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By utilizing the quadratic dependency of the interferometry phase on time, the Hannover Very Long Baseline Atom Interferometer facility (VLBAI) aims for sub nm/s$^2$ gravity measurement sensitivity. With its 10 m vertical baseline, VLBAI…

The planetary ephemeris is an essential tool for interplanetary spacecraft navigation, studies of solar system dynamics (including, for example, barycenter corrections for pulsar timing ephemeredes), the prediction of occultations, and…

Earth and Planetary Astrophysics · Physics 2015-05-20 D. L. Jones , E. Fomalont , V. Dhawan , J. Romney , W. M. Folkner , G. Lanyi , J. Border , R. Jacobson

Aims. We have analysed VLBA 92cm archive data of 44 extragalactic sources in order to identify early targets and potential calibrator sources for the LOFAR radio telescope and the RadioAstron space VLBI mission. Some of these sources will…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 H. Rampadarath , M. A. Garrett , A. Polatidis

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…

Astrophysics · Physics 2007-05-23 Eduardo Ros

Radio-loud active galactic nuclei (AGNs), hosting powerful relativistic jet outflows, provide an excellent laboratory for studying jet physics. Very long baseline interferometry (VLBI) enables high-resolution imaging on milli-arcsecond…

High Energy Astrophysical Phenomena · Physics 2018-02-07 X. -P. Cheng , T. An , X. -Y. Hong , J. Yang , P. Mohan , K. I. Kellermann , M. L. Lister , S. Frey , W. Zhao , Z. -L. Zhang , X. -C. Wu , X. -F. Li , Y. -K. Zhang

The Korean very-long-baseline interferometry (VLBI) network (KVN) and VLBI Exploration of Radio Astrometry (VERA) Array (KaVA) is the first international VLBI array dedicated to high-frequency (23 and 43 GHz bands) observations in East…

We present the principal astrometric results of the very-long-baseline interferometry (VLBI) program undertaken in support of the Gravity Probe B (GP-B) relativity mission. VLBI observations of the GP-B guide star, the RS CVn binary IM…

Instrumentation and Methods for Astrophysics · Physics 2015-06-04 M. I. Ratner , N. Bartel , M. F. Bietenholz , D. E. Lebach , J. -F. Lestrade , R. R. Ransom , I. I. Shapiro

Previous spectral energy distribution modeling based on XMM-Newton X-ray observation of the classical double-lobed radio galaxy 3C 411 left the possibility open for the presence of a blazar-like core. We investigated this scenario by…

Astrophysics of Galaxies · Physics 2019-03-13 Krisztina Perger , Sándor Frey , Krisztina Éva Gabányi

A patch of sky in the SDSS Stripe 82 was observed at 1.6 GHz with Very Long Baseline Interferometry (VLBI) using the European VLBI Network (EVN). The data were correlated at the EVN software correlator at JIVE (SFXC). There are fifteen…

Astrophysics of Galaxies · Physics 2014-06-19 H. -M. Cao , S. Frey , L. I. Gurvits , J. Yang , X. -Y. Hong , Z. Paragi , A. T. Deller , Ž. Ivezić

Aims. The phase scintillation of the European Space Agency's (ESA) Venus Express (VEX) spacecraft telemetry signal was observed at X-band (\lambda = 3.6 cm) with a number of radio telescopes of the European VLBI Network (EVN) in the period…

We present a comprehensive analysis of planetary phase variations, including possible planetary light offsets, using eighteen quarters of data from the Kepler space telescope. After correcting for systematics, we found fourteen systems with…

Earth and Planetary Astrophysics · Physics 2015-05-27 Lisa J. Esteves , Ernst J. W. De Mooij , Ray Jayawardhana

Very Long Baseline Interferometry (VLBI) offers unrivalled resolution in studies of celestial radio sources. The subjects of interest of the IAU Symposium No. 356, the Active Galactic Nuclei (AGN) of all types, constitute the major…

Instrumentation and Methods for Astrophysics · Physics 2021-02-03 Leonid I. Gurvits , Robert Beswick , Melvin Hoare , Ann Njeri , Jay Blanchard , Carla Sharpe , Adrian Tiplady , Aletha de Witt

We conducted very long baseline interferometry (VLBI) observations of five radio-loud narrow-line Seyfert 1 (NLS1) galaxies in milliarcsecond resolutions at 1.7 GHz (18 cm) using the Very Long Baseline Array (VLBA). Significant parsec-scale…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Akihiro Doi , Keiichi Asada , Hiroshi Nagai

Ever since the discovery by the Fermi mission that active galactic nuclei (AGN) produce copious amounts of high-energy emission, its origin has remained elusive. Using high-frequency radio interferometry (VLBI) polarization imaging, we…

High Energy Astrophysical Phenomena · Physics 2018-05-15 B. Rani , S. G. Jorstad , A. P. Marscher

We present High Sensitivity Array (HSA) and enhanced Multi Element Remotely Linked Interferometer Network (eMERLIN) observations of the radio-loud broad-lined type Ic supernova PTF11qcj obtained $\sim7.5$ years after the explosion. Previous…

High Energy Astrophysical Phenomena · Physics 2021-03-31 N. T. Palliyaguru , A. Corsi , M. Pérez-Torres , E. Varenius , H. Van Eerten

We have carried out full imaging simulation studies to explore the impact of frequency standards in millimeter and sub-millimeter Very Long Baseline Interferometry (VLBI), focusing on the coherence time and sensitivity. In particular, we…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 M. Rioja , R. Dodson , Y. Asaki , J. Hartnett , S. Tingay

As part of our ongoing search for technosignatures, we collected over three terabytes of data in May 2017 with the L-band receiver (1.15-1.73 GHz) of the 100 m diameter Green Bank Telescope. These observations focused primarily on planetary…

We report on an ongoing effort to image active galactic nuclei simultaneously observed at 2.3 and 8.6 GHz in the framework of a long-term VLBI project RDV (Research and Development - VLBA) started in 1994 aiming to observe compact…

Astrophysics · Physics 2008-12-31 A. B. Pushkarev , Y. Y. Kovalev

We present EVN observations of seven BL Lac objects selected from the RGB sample. To investigate the intrinsic radiation property of BL Lac objects, we estimated the Doppler factor with the VLA or MERLIN core and the total 408 MHz…

Astrophysics · Physics 2009-11-13 Zhongzu Wu , D. R. Jiang , Minfeng Gu , Yi Liu

We discuss the advantages which the next generation interferometer SKA (the Square Kilometer Array) will bring for Very Long Baseline Interferometry (VLBI) at centimeter wavelengths. With a sensitivity to micro-Jy level flux density, a…

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