescopio Canarias (GTC). It provides a flexible and competitive tunable filter (TF). Since it is based on a…

A new sample of radio sources, with the designated name CENSORS (A Combined EIS-NVSS Survey Of Radio Sources), has been defined by combining the NRAO VLA Sky Survey (NVSS) at 1.4 GHz with the ESO Imaging Survey (EIS) Patch D, a 3 by 2…

Astrophysics · Physics 2009-11-10 P. N. Best , J. N. Arts , H. J. A. Rottgering , R. Rengelink , M. H. Brookes , J. Wall

Aligning generative real-world image super-resolution models with human visual preference is challenging due to the perception--fidelity trade-off and diverse, unknown degradations. Prior approaches rely on offline preference optimization…

Computer Vision and Pattern Recognition · Computer Science 2026-03-16 Shijie Zhao , Xuanyu Zhang , Bin Chen , Weiqi Li , Qunliang Xing , Kexin Zhang , Yan Wang , Junlin Li , Li Zhang , Jian Zhang , Tianfan Xue

Measuring the alignment of polarized radio sources requires comparing vectors at different locations on the sky, i.e. on a sphere. A test of alignment is derived herein. While both large scale and coordinate independent, the test avoids the…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-13 Richard Shurtleff

The Low Frequency Array (LOFAR) Two-metre Sky Survey (LoTSS) is a sensitive, high-resolution 120-168 MHz survey split across multiple tiers over the northern sky. The first LoTSS Deep Fields data release consists of deep radio continuum…

An all-sky comprehensive catalog of calculated radio and X-ray associations to optical objects is presented. Included are X-ray sources from XMM-Newton, Chandra and ROSAT catalogs, radio sources from NVSS, FIRST and SUMSS catalogs, and…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Eric Flesch

Very long baseline interferometry (VLBI) technique allows us to determine positions of thousands of radio sources using the absolute astrometry approach. I have investigated the impact of a selection of observing frequencies in a range from…

Instrumentation and Methods for Astrophysics · Physics 2024-05-14 Leonid Petrov

Abridged : The various IBIS/ISGRI catalogues contain a large population of hard X-ray sources whose nature is still unknown. Even if the $>20$ keV positional uncertainty provided by ISGRI is unprecedented, it is still too large to pinpoint…

High Energy Astrophysical Phenomena · Physics 2015-05-18 Jerome Rodriguez , John A. Tomsick , Arash Bodaghee

Previous studies based on the latest realisation of the International Celestial Reference Frame (ICRF3) have suggested a correlation between astrometric properties (such as the radio-optical offset) and redshift for active galactic nuclei…

Instrumentation and Methods for Astrophysics · Physics 2026-04-01 Zhiyun Zhang , N. Liu , Xiaxuan Zhang , I. Nurul Huda , Sufen Guo , Z. Zhu , J. -C. Liu , J. Yao , Z. -W. Wang , H. -F. Yu , D. -D. Zhang

We present a catalogue of optical and near-infrared counterparts to radio sources detected in the Euclid Deep Field North (EDF-N) using observations from the LOw-Frequency ARray (LOFAR) High Band Antenna (HBA) at 144 MHz with 6 arcsec…

LARS is an Absolute Reference Spectrograph designed for ultra-precise solar observations. The high-resolution echelle spectrograph of the Vacuum Tower Telescope is supported by a state-of-the-art laser frequency comb to calibrate the solar…

Instrumentation and Methods for Astrophysics · Physics 2017-11-01 J. Loehner-Boettcher , W. Schmidt , H. -P. Doerr , T. Kentischer , T. Steinmetz , R. A. Probst , R. Holzwarth
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