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In the modern Universe the existence of various forms of scalar fields is supposed. On the one hand these fields can explain recently discovered positive $\Lambda$-term(see e.g. Ref. \cite{ref:Sahni}), on the other hand its form cluster…

Astrophysics · Physics 2007-05-23 V. Folomeev , V. Gurovich , R. Usupov

It was found by Amati et al. in 2002 that for a small sample of 9 gamma-ray bursts, more distant events appear to be systematically harder in the soft gamma-ray band. Here, we have collected a larger sample of 65 gamma-ray bursts, whose…

High Energy Astrophysical Phenomena · Physics 2016-04-18 J. J. Geng , Y. F. Huang

We use spectropolarimetric observations of the Ca II 8542~\AA\ line, taken from the Swedish 1-m Solar Telescope (SST), in an attempt to recover dynamic activity in a micro-flaring region near a sunspot via inversions. These inversions show…

Solar and Stellar Astrophysics · Physics 2017-08-30 A. Reid , V. Henriques , M. Mathioudakis , J. G. Doyle , T. Ray

A multi-wavelength spatial and temporal analysis of solar high energy electrons is conducted using the August 20, 2002 flare of an unusually flat (gamma=1.8) hard X-ray spectrum. The flare is studied using RHESSI, Halpha, radio, TRACE, and…

Astrophysics · Physics 2008-11-26 J. Kasparova , M. Karlicky , E. P. Kontar , R. A. Schwartz , B. R. Dennis

We present a high spatial resolution Halpha survey of 23 cooling flow clusters using the Maryland Magellan Tunable Filter (MMTF), covering 1-2 orders of magnitude in cooling rate, dM/dt, temperature and entropy. We find 8/23 (35%) of our…

High Energy Astrophysical Phenomena · Physics 2015-05-19 Michael McDonald , Sylvain Veilleux , David S. N. Rupke , Richard Mushotzky

Gamma-ray bursts are still not fully understood events. However, their exploration could provide a useful tool for a better understanding of the early Universe because they belong to the most distant and violent objects that astronomers…

High Energy Astrophysical Phenomena · Physics 2011-05-13 Jakub Ripa

This is the last of a series of three papers in which we give a new, shorter proof of a slightly improved version of Almgren's partial regularity of area minimizing currents in Riemannian manifolds. Here we perform a blow-up analysis…

Differential Geometry · Mathematics 2015-10-01 Camillo De Lellis , Emanuele Spadaro

The discovery that the bolometric energetics (and/or peak luminosity) of Gamma Ray Bursts correlates with their spectral properties has allowed to standardize the burst energetics to such a degree to enable their use for constraining the…

Astrophysics · Physics 2007-06-01 Gabriele Ghisellini

We have performed 5 night spectroscopic observation of the Halpha line of EV Lac with a medium wavelength resolution (R~ 10,000) using the 2m Nayuta telescope at the Nishi-Harima Astronomical Observatory. EV Lac always possesses the Halpha…

Solar and Stellar Astrophysics · Physics 2018-05-30 Satoshi Honda , Yuta Notsu , Kosuke Namekata , Shota Notsu , Hiroyuki Maehara , Kai Ikuta , Daisaku Nogami , Kazunari Shibata

Recent observations in HL-2A tokamak give new experimental evidences of energetic particle mode (EPM) avalanche. In a strong EPM burst, the mode structure propagates radially outward within two hundred Alfv\'en time, while the frequency of…

We present centimeter-band total flux density and linear polarization light curves illustrating the signature of shocks during radio band outbursts associated in time with gamma-ray flares detected by the Fermi LAT. The general…

High Energy Astrophysical Phenomena · Physics 2011-11-01 M. F. Aller , P. A. Hughes , H. D. Aller , A. P. Marscher , S. G. Jorstad , T. Hovatta , M. C. Aller

Optical and near-UV continuum emissions in flares contribute substantially to flare energy budget. Two mechanisms play an important role for continuum emission in flares: hydrogen recombination after sudden ionization at chromospheric…

Solar and Stellar Astrophysics · Physics 2021-10-13 Reetika Joshi , Brigitte Schmieder , Petr Heinzel , James Tomin , Ramesh Chandra , Nicole Vilmer

We have calculated FeII emission line strengths for Active Galactic Nuclei Broad-Line Regions using precise radiative transfer and Iron Project atomic data. We improve the treatment of all previously considered excitation mechanisms for the…

Astrophysics · Physics 2009-10-30 T. A. A. Sigut , Anil K. Pradhan

We investigate the role of non-thermal electrons in the formation regions of Halpha, Hbeta, and Hgamma lines in order to unfold their influence on the formation of these lines. We concentrate on pulse-beam heating varying on a subsecond…

Solar and Stellar Astrophysics · Physics 2015-05-13 J. Kasparova , M. Varady , P. Heinzel , M. Karlicky , Z. Moravec

We review the imaging and spectroscopic properties of the Lyman alpha emission in starburst galaxies. The Lyman alpha photons escape is largely driven by kinematical and orientation effects related to the presence of large scale expanding…

Astrophysics · Physics 2007-05-23 Daniel Kunth , M. Hayes , G. Ostlin , J. M. Mas-Hesse , C. Leitherer , A. Petrosian

Radio frequency waves are routinely used in tokamak fusion plasmas for plasma heating, current control, and as well as in diagnostics. These waves are excited by antenna structures placed near the tokamak's wall and they have to propagate…

The optical afterglows of gamma-ray bursts can be used to probe the physics, geometry, and environments of gamma-ray bursts. In this article I discuss the how spectra and photometry can be used to constrain fireball parameters, describe…

Astrophysics · Physics 2015-06-24 S. T. Holland

We propose a new model for the extended Ly alpha blobs found recently at high redshift z ~ 3. The observational properties of these blobs are; 1) the observed Ly alpha luminosities are ~ 10^{43} h^{-2} ergs s^{-1}, 2) they appear elongated…

Astrophysics · Physics 2009-10-31 Yoshiaki Taniguchi , Yasuhiro Shioya

Blazars are a class of active galactic nuclei which host relativistic jets oriented close to the observer's line of sight. Blazars have very complex variability properties. Flares, namely flux variations around the mean value with a…

High Energy Astrophysical Phenomena · Physics 2022-01-19 Ze-Rui Wang , Ruo-Yu Liu , Maria Petropoulou , Foteini Oikonomou , Rui Xue , Xiang-Yu Wang

The blazar 3C 279 is well known for its rapid and large-amplitude variability. On 20 December 2013, the source exhibited an orphan {\gamma}-ray flare characterized by a flux-doubling timescale of a few hours, a very hard spectrum, a…

High Energy Astrophysical Phenomena · Physics 2026-05-04 Sébastien Le Bihan , Anton Dmytriiev , Andreas Zech