scholarly journals The Fine Temporal Structure of the EV Lacertae Flare on February 6, 1986 at the C IV (λ1550 Å) Resonance Line I. Observations

1989 ◽  
Vol 104 (2) ◽  
pp. 67-69
Author(s):  
B.A. Burnasheva ◽  
R.E. Gershberg ◽  
A.M. Zvereva ◽  
I.V. Ilyin ◽  
N.I. Shakhovskaya ◽  
...  
Keyword(s):  
Wavelength Range ◽  
Time Resolution ◽  
Resonance Line ◽  
Narrow Band ◽  
Temporal Structure ◽  
Flare Star ◽  
High Time Resolution ◽  
Wide Wavelength Range ◽  
Ev Lac ◽  
Fine Temporal Structure

AbstractWhile monitoring the flare star EV Lac with high time resolution using the Space Astrophysical Station ASTRON, a rather strong flare was recorded. During this event, flare emissions were detected in the C IV (λ1550 Å) UV line, in the narrow band continuum at λ2434 Å (28 Å bandwidth) and in the wide wavelength range from 1700 Å to 6500 Å, all emission enhancements taking place within 10 s. About 50 s after the flare start, a fast and very powerful burst of the C IV line took place.

scholarly journals Spectral and Photometrical Investigation of EV Lac in Different States with High Time Resolution

1995 ◽  
Vol 151 ◽  
pp. 85-86
Author(s):  
G.M. Beskin ◽  
S.N. Mitronova ◽  
I.P. Panferova
Keyword(s):  
Wavelength Range ◽  
Spectral Resolution ◽  
Time Resolution ◽  
Dead Time ◽  
Flare Star ◽  
Special Astrophysical Observatory ◽  
High Time Resolution ◽  
Photometric Monitoring ◽  
Ev Lac ◽  
Observation Method

Spectroscopic and photometric monitoring of the flare star EV Lac was carried out with the 6-m telescope of the Special Astrophysical Observatory on the following 3 nights: 1993 September 10 (18:54-20:16 UT), 11 (17:46-20:03 and 21:25-22:16 UT) and 12 (19:46-20:08 and 21:23-22:21 UT).We used the observation method described in detail by Berdyugin et al. (1994) and Alekseev et al. (1994). Observations were carried out with the 1024 channel TV scanner (Drabek et al. 1986) installed on the spectrograph SP-124 at the Nasmyth focus which covered a wavelength range 3480-5530Å with a spectral resolution 2Å per channel. Exposure times were 3 — 5 minutes, the signal/noise ratio was 20 at 3500Å and 40 at 5500Å and dead time between exposures was 10 — 15 sec. 92 spectra were obtained in total.

scholarly journals A New Technique for Precise Stellar Photometry: Application to Small-Scale Activity of EV Lacertae

1995 ◽  
Vol 151 ◽  
pp. 133-134 ◽  
Author(s):  
B.E. Zhilyaev
Keyword(s):  
Time Resolution ◽  
High Time ◽  
Small Scale ◽  
High Time Resolution ◽  
Stellar Photometry ◽  
A New Technique ◽  
Ev Lac ◽  
Counting Statistics ◽  
Simple Integration ◽  
Resolution Data

AbstractA new prefiltering technique (PFT) for precise stellar photometry is described. It has been proved that the prefiltered and added high-time resolution data provide an increase in S/N ratio by factors 1.3 — 1.7 in comparison with simple integration. The PFT allows to detect event amplitudes which are comparable to that caused by counting statistics. Adopting the PFT, our observations reveal small-scale flare events in the subsecond range in EV Lac.

scholarly journals A short-lived flare of EV Lacertae

1990 ◽  
Vol 137 ◽  
pp. 35-36
Author(s):  
B. E. Zhilyaev ◽  
Ya. O. Romanjuk ◽  
O. A. Svyatogorov
Keyword(s):  
Fine Structure ◽  
Light Curve ◽  
Time Resolution ◽  
Time Scale ◽  
High Time ◽  
High Time Resolution ◽  
Decay Times ◽  
Ev Lac

Flare events on a time scale of the order of one second were observed on EV Lac by Gershberg and Petrov [1], Zalinian and Tovmassian [2], Tsvetkov, Antov and Tsvetkova [3]. The nature of such phenomena is very mysterious. We hope that monitoring of EV Lac with high time resolution will yield the information about growing and decay times as well as fine structure of the light curve and color one. A short-lived flare of EV Lac was recorded in U and V bands in 1989, September 3 2h 14m 30s UT. The duration of the event was about 150 milliseconds.

scholarly journals Statistics of flares observed for UV Ceti type stars YZ CMi, AD Leo, and EV Lac at the Okayama Observatory

1990 ◽  
Vol 137 ◽  
pp. 43-47
Author(s):  
K. Ishida
Keyword(s):  
Time Resolution ◽  
High Time ◽  
High Time Resolution ◽  
Ceti Type ◽  
Flare Stars ◽  
Ev Lac

Photoelectric monitoring of flare stars YZ CMi, AD Leo, and EV Lac has been done at the Okayama Observatory since early 1970s. This is a simultaneous UBV observations with a high time resolution. Some statistics of the flares of the UV Ceti type stars are presented.

Configuration and Evolution of Solar Magnetic Fields

1970 ◽  
Vol 1 (8) ◽  
pp. 371-372 ◽  
Author(s):  
D. Schatz
Keyword(s):  
Active Region ◽  
Magnetic Fields ◽  
Wavelength Range ◽  
Time Resolution ◽  
Large Time ◽  
Field Configuration ◽  
High Time Resolution ◽  
Solar Magnetic Fields ◽  
Line Centre ◽  
The Continuum

Observations were made on 1970 February 9 using the Culgoora magnetograph to study the configuration and evolution of magnetic fields in a solar active region with high time resolution. The region observed was located at N20 E25 at the beginning of the observations which commenced at February 8, 22h 59m U.T. and finished at February 9, 07h 24 m. The magnetic fields were observed in the light of Cal 6102.7Å. Over a wavelength range corresponding to an intensity from 1/8 to 1/2 of the way up from line centre to the continuum on the blue side of the Une there is no apparent change in the field configuration, and the observations were made at a wavelength corresponding to the mid-point of this range. Exposures were made approximately every two minutes, with occasional large time gaps for instrumental adjustments.

scholarly journals Two-colour observations of spikes and flares by high time resolution

1990 ◽  
Vol 137 ◽  
pp. 33-34
Author(s):  
V.P. Zalinian ◽  
A.A. Karapetian ◽  
H.M. Tovmassian
Keyword(s):  
Time Resolution ◽  
High Time ◽  
High Time Resolution ◽  
Long Duration ◽  
Flare Stars ◽  
Ev Lac

Observations of flare stars with high time resolution permit to register spiky type flares and also to study in detail bright curves of flares. In Byurakan observatory observations of EV Lac have been made with 0.1 s time resolution simultaneouslyin two filters “U” and “B” [1-3]. These observations permited to detect flares of a burst type (Fig.1) and also to reveil multipeak structure of long duration flares. It is necessary to stress that simultaneous observations in two colours increas appresiably the thrustworthiness of the registered spiky flares.

scholarly journals The Fine Temporal Structure of The EV Lacertae Flare on February 6, 1986 at the C IV (λl550 Å) Resonance Line II. Interpretation

1989 ◽  
Vol 104 (2) ◽  
pp. 71-74
Author(s):  
M.M. Katsova ◽  
M.A. Livshits
Keyword(s):  
Temporal Structure ◽  
Elementary Event ◽  
Radiative Shock ◽  
Gas Condensation ◽  
Gas Dynamic ◽  
Explosive Evaporation ◽  
Optical Continuum ◽  
Ev Lac ◽  
Fine Temporal Structure ◽  
Theoretical Intensity

AbstractFlare optical continuum with duration above one minute is emitted by a gas condensation with T ≈ 104 K, which may form in a gas-dynamic process. The light carve slope implies that this flare consists of several elementary events. The features of the initial C IV line burst during one elementary event are determined by numerical simulation. The comparison of theoretical intensity and duration of the C IV burst with the observations of the EV Lac flare on February 6, 1986 shows that the observed elementary event in the C IV line is consistent with the formation of a radiative shock wave with an explosive evaporation of the chromosphere. The possibility of the appearance of C IV doublet emission, accompanying the entire process, is also discussed.

scholarly journals Short-Time Flare Events of EV Lac

1995 ◽  
Vol 151 ◽  
pp. 80-81 ◽  
Author(s):  
B.E. Zhilyaev ◽  
I.A. Verlyuk
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Time Resolution ◽  
Flare Star ◽  
Flare Activity ◽  
Flare Stars ◽  
Ev Lac ◽  
Short Time

Moffett (1972) pointed out the existence of short-time outbursts in flare stars as long ago as 1972. Gershberg & Petrov (1986) had registered a flare in EV Lac with a duration of 28.4 and an amplitude of 38.4 in 1984 with ASTRON. In recent years, a few reports appeared about observations of short-time outbursts in EV Lac with a duration in the range from 08.1 to several seconds. These results were summarized briefly by Zhilyaev (1993). Our observations confirm the existence of short-time flare activity on EV Lac.The observations reported here were obtained at the 60 cm telescope at the Peak Terskol high-altitude Observatory (3 100 m above sea level) with a highspeed two-channel photometer (Zhilyaev et al. 1992) in B as well as simultaneously in both, U and V bands, with a time resolution down to 08.1. A new prefiltering technique (Zhilyaev 1995) has been used for the detection of smallscale activity of the flare star EV Lac.

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