Results 41 to 50 of about 6,025 (156)

Interstellar Scintillation and Intraday Variability [PDF]

International Astronomical Union Colloquium, 1998
AbstractSources that are compact enough to show intrinsic variability on times of a day or less (IDV) at cm wavelengths must also show interstellar scintillation (ISS) on similar timescales. However for many IDV sources, the variations could be entirely due to ISS, reducing the implied brightness temperatures to ~ 1013 K or less.
openaire   +1 more source

Pulsar scintillation studies with LOFAR

Astronomy & Astrophysics
Context. The interstellar scintillation observed in radio pulsars arises from interference between electromagnetic waves scattered by electron density fluctuations in the turbulent interstellar plasma, providing a critical tool for probing the small ...
Cai Yanqing, Wu Ziwei, Zhu Weiwei, Verbiest Joris P. W., Liu Yulan, Moochickal Ambalappat Krishnakumar, Brüggen Marcus, Ciardi Benedetta, Dettmar Ralf-Jürgen, Fang Ziyao, Fu Qiuyang, Hoeft Matthias, Jin Jiawei, Künkel Lars, Künsemöller Jörn, Liu Caisong, Meng Lingqi, Miao Xueli, Niu Jiarui, Rejep Rukiya, Schwarz Dominik J., Shaifullah Golam M., Tiburzi Caterina, Vocks Christian, Wucknitz Olaf, Xue Mengyao, Yuan Mao, Yue Youling, Zhang Chunfeng, Zhang Zhen   +29 more
doaj   +1 more source

Using Giant Pulses to Measure the Impulse Response of the Interstellar Medium

The Astrophysical Journal, 2023
Giant pulses emitted by PSR B1937+21 are bright, intrinsically impulsive bursts. Thus, the observed signal from a giant pulse is a noisy but direct measurement of the impulse response from the ionized interstellar medium.
Nikhil Mahajan, Marten H. van Kerkwijk
doaj   +1 more source

On the role of stochastic Fermi acceleration in setting the dissipation scale of turbulence in the interstellar medium

, 2007
We consider the dissipation by Fermi acceleration of magnetosonic turbulence in the Reynolds Layer of the interstellar medium. The scale in the cascade at which electron acceleration via stochastic Fermi acceleration (STFA) becomes comparable to further ...
Achterberg, Armstrong, Blackman, Boldyrev, Boldyrev, Boldyrev, Boldyrev, Cho, Cho, Elmegreen, Eric G. Blackman, Fermi, Goldreich, Han, Haugen, Haugen, Haugen, LaRosa, Lithwick, Longair, Mac Low, Maron, Maron, Maron, Matthaeus, Minter, Minter, Molnar, Moran, Otte, Reynolds, Reynolds, Rickett, Robert Selkowitz, Schekochihin, Schekochihin, Selkowitz, Spangler, Spitzer, Vestuto   +39 more
core   +1 more source

Systematic and Stochastic Variations in Pulsar Dispersion Measures [PDF]

, 2016
We analyze deterministic and random temporal variations in dispersion measure (DM) from the full three-dimensional velocities of pulsars with respect to the solar system, combined with electron-density variations on a wide range of length scales ...
Armstrong, John W., Chatterjee, Shami, Cordes, James M., Jones, Megan L., Lam, Michael T., McLaughlin, Maura A.   +5 more
core   +3 more sources

A VLA Search for the Geminga Pulsar: A Bayesian Limit on a Scintillating Source [PDF]

, 1999
We derive an upper limit of 3 mJy (95% confidence) for the flux density at 317 MHz of the Geminga pulsar (J0633+1746). Our results are based on 7 hours of fast-sampled VLA data, which we averaged synchronously with the pulse period using a period model ...
Biggs J. D., D. A. Moffett, J. M. Cordes, Kuz’min A. D., Lorimer D. R., M. A. McLaughlin, Merck M., Ramachandran R., Spelstra T. A., T. H. Hankins   +9 more
core   +3 more sources

Influence of Mars Topography on Radiation Dose Detected by the Mars Science Laboratory and Assessment of Mars Surface Albedo Radiation

Journal of Geophysical Research: Planets, Volume 131, Issue 4, April 2026.
Abstract The Radiation Assessment Detector (RAD) on the Curiosity rover has been characterizing the Martian surface radiation field since 2012. The dose observed by RAD is influenced by a variety of factors, including an essential one, the terrain. After parking near Murray Buttes in September 2016 where it first detected a ∼5% decrease in dose rate ...
Jingnan Guo, Changqi Tian, Gabin Charpentier, Robert F. Wimmer‐Schweingruber, Salman Khaksarighiri, Lu Pan, Jan Leo Löwe, Bent Ehresmann, Donald M. Hassler, Cary Zeitlin, Daniel Matthiä, Thomas Berger, Günther Reitz   +12 more
wiley   +1 more source

Refractive scintillation in the interstellar medium

The Astrophysical Journal, 1987
It is shown here that the large-scale component of interstellar scintillation which causes the slow variation in the apparent intensity of pulsars on time scales of days to months can be greatly enhanced when the turbulence spectrum has a limiting inner scale of the order 10 to the 9th m.
W. A. Coles, B. J. Rickett, J. L. Codona, R. G. Frehlich   +3 more
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The ALPACA experiment: The project of the first sub-PeV gamma-ray observation in the southern sky

SciPost Physics Proceedings, 2023
The ALPACA experiment is a project aiming to observe sub-PeV gamma rays for the first time in the southern hemisphere. The main goal of ALPACA is to identify PeVatrons, the accelerators of Galactic PeV cosmic rays, by observing sub-PeV pion-decay gamma ...
Teruyoshi Kawashima for the ALPACA Collaboration
doaj   +1 more source

Broadband Meter-Wavelength Observations of Ionospheric Scintillation

, 2015
Intensity scintillations of cosmic radio sources are used to study astrophysical plasmas like the ionosphere, the solar wind, and the interstellar medium. Normally these observations are relatively narrow band. With Low Frequency Array (LOFAR) technology
Brentjens, M., Coles, W. A., de Reijer, J-P., Ebbendorf, N., Enell, C-F., Fallows, R. A., Gerbers, M., Grit, T., Gruppen, P., Iinatti, T., Kero, A., Lehtinen, M., McKay, D., Meulman, H., Norden, M., Orispää, M., Postila, M., Raita, T., Roininen, L., Schoenmakers, A., Stuurwold, K., Turunen, E., Ulich, Th., Vierinen, J., Virtanen, I. I.   +24 more
core   +1 more source