Results 291 to 300 of about 34,380 (305)

Optical behaviour of markarian 421 during high-energy flares

Astronomical & Astrophysical Transactions, 1997
Abstract In this paper we present the optical behaviour of Mrk 421 from 1992 to April, 1995. The observations were obtained at the Perugia University Observatory with the automatic imaging telescope in the BVR c I c broad-bands. Visual estimates done by “The Astronomer” group and the British Astronomical Association (BAA) are inclosed in the light ...
M. Fiorucci, TOSTI, Gino, G. M. Hurst
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Flare-Associated Optical Phenomena

1976
Besides the optical flare proper a large number of various optical phenomena are observed in the solar chromosphere and corona that obviously are related in some way or the other to the flare event. We may divide them into four different types: (a) Activation of filaments (or prominences when seen on the limb) preceding the optical flare.
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Coronal Loops and Optical Radiation from Flaring Stars

Geomagnetism and Aeronomy, 2020
The possibility that large-scale coronal loops of solar-type stars and M dwarfs make a significant contribution to the white-light continuum emission is considered. It is shown that that the existence of high-density (>1012 cm–3) coronal loops contradicts the standard model of solar and stellar flares.
Yu. T. Tsap, A. V. Stepanov, Yu. G. Kopylova, Z. S. Akhtemov, V. M. Malashchuk   +4 more
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Optical Emission from Stellar Flares

1996
Optical observations of stellar flares on late-type stars are common, particularly in the U and B bands of the Johnson system. The reason for this preference is the large proportionate increase in the flux in the ultraviolet during flares on late-type stars, as compared to the quiescent stellar continuum which peaks in the near infra-red.
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IUE/OPTICAL/VLA flares on AD Leo

2008
We discuss joint observations of flares on the dMe star AD Leo made with IUE, the VLA, and the Tinsley photometer at the University of Hawaii's 24-inch reflector on Mauna Kea. We find that optical emission is correlated with C IV while radio emission is better correlated with He II.
Dale E. Gary, P. B. Byrne, C. J. Butler
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An example of radio and optical homologous flares

Solar Physics, 1970
Fokker (1967) has raised the question of whether the optical and radio homologies of flares are correlated. Two 2b flares occurring nearly 54 h apart (July 9 and 12, 1968) were observed at 29 wavelengths from Hα+4.00 A to Hα−4.26 A and at 10-cm radio. Adjacent pictures were spaced 0.295 A and 2 sec apart.
K. P. White, T. J. Janssens
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Measuring and modeling flare in optical lithography

SPIE Proceedings, 2003
Flare, unwanted scattered light arriving at the wafer, is caused by anything that forces the light to travel in a “non-ray trace” direction. The amount of flare experienced by any given feature is a function of both the local environment around that feature (short range flare) and the total amount of energy going through the lens (long range flare ...
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Review of optical observations of solar flares

Solar Physics, 1987
The recent observations of solar flares, made with a Lyot filter and a spectrograph in Hα, HeD3, higher Balmer lines, metallic lines, and continuum, are discussed. It is important to study the energy supply of non thermal particle/ conduction/ irradiation into the lower atmosphere from the optical observations with high temporal and spatial resolutions.
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Solar gamma-ray flares that occur before low-power optical flares

Solar gamma-ray flares occurring within a few minutes before an optical flare on the Sun were studied. It was found that the intensity of gamma-ray flares per optical flare varies over the 11-year solar cycle and reaches a minimum near the maximum activity in the cycle.
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On the ionisation of hydrogen in optical flares

Solar Physics, 1973
Non-steady state and non-LTE effects on the ionisation equilibrium of hydrogen in optical flares are considered in terms of a two-level hydrogen atom. It is shown that, just as in the quiet low chromosphere, the ionisation equation is controlled by spontaneous recombination to the second level and by photoionisation from this level by photospheric ...
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