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Differential phase observations with a near-IR interferometer offer a way to obtain spectra of extrasolar planets. The method makes use of the wavelength dependence of the interferometer phase of the planet/star system, which depends both…

Astrophysics · Physics 2015-06-24 Viki Joergens , Andreas Quirrenbach

Very long baseline interferometry (VLBI) provides the resolution needed to make precision measurements of a pulsar's parallax and proper motion. In making these measurements, the astronomer is faced with difficult calibration problems and a…

Astrophysics · Physics 2007-05-23 Walter Brisken

The VLTI Spectro Imager (VSI) was proposed as a second-generation instrument of the Very Large Telescope Interferometer providing the ESO community with spectrally-resolved, near-infrared images at angular resolutions down to 1.1…

The application of Very Long Baseline Interferometry (VLBI) to the Search for Extraterrestrial Intelligence (SETI) has been limited to date, despite the technique offering many advantages over traditional single-dish SETI observations. In…

We present the adaptive optics assisted, near-infrared VLTI instrument - GRAVITY - for precision narrow-angle astrometry and interferometric phase referenced imaging of faint objects. Precision astrometry and phase-referenced…

Since its observation in 2019, the first image of a super-massive black hole using Very Long Baseline Interferometry (VLBI) with an Earth-scale baseline has generated much scientific and public interest, including the possible extension of…

Instrumentation and Methods for Astrophysics · Physics 2026-05-08 Eric Burt , Todd Ely , Geoff Bower , Joe Lazio , Marin Anderson , Sonia Hernandez

Deep learning has revolutionized the field of hyperspectral image (HSI) analysis, enabling the extraction of complex spectral and spatial features. While convolutional neural networks (CNNs) have been the backbone of HSI classification,…

The rapidly rotating primary component of Regulus A system has been observed, for the first time, using the technique of differential interferometry at high spectral resolution. The observations have been performed across the Br$_\gamma$…

Solar and Stellar Astrophysics · Physics 2017-12-12 S. Jankov , M. Hadjara , R. G. Petrov , P. Cruzalèbes , A. Spang , S. Lagarde

We discuss the present performance and the future perspectives of VLBI in the 3 mm to 0.85 mm observing bands (so called mm-VLBI). The availability of new telescopes and the recent technical development towards larger observing bandwidth…

Astrophysics · Physics 2008-12-23 T. P. Krichbaum , U. Bach , D. A. Graham , W. Alef , A. Roy , A. Witzel , J. A. Zensus , M. Bremer , S. Sanchez

Very-long-baseline interferometry (VLBI) is a challenging observational technique, which requires in-depth knowledge about radio telescope instrumentation, interferometry, and the handling of noisy data. The reduction of the raw data is…

Instrumentation and Methods for Astrophysics · Physics 2022-09-14 Michael Janssen , Jack F. Radcliffe , Jan Wagner

VLBI at millimeter wavelengths (mm-VLBI) allows the detailed imaging of compact galactic and extragalactic radio sources with micro-arcsecond scale resolution, unaccessible by other observing techniques. Here we discuss the scientific…

Astrophysics · Physics 2007-05-23 T. P Krichbaum , A. Witzel , J. A. Zensus

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

We describe a new method which achieves high precision Very Long Baseline Interferometry (VLBI) astrometry in observations at millimeter wavelengths. It combines fast frequency-switching observations, to correct for the dominant…

Instrumentation and Methods for Astrophysics · Physics 2015-05-27 Maria J. Rioja , Richard Dodson

We present the proposal for the infrared adaptive optics (AO) assisted, two-object, high-throughput, multiple-beam-combiner GRAVITY for the VLTI. This instrument will be optimized for phase-referenced interferometric imaging and…

Astrophysics · Physics 2007-05-23 F. Eisenhauer , G. Perrin , S. Rabien , A. Eckart , P. Lena , R. Genzel , R. Abuter , T. Paumard , W. Brandner

This manual is intended to help ALMA and other interferometer users improve images by recognising limitations and how to overcome them and deciding when and how to use self-calibration. The images provided by the ALMA Science Archive are…

Instrumentation and Methods for Astrophysics · Physics 2022-07-13 A. M. S. Richards , E. Moravec , S. Etoka , E. B. Fomalont , A. F. Pérez-Sánchez , M. C. Toribio , R. A. Laing

We discuss the technique of Wide-field imaging as it applies to Very Long Baseline Interferometry (VLBI). In the past VLBI data sets were usually averaged so severely that the field-of-view was typically restricted to regions extending a…

Astrophysics · Physics 2009-10-31 M. A. Garrett , R. W. Porcas , A. Pedlar , T. W. B. Muxlow , S. T. Garrington

Exploring the use of single-mode fibers (SMFs) in high precision Doppler spectrometers has become increasingly attractive since the advent of diffraction-limited adaptive optics systems on large-aperture telescopes. Spectrometers fed with…

Instrumentation and Methods for Astrophysics · Physics 2015-12-02 Samuel Halverson , Arpita Roy , Suvrath Mahadevan , Christian Schwab

The Very Large Telescope Interferometer is one of the most proficient observatories in the world for high angular resolution. Since its first observations, it has hosted several interferometric instruments operating in various bandwidths in…

There are several solutions to code the signal arising from optical long baseline multi-aperture interferometers. In this paper,we focus on the {\bf non homothetic spatial coding scheme} (multiaxial) with the fringe pattern coded along one…

Astrophysics · Physics 2009-11-11 E. Tatulli , J. -B. LeBouquin

In this paper we describe a new approach for mm-VLBI calibration that provides bona-fide astrometric alignment of the mm-wavelength images from a single source, for the measurement of frequency dependent effects, such as `core-shifts' near…

Instrumentation and Methods for Astrophysics · Physics 2017-01-18 Richard Dodson , María Rioja , Sol Molina , José-Luis Gómez