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Aims: We study the characteristics of intermediate drift bursts (fibers) embedded in the July 14, 2000 large solar event. Methods: We used dynamic spectra from the acousto-optic analyzer (SAO) of the ARTEMIS-JLS solar radiospectrograph, in…

Solar and Stellar Astrophysics · Physics 2019-07-31 C. E. Alissandrakis , C. Bouratzis , A. Hillaris

Narrow band bursts appear on dynamic spectra from microwave to decametric frequencies as fine structures with very small duration and bandwidth. They are thought to mark small scale magnetic reconnection. We analyzed 27 metric type-IV…

Solar and Stellar Astrophysics · Physics 2016-01-27 C. Bouratzis , A. Hillaris , C. E. Alissandrakis , P. Preka-Papadema , X. Moussas , C. Caroubalos , P. Tsitsipis , A. Kontogeorgos

Fine structures embedded in type-IV burst continua may be used as diagnostics of the magnetic field restructuring and the corresponding energy release associated with the low corona development of flare/CME events. A catalog of 36 type-IV…

Solar and Stellar Astrophysics · Physics 2016-04-27 C. Bouratzis , A. Hillaris , C. E. Alissandrakis , P. Preka-Papadema , X. Moussas , C. Caroubalos , P. Tsitsipis , A. Kontogeorgos

Aims. We examine high time resolution dynamic spectra for fine structures in type II solar radio bursts Methods. We used data obtained with the (SAO) receiver of the Artemis-JLS (ARTEMIS-IV) solar radio spectrograph in the 450-270 MHz range…

Solar and Stellar Astrophysics · Physics 2019-04-17 S. Armatas , C. Bouratzis , A. Hillaris , C. E. Alissandrakis , P. Preka-Papadema , X. Moussas , E. Mitsakou , P. Tsitsipis , A. Kontogeorgos

We present the first results of an ongoing intra-day variability (IDV) flux density monitoring program of 107 blazars, which were selected from a sample of RadioAstron space very long baseline interferometry (VLBI) targets. The~IDV…

Intrinsic localized modes (ILMs) in a quasi-1D antiferromagnetic material (C2H5NH3)2CuCl4 are counted by using a novel nonlinear energy magnetometer. The ILMs are produced by driving the uniform spin wave mode unstable with an intense…

Pattern Formation and Solitons · Physics 2009-11-11 M. Sato , A. J. Sievers

Diffuse interstellar bands (DIBs) can trace different conditions of the ISM along the sightline toward the observed stars. A small survey was made in optical wavelengths, producing high resolution and high signal to noise spectra. We…

Astrophysics of Galaxies · Physics 2015-06-16 J. Kos , T. Zwitter

Drift pairs are an unusual type of fine structure sometimes observed in dynamic spectra of solar radio emission. They appear as two identical short narrowband drifting stripes separated in time; both positive and negative frequency drifts…

Solar and Stellar Astrophysics · Physics 2019-10-23 Alexey Kuznetsov , Eduard Kontar

Diffuse interstellar bands comprise hundreds of absorption features in the ISM. Most DIBs are observed in the optical, but some are in the IR. We observed 76 early-type stars at R=50,000 and S/N ratios of several hundreds using CRIRES. We…

Fiber bursts are a type of fine structure that is often superposed on type IV radio continuum emission during solar flares. Although studied for many decades, its physical exciter, emission mechanism, and association with the flare energy…

Solar and Stellar Astrophysics · Physics 2017-10-25 Zhitao Wang , Bin Chen , Dale E. Gary

The high temporal, spatial and spectral resolution of Interface Region Imaging Spectrograph (IRIS) has provided new insights into the understanding of different small-scale processes occurring at the chromospheric and transition region (TR)…

Solar and Stellar Astrophysics · Physics 2019-05-03 Nancy Narang , Vaibhav Pant , Dipankar Banerjee , Tom Van Doorsselaere

Intermediate mass stars (IMSs) represent the link between low-mass and high-mass stars and cover a key mass range for giant planet formation. In this paper, we present a spectroscopic survey of 241 young IMS candidates with IR-excess, the…

We calculate the emission line spectrum produced by the debris released when a white dwarf (WD) is tidally disrupted by an intermediate-mass black hole (IMBH; $M\sim 10^{2}-10^{5}\msun$) and we explore the possibility of using the emission…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Drew Clausen , Michael Eracleous

Approximately 0.01 % of all Si IV 1394 A spectra sampled in 2013 and 2014 by the Interface Region Imaging Spectrograph (IRIS) have IRIS burst profiles. However, these events are not evenly distributed across datasets with 19.31 % of these…

Solar and Stellar Astrophysics · Physics 2022-12-14 C. J. Nelson , L. Kleint

Using a new type of oscillation map, made from the radio spectra by the wavelet technique, we study the 18 April 2014 M7.3 flare (SOL2014-04-18T13:03:00L245C017). We find a quasi-periodic character of this flare with periods in the range…

Solar and Stellar Astrophysics · Physics 2017-07-19 M. Karlicky , J. Rybak , C. Monstein

We study the characteristics of moving type IV radio bursts which extend to the hectometric wavelengths (interplanetary type IV or type IV IP bursts) and their relationship with energetic phenomena on the Sun. Our dataset comprises 48…

Solar and Stellar Astrophysics · Physics 2016-06-28 Alexander Hillaris , Constantine Bouratzis , Alexander Nindos

Diffuse interstellar bands (DIBs) are broad absorption features measured in sightlines probing the diffuse interstellar medium. Although large carbon-bearing molecules have been proposed as the carriers producing DIBs, their identity…

Astrophysics of Galaxies · Physics 2018-12-05 M. C. Ramírez-Tannus , N. L. J. Cox , L. Kaper , A. de Koter

We report the properties of more than 600 bursts (including cluster-bursts) detected from the repeating fast radio burst (FRB) source FRB 20201124A with the Five-hundred-meter Aperture Spherical radio Telescope (FAST) during an extremely…

High Energy Astrophysical Phenomena · Physics 2023-01-04 D. J. Zhou , J. L. Han , B. Zhang , K. J. Lee , W. W. Zhu , D. Li , W. C. Jing , W. -Y. Wang , Y. K. Zhang , J. C. Jiang , J. R. Niu , R. Luo , H. Xu , C. F. Zhang , B. J. Wang , J. W. Xu , P. Wang , Z. L. Yang , Y. Feng

We have studied a sample of 415 associated (z_ab z_em; relative velocity with respect to QSO <3000km/s) Mg II absorption systems with 1.0<=z_ab<=1.86, in the spectra of SDSS DR3 QSOs, to determine the dust content and ionization state in…

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