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Imaging algorithms form powerful analysis tools for VLBI data analysis. However, these tools cannot measure certain image features (e.g., ring diameter) by their non-parametric nature. This is unfortunate since these image features are…

Instrumentation and Methods for Astrophysics · Physics 2024-07-12 Paul Tiede , Avery E. Broderick , Daniel C. M. Palumbo

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) In a series of publications, we describe a comprehensive comparison of Event Horizon Telescope (EHT) data with theoretical models of Sgr A* and M87*. Here, we report on improvements made to our observational data reduction…

Instrumentation and Methods for Astrophysics · Physics 2025-06-18 M. Janssen , C. -k. Chan , J. Davelaar , I. Natarajan , H. Olivares , B. Ripperda , J. Röder , M. Rynge , M. Wielgus

Extracting polarimetric information from very long baseline interferometry (VLBI) data is demanding but vital for understanding the synchrotron radiation process and the magnetic fields of celestial objects, such as active galactic nuclei…

Instrumentation and Methods for Astrophysics · Physics 2025-11-21 Jong-Seo Kim , Jakob Roth , Jongho Park , Jack D. Livingston , Philipp Arras , Torsten A. Enßlin , Michael Janssen , J. Anton Zensus , Andrei P. Lobanov

We present a multi-calibrator solution, i.e. MultiView, to achieve accurate astrometry on the level of the thermal noise at low VLBI frequencies dominated by ionospheric residuals. We demonstrate on L-band VLBA observations how MultiView…

Instrumentation and Methods for Astrophysics · Physics 2018-04-10 Gabor Orosz , Maria J. Rioja , Richard Dodson , Hiroshi Imai , Sandor Frey

We have assessed accuracy of estimates of Earth orientation parameters (EOP) determined from several very long baseline interferometry (VLBI) observing programs that ran concurrently at different networks. We consider that the root mean…

Geophysics · Physics 2026-03-09 Leonid Petrov , Christian Ploetz , Matthias Schartner

Very Long Baseline Interferometry (VLBI) at radio wavelengths can provide astrometry accurate to 10 micro-arcseconds or better (i.e. better than the target GAIA accuracy) without being limited by dust obscuration. This means that unlike…

The ESO Very Large Telescope Interferometer (VLTI) is one of the leading interferometric facilities. It is equipped with several 8.2 and 1.8m telescopes, a large number of baselines up to 200m, and with several subsystems designed to enable…

Astrophysics · Physics 2009-11-10 A. Richichi , I. Percheron

The Effelsberg-Bonn HI Survey (EBHIS) covers the whole sky north of Dec(2000) = -5 deg. on a fully sampled angular grid. Using state-of-the-art FPGA-spectrometers we perform a Milky Way and an extragalactic HI survey in parallel. Moreover,…

Astrophysics of Galaxies · Physics 2014-11-20 J. Kerp , B. Winkel , P. M. W. Kalberla

We have developed a 230 and 345 GHz very-long-baseline interferometry (VLBI) receiver for the South Pole Telescope (SPT). With the receiver installed, the SPT has joined the global Event Horizon Telescope (EHT) array. The receiver optics…

Instrumentation and Methods for Astrophysics · Physics 2018-09-25 Junhan Kim , Daniel P. Marrone

Space Very Long Baseline Interferometry is a radio astronomy technique distinguished by a record-high angular resolution reaching single-digit microseconds of arc. The paper provides a brief account of the history of developments of this…

Instrumentation and Methods for Astrophysics · Physics 2023-12-27 Leonid I. Gurvits

The newly installed Silmaril beam combiner at the CHARA array is designed to observe previously inaccessible faint targets, including Active Galactic Nuclei and T-Tauri Young Stellar Objects. Silmaril leverages cutting-edge optical design,…

We present a new open-source data-reduction pipeline to reconstruct spectral data cubes from raw SPHERE integral-field spectrograph (IFS) data. The pipeline is written in Python and based on the pipeline that was developed for the CHARIS…

Earth and Planetary Astrophysics · Physics 2022-12-14 Matthias Samland , Timothy Brandt , Julien Milli , Philippe Delorme , Arthur Vigan

The concept of a new space very long baseline interferometry system named the Event Horizon Imager (EHI) has been proposed to dramatically improve black hole imaging and provide precise tests of the theory of general relativity. We…

High Energy Astrophysical Phenomena · Physics 2026-02-04 Anastasia Shlentsova , Freek Roelofs , Sara Issaoun , Jordy Davelaar , Heino Falcke

The introduction of infrared arrays for lunar occultations (LO) work and the improvement of predictions based on new deep IR catalogues have resulted in a large increase in the number of observable occultations. We provide the means for an…

Astrophysics · Physics 2014-11-18 O. Fors , A. Richichi , X. Otazu , J. Nunez

Since October 1, 2006, spectroscopic data from the two FORS instruments have been reduced with a new pipeline, which is based on a bottom-up calibration approach. I give a short description of the pipeline and discuss first experiences with…

Astrophysics · Physics 2015-05-13 S. Moehler

High-resolution astronomical imaging at sub-GHz radio frequencies has been available for more than 15 years, with the VLA at 74 and 330 MHz, and the GMRT at 150, 240, 330 and 610 MHz. Recent developments include wide-bandwidth upgrades for…

Instrumentation and Methods for Astrophysics · Physics 2014-02-21 H. T. Intema

We present flame, a pipeline for reducing spectroscopic observations obtained with multi-slit near-infrared and optical instruments. Because of its flexible design, flame can be easily applied to data obtained with a wide variety of…

Instrumentation and Methods for Astrophysics · Physics 2018-06-29 Sirio Belli , Alessandra Contursi , Richard I. Davies

One of the most important changes in observational astronomy of the 21st Century is a rapid shift from classical object-by-object observations to extensive automatic surveys. As CCD detectors are getting better and their prices are getting…

Astrophysics · Physics 2009-11-13 Andrej Prsa , Tomaz Zwitter
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