Results 71 to 80 of about 909 (203)

Not So Fast: A New Catalog of Meteor Persistent Trains

Journal of Geophysical Research: Space Physics, Volume 129, Issue 7, July 2024.
Abstract This paper presents the results of a nearly 2‐year long campaign to detect and analyze meteor persistent trains (PTs)—self‐emitting phenomena which can linger up to an hour after their parent meteor. The modern understanding of PTs has been primarily developed from the Leonid storms at the turn of the century; our goal was to assess the ...
L. E. Cordonnier, K. S. Obenberger, J. M. Holmes, G. B. Taylor, D. Vida   +4 more
wiley   +1 more source

An Unusual Pulse Shape Change Event in PSR J1713+0747 Observed with the Green Bank Telescope and CHIME

The Astrophysical Journal
The millisecond pulsar J1713+0747 underwent a sudden and significant pulse shape change between 2021 April 16 and 17 (MJDs 59320 and 59321). Subsequently, the pulse shape gradually recovered over the course of several months.
Ross J. Jennings, James M. Cordes, Shami Chatterjee, Maura A. McLaughlin, Paul B. Demorest, Zaven Arzoumanian, Paul T. Baker, Harsha Blumer, Paul R. Brook, Tyler Cohen, Fronefield Crawford, H. Thankful Cromartie, Megan E. DeCesar, Timothy Dolch, Elizabeth C. Ferrara, Emmanuel Fonseca, Deborah C. Good, Jeffrey S. Hazboun, Megan L. Jones, David L. Kaplan, Michael T. Lam, T. Joseph W. Lazio, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, James W. McKee, Dustin R. Madison, Bradley W. Meyers, Chiara M. F. Mingarelli, David J. Nice, Timothy T. Pennucci, Benetge B. P. Perera, Nihan S. Pol, Scott M. Ransom, Paul S. Ray, Brent J. Shapiro-Albert, Xavier Siemens, Ingrid H. Stairs, Daniel R. Stinebring, Joseph K. Swiggum, Chia Min Tan, Stephen R. Taylor, Sarah J. Vigeland, Caitlin A. Witt   +43 more
doaj   +1 more source

The fireball of November 24, 1970, as the most probable source of the Ischgl meteorite

Meteoritics &Planetary Science, Volume 59, Issue 7, Page 1658-1691, July 2024.
Abstract The discovery of the Ischgl meteorite unfolded in a captivating manner. In June 1976, a pristine meteorite stone weighing approximately 1 kg, fully covered with a fresh black fusion crust, was collected on a mountain road in the high‐altitude Alpine environment.
Maria Gritsevich, Jarmo Moilanen, Jaakko Visuri, Matthias M. M. Meier, Colin Maden, Jürgen Oberst, Dieter Heinlein, Joachim Flohrer, Alberto J. Castro‐Tirado, Jorge Delgado‐García, Christian Koeberl, Ludovic Ferrière, Franz Brandstätter, Pavel P. Povinec, Ivan Sýkora, Florian Schweidler   +15 more
wiley   +1 more source

Cross‐Polarization Gain Calibration of Linearly Polarized VLBI Antennas by Observations of 4C 39.25

Radio Science, Volume 59, Issue 4, April 2024.
Abstract Radio telescopes with dual linearly polarized feeds regularly participate in Very Long Baseline Interferometry. One example is the VLBI Global Observing System (VGOS), which is employed for high‐precision geodesy and astrometry. In order to achieve the maximum signal‐to‐noise ratio, the visibilities of all four polarization products are ...
F. Jaron, I. Martí‐Vidal, M. Schartner, J. González‐García, E. Albentosa‐Ruiz, S. Bernhart, J. Böhm, J. Gruber, S. Modiri, A. Nothnagel, V. Pérez‐Díez, T. Savolainen, B. Soja, E. Varenius, M. H. Xu   +14 more
wiley   +1 more source

Synthesis Imaging with a Lunar Orbit Array. II. Impacts of Instrument-induced Phase Errors

The Astronomical Journal
A lunar orbit interferometer array suffers from a number of systematics. Beyond systematics induced by the imaging algorithm itself and thermal noise considered in F.
Meng Zhou, Furen Deng, Yidong Xu, Li Zhou, Xuelei Chen   +4 more
doaj   +1 more source

Prototype System for Unmanned Reference Point Determination at the Sub‐Millimeter Level

Earth and Space Science, Volume 11, Issue 2, February 2024.
Abstract The determination of reference points for telescopes is crucial for obtaining the local‐tie vector for a multi‐technology co‐located station. Traditional methods suffer from labor‐intensive fieldwork, long execution cycles, and systematic errors due to the incident angle of the total station's laser beam on the prism. In this paper, we propose
Zhibin Zhang, Zhikang Wang, Xiaohui Ma, Zhengxiong Sun, Dezhen Xu, Chengli Huang, Guangli Wang, Zhaoxiang Qi   +7 more
wiley   +1 more source

Validating the bright Gaia celestial reference frame with new VLBI astrometry of radio stars

Aims. There exist inconsistencies between the bright and faint Gaia Celestial Reference Frame 3 (Gaia-CRF3), which manifests as a systematic rotation and needs to be independently estimated then corrected in future data releases. Methods. We collected 64
Shuangjing Xu, Xiaofeng Mai, Bo Zhang, Jingdong Zhang   +3 more
core   +1 more source

Infrared-radio-follow-up observations for detection of the magnetic radio emission of extra solar planets: a new window to detect exoplanets

Frontiers in Astronomy and Space Sciences
There are several methods for indirectly detecting exoplanets, such as transit, radial velocity, astrometry, and the conventional gravitational microlensing approach.
Fatemeh Bagheri, Fatemeh Bagheri, Ramon E. Lopez, Amir Shahmoradi, Amir Shahmoradi   +4 more
doaj   +1 more source

Serial MultiView: An Efficient Approach to Mitigating Atmospheric Spatial-structure Errors for Very-long-baseline-interferometry Astrometry

The Astronomical Journal
Atmospheric propagation errors are a main constraint on the accuracy of very-long-baseline-interferometry astrometry. For relative astrometry, differential techniques can mitigate these errors, but their effectiveness diminishes with decreasing elevation
Jingdong Zhang, Bo Zhang, Shuangjing Xu, Maria J. Rioja, Richard Dodson, Xiaofeng Mai, Oleg Titov   +6 more
doaj   +1 more source

Ultra-precise astrometry with the next generation of radio instruments

, 2022
We are at the cusp of a generational shift in the power of radio interferometers, with both the SKA and ngVLA planning for exciting new and powerful instruments. These will be used in conjunction with other radio telescopes to provide VLBI with an order of magnitude greater sensitivity.
Dodson, Richard, Rioja, Maria
openaire   +2 more sources