Results 51 to 60 of about 424 (141)

Deep Very Long Baseline Interferometry Constraints on Compact Radio Cores in Four Ultraluminous X-Ray Sources

The Astrophysical Journal
We present high-sensitivity very long baseline interferometry (VLBI) observations of four ultraluminous X-ray sources (ULXs): Holmberg II X-1, IC 342 X-1, NGC 6946 X-1, and NGC 925 X-1.
Ailing Wang, Hua Feng, Tao An, Yijia Zhang, Jun Yang, Roberto Soria, Lian Tao, Thomas Russell, Jing Guo, Liang Zhang   +9 more
doaj   +1 more source

Calibrating VLBI Polarization Data Using GPCAL. I. Frequency-dependent Calibration

The Astrophysical Journal, 2023
In this series of papers, we present new methods of frequency- and time-dependent instrumental polarization calibration for very long baseline interferometry (VLBI).
Jongho Park, Keiichi Asada, Do-Young Byun   +2 more
doaj   +1 more source

Studying the Inner Heliosphere Using Radio Signals Transmitted From Spacecraft Orbiting Mars

Space Weather, Volume 23, Issue 5, May 2025.
Abstract In this campaign, we used very long baseline interferometry (VLBI) radio telescopes to track the carrier radio signal transmitted from spacecraft orbiting Mars during the Mars solar conjunction. The campaign extended from September 6th $6\text{th}$ to November 6th $6\text{th}$ 2021 and targeted the Mars Express (MEX) and Tianwen‐1 (TIW ...
J. Edwards, G. Molera Calvés, P. Kummamuru, N. M. M. Said, M. Ma   +4 more
wiley   +1 more source

Preparation of the VIRAC Radio Telescope RT-32 for e-VLBI Observations

Open Astronomy, 2013
A fully steerable parabolic antenna RT-32 with the mirror diameter 32 m owned by the Ventspils International Radio Astronomy Centre (VIRAC) is available for fundamental and applied research in radio astronomy.
Skirmante K., Bezrukovs Vl., Jekabsons N., Shmeld I.   +3 more
doaj   +1 more source

3 mm GMVA Observations of Total and Polarized Emission from Blazar and Radio Galaxy Core Regions

Galaxies, 2017
We present total and linearly polarized 3 mm Global mm-VLBI Array (GMVA; mm-VLBI: Very Long Baseline Interferometry observations at millimetre wavelengths) images of a sample of blazars and radio galaxies from the VLBA-BU-BLAZAR 7 mm monitoring program ...
Carolina Casadio, Thomas P. Krichbaum, Alan P. Marscher, Svetlana G. Jorstad, José L. Gómez, Iván Agudo, Uwe Bach, Jae-Young Kim, Jeffrey A. Hodgson, Anton J. Zensus   +9 more
doaj   +1 more source

Role of Barystatic Sea Level Change in Global Mass Conservation and Its Excitation to Length‐Of‐Day Variations

Earth and Space Science, Volume 12, Issue 1, January 2025.
Abstract Barystatic sea level stores excess water mass from the atmosphere and land to maintain global mass conservations within the Earth system. Besides the secular contribution to global sea‐level rise, changes in barystatic sea level also play an important role in mass‐induced length‐of‐day (LOD) variations over a few years or shorter periods ...
Qiqi Shi, Yonghong Zhou, Cancan Xu, Xueqing Xu   +3 more
wiley   +1 more source

Short Baseline Observations at Geodetic Observatory Wettzell

Data, 2018
The Geodetic Observatory Wettzell (GOW), jointly operated by the Federal Agency for Cartography and Geodesy (BKG), Germany and the Technical University of Munich, Germany is equipped with three radio telescopes for Very Long Baseline Interferometry (VLBI)
Apurva Phogat, Gerhard Kronschnabl, Christian Plötz, Walter Schwarz, Torben Schüler   +4 more
doaj   +1 more source

Holocene Paleoenvironment Changes Near Lake Funazoko‐Ike, East Antarctica, Based on Analyses of Sediments and Microfossils

Island Arc, Volume 34, Issue 1, January/December 2025.
ABSTRACT Lake Funazoko‐Ike was formed by a relative sea level fall due to crustal uplift after the melting of the ice sheet. Today, the lake surface lies approximately 25 m below the present sea level. Evidence of these processes is recorded in sediments deposited from the sill to the lake surface around Lake Funazoko‐Ike during the middle to late ...
Satoshi Sasaki, Koji Seto, Kota Katsuki
wiley   +1 more source

A Satellite Drift Scan Approach for Establishing the Pointing Model of Radio Telescopes

Advances in Astronomy, Volume 2025, Issue 1, 2025.
In the era of large satellite constellations, there are more than 1000 satellites in orbit. While the signals from these satellites may pose a risk of radio frequency interference (RFI) to radio telescopes, they also present a potential advantage by serving as high‐spatial‐density pointing references for radio telescopes.
Ye Yuan, Zhi-Yong Liu, Na Wang, Hao Yan, Arpan Hazra   +4 more
wiley   +1 more source

A Global Combination of Geodetic Techniques at the Observation Level: New Perspectives on the Terrestrial Reference Frame

Journal of Geophysical Research: Solid Earth, Volume 129, Issue 12, December 2024.
Abstract We describe the development and assessment of a new terrestrial reference frame (TRF) based on a combination of geodetic techniques at the observation level over the period 2010–2022. Included in the solution are observations from the Global Positioning System (GPS), Satellite Laser Ranging (SLR) and Very Long Baseline Interferometry (VLBI). A
B. Haines, W. Bertiger, S. Desai, M. Ellmer, M. Heflin, D. Kuang, G. Lanyi, C. Naudet, A. Peidou, P. Ries, A. Sibois, X. Wu   +11 more
wiley   +1 more source