418 research outputs found
Super-Eddington accretion in the Q2237+0305 quasar?
The interband time lags between the flux variations of the Q2237+0305 quasar
have been determined from light curves in the Johnson-Cousins V, R, and I
spectral bands. The values of the time lags for filter pairs R-V, I-R, and I-V
are significantly higher than those predicted by the standard accretion disk
model by Shakura and Sunyaev. To explain the discrepancy, the idea of a
supercritical accretion regime in quasars considered in 1973 by Shakura and
Sunyaev is applied. This regime has been shown by them to cause an extended
scattering envelope around the accretion disk. The envelope efficiently
scatters and re-emits the radiation from the accretion disk and thus increases
the apparent disk size. We made use of analytical expressions for the envelope
radius and temperature derived by Shakura and Sunyaev in their analysis of
super-Eddington accretion and show that our results are consistent with the
existence of such an envelope. The corresponding parameters of the accretion
regime were calculated. They provide the radii of the envelope in the V, R, and
I spectral bands consistent with the inter-band time lags determined in our
work.Comment: 11 pages, 4 figure
Obtaining cyclopentanone from acidic wastewater of caprolactam production
It has been shown that adipic acid released from the by-products of caprolactam production is a promising raw material for the production of cyclopentanone. The thermal stability of calcium adipate was investigated by the derivatographic method and the conditions were selected that ensure the yield of at least 50% of the target cyclopentanone with a purity of at least 99%
Color Effects Associated with the 1999 Microlensing Brightness Peaks in Gravitationally Lensed Quasar Q2237+0305
Photometry of the Q2237+0305gravitational lens in VRI spectral bands with the
1.5-m telescope of the high-altitude Maidanak observatory in 1995-2000 is
presented. Monitoring of Q2237+0305 in July-October 2000, made at nearly daily
basis, did not reveal rapid (night-to-night and intranight) variations of
brightness of the components during this time period. Rather slow changes of
magnitudes of the components were observed, such as 0.08 mag fading of B and C
components and 0.05 mag brightening of D in R band during July 23 - October 7,
2000. By good luck three nights in 1999 were almost at the time of the strong
brightness peak of image C, and approximately in the middle of the ascending
slope of the image A brightness peak. The C component was the most blue one in
the system in 1998 and 1999, having changed its (V-I) color from 0.56 mag to
0.12 mag since August 1997, while its brightness increased almost 1.2 mag
during this time period. The A component behaved similarly between August 1998
and August 2000, having become 0.47 mag brighter in R, and at the same time,
0.15 mag bluer. A correlation between the color variations and variations of
magnitudes of the components is demonstrated to be significant and reaches
0.75, with a regression line slope of 0.33. A color (V-I) vrs color (V-R) plot
shows the components settled in a cluster, stretched along a line with a slope
of 1.31. Both slopes are noticeably smaller than those expected if a standard
galactic interstellar reddening law were responsible for the differences
between the colors of images and their variations over time. We attribute the
brightness and color changes to microlensing of the quasar's structure, which
we conclude is more compact at shorter wavelengths, as predicted by most quasar
models featuring an energizing central source.Comment: 14 pages, 7 figures, LaTeX, submitted to A&
Konus-Wind and Helicon-Coronas-F Observations of Solar Flares
Results of solar flare observations obtained in the Konus-Wind experiment
from November, 1994 to December, 2013 and in the Helicon Coronas-F experiment
during its operation from 2001 to 2005, are presented. For the periods
indicated Konus-Wind detected in the trigger mode 834 solar flares, and
Helicon-Coronas-F detected more than 300 solar flares.
A description of the instruments and data processing techniques are given. As
an example, the analysis of the spectral evolution of the flares
SOL2012-11-08T02:19 (M 1.7) and SOL2002-03-10T01:34 (C5.1) is made with the
Konus-Wind data and the flare SOL2003-10-26T06:11 (X1.2) is analyzed in the
2.223 MeV deuterium line with the Helicon-Coronas-F data.Comment: Published version. A list of the Konus-Wind solar flare triggers and
figures of their time profiles are available at
http://www.ioffe.ru/LEA/Solar
Tropospheric forcing of the boreal polar vortex splitting in January 2003
e dynamical evolution of the relatively warm stratospheric winter season 2002–2003 in the Northern Hemisphere was studied and compared with the cold winter 2004–2005 based on NCEP-Reanalyses. Record low temperatures were observed in the lower and middle stratosphere over the Arctic region only at the beginning of the 2002–2003 winter. Six sudden stratospheric warming events, including the major warming event with a splitting of the polar vortex in mid-January 2003, have been identified. This led to a very high vacillation of the zonal mean circulation and a weakening of the stratospheric polar vortex over the whole winter season. An estimate of the mean chemical ozone destruction inside the polar vortex showed a total ozone loss of about 45 DU in winter 2002–2003; that is about 2.5 times smaller than in winter 2004–2005.
Embedded in a winter with high wave activity, we found two subtropical Rossby wave trains in the troposphere before the major sudden stratospheric warming event in January 2003. These Rossby waves propagated north-eastwards and maintained two upper tropospheric anticyclones. At the same time, the amplification of an upward propagating planetary wave 2 in the upper troposphere and lower stratosphere was observed, which could be caused primarily by those two wave trains. Furthermore, two extratropical Rossby wave trains over the North Pacific Ocean and North America were identified a couple of days later, which contribute mainly to the vertical planetary wave activity flux just before and during the major warming event. It is shown that these different tropospheric forcing processes caused the major warming event and contributed to the splitting of the polar vortex
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