相关论文: Multifrequency Method for Mapping Active Galactic …

Multi-frequency Very Long Baseline Array (VLBA) polarimetry observation of the GHz-Peaked Spectrum (GPS) quasar OQ172 (J1445+0958) has been performed at 1.6, 2.2, 4.8, 8.3 and 15.3 GHz in 2005. Core-jet structures are detected in all bands…

The space astrometry mission GAIA will construct a dense optical QSO-based celestial reference frame. For consistency between optical and radio positions, it will be important to align the GAIA frame and the International Celestial…

The analysis of current Cosmic Microwave Background (CMB) experiments is based on the interpretation of multi-frequency sky maps in terms of different astrophysical components and it requires specifically tailored component separation…

We propose a new approach for the accurate reconstruction of cosmic microwave background distributions from observations containing in addition to the primary fluctuations the radiation from unresolved extragalactic point sources and pixel…

Hyperspectral imaging has become a significant source of valuable data for astronomers over the past decades. Current instrumental and observing time constraints allow direct acquisition of multispectral images, with high spatial but low…

Aims : We describe MS-MFS, a multi-scale multi-frequency deconvolution algorithm for wide-band synthesis-imaging, and present imaging results that illustrate the capabilities of the algorithm and the conditions under which it is feasible…

A catalog containing milliarcsecond--accurate positions of 1332 extragalactic radio sources distributed over the northern sky is presented - the Very Long Baseline Array Calibrator Survey (VCS1). The positions have been derived from…

The radio continuum emission from the Galaxy has a rich mix of thermal and non-thermal emission. This very richness makes their interpretation challenging since the low radio opacity means that a radio image represents the sum of all…

High-resolution radio observations are ideal for constraining the value of physical parameters in the inner regions of active-galactic-nucleus jets and complement results on multiwavelength (MWL) observations. This study is part of a wider…

This document describes the advantages of applying "Source/Frequency Phase Referencing" (SFPR) techniques to the analysis of VLBI observations with VSOP-2, for high precision astrometric measurements and/or increased sensitivity. The SFPR…

Spectral variability in hyperspectral images can result from factors including environmental, illumination, atmospheric and temporal changes. Its occurrence may lead to the propagation of significant estimation errors in the unmixing…

By linking widely separated radio dishes, the technique of very long baseline interferometry (VLBI) can greatly enhance angular resolution in radio astronomy. However, at any given moment, a VLBI array only sparsely samples the information…

We present Fermi-LAT and multi-frequency, multi-epoch VLBA data for the TeV blazar Mrk421. We collected the data during a long and intensive multi-frequency campaign in 2011. We study the gamma-ray light curve, the photon index evolution…

We present a new technique for obtaining model fittings to VLBI images of astrophysical jets. The method minimizes a performance function proportional to the sum of the squared difference between the model and observed images. The model…

We present simulated images of Supernova 1993J at 8.4 GHz using Very Long Baseline Interferometry (VLBI) techniques. A spherically symmetric source model is convolved with realistic uv-plane distributions, together with standard imaging…

While conventional imaging in VLBI provides information only about the relative position between different features of a given source, phase-referenced observations can provide precise positional information with respect to an external…

With the establishment of the AUT University 12m radio telescope at Warkworth, New Zealand has now become a part of the international Very Long Baseline Interferometry (VLBI) community. A major product of VLBI observations are images in the…

We are using the NRAO VLBA at 5.0 GHz to image about 200 FIRST sources stronger than 10 mJy at 1.4 GHz in the NDWFS.

Image reconstruction in very-long baseline interferometry operates under severely sparse aperture coverage with calibration challenges from both the participating instruments and propagation medium, which introduce the risk of biases and…

Many low-luminosity active galactic nuclei (AGNs) contain a compact radio core which can be observed with high angular resolution using very long baseline interferometry (VLBI). Combining arcsec-scale structural information with…