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11.
G. S. Bisnovatyi-Kogan S. I. Blinnikov S. A. Silich 《Astrophysics and Space Science》1989,154(2):229-246
We present the results of calculations of blast waves propagation in plane-stratified medium, taking into account gravitational forces, pre-explosion gas motion and different laws of energy input into the cavity. The numerical hydrodynamic scheme based on infinitely thin-layer approximation is described. The results are compared with two-dimensional axisymmetric numerical calculations. The evolution of a superbubble in plane-stratified galactic disk is discussed. It is shown that late SNR structure is highly dependent on pre-supernova-interstellar gas relative motion. 相似文献
12.
Results of the analysis of the Comet Halley spectrophotometry,which has been carried out by H.K. Nazarchuk in 1985 with the
TVscanner of the 6-meter telescope (SAO, Russia) are presented. Timevariations in the intensities of the CN, CH, C2 and NH2bands were investigated using the series of spectra obtained inthe spectral region λλ=410÷ 510 nm. Theauto-correlation functions
for all the bands, thecross-correlation functions for C2 lines and their Fouriertransformations are calculated to determine the frequencies andperiods of the variations. A possibility
is considered thathigh-amplitude fast variations of spectral lines in Comet Halleyare caused by solar flares. The daily numbers
of solar spots andproton fluxes with energies of more then 1 MeV are compared withthe spectral variations of these lines.
It is shown that in theobservation periods the comet was projected onto an active regionof the Sun, but, among all the kinds
of solar activity, mainlythe solar proton flux with energies less than 4 MeV coincides intime with fast intensity variations
in the spectral lines. Analgorithm of cross-correlation analysis of discrete samplingseries with gaps is built, and average
cross-correlation coefficientsare calculated. 相似文献
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Sergey A. Silich & Guillermo Tenorio-Tagle 《Monthly notices of the Royal Astronomical Society》1998,299(1):249-266
Two-dimensional calculations of the evolution of remnants generated by the strong mechanical energy deposited by stellar clusters in dwarf galaxies ( M ∼ 109 –1010 M⊙) are presented. The evolution is followed for times longer than both the blowout time and the presumed span of energy injection generated by a coeval massive stellar cluster. The remnants are shown to end up wrapping around the central region of the host galaxy, while growing to kiloparsec-scale dimensions. Properties of the remnants such as luminosity, size, swept-up mass and expansion speed are given as functions of time for all calculated cases. The final fate of the swept-up galactic gas and of the matter processed by the central starburst is shown to be highly dependent on the properties of the low-density galactic halo. Superbubbles powered by star clusters, with properties similar to those inferred from the observations, slow down in the presence of an extended halo to expansion speeds smaller than the host galaxy escape velocity. Values of the critical luminosity required for the superbubbles to reach the edge of the galaxies with a speed comparable to the escape speed are derived analytically and numerically. The critical luminosities are larger than those in the detected sources, and thus the superbubbles in amorphous dwarf galaxies must have already undergone blowout and are presently evolving into an extended low-density halo. This will inhibit the loss of the swept-up and processed matter from the galaxy. 相似文献
15.
The Donbas Foldbelt is part of the Prypiat–Dnieper–Donets intracratonic rift basin (Belarus–Ukraine–southern Russia) that developed in Late Devonian times and was reactivated in Early Carboniferous. To the southeast, the Donbas Foldbelt joins the contiguous, deformed Karpinsky Swell. Basin “inversions” led first to the uplift of the Palaeozoic series (mainly Carboniferous but also syn-rift Devonian strata in the southwesternmost part of the Donbas Foldbelt, which are deeply buried in the other parts of the rift system), and later to the formation of the fold-and-thrust belt. The general structural trend of the Donbas Foldbelt, formed mainly during rifting, is WNW–ESE. This is the strike of the main rift-related fault zones and also of the close to tight “Main Anticline” of the Donbas Foldbelt that developed along the previous rift axis. The Main Anticline is structurally unique in the Donbas Foldbelt and its formation was initiated in Permian times, during a period of (trans) tensional reactivation, during which active salt movements occurred. A relief inversion of the basin also took place at this time with a pronounced uplift of the southern margin of the basin and the adjacent Ukrainian Shield. Subsequently, Cimmerian and Alpine phases of tectonic inversion of the Donbas Foldbelt led to the development of flat and shallow thrusts commonly associated with folds into the basin. A fan-shaped deformation pattern is recognised in the field, with south-to southeast-vergent compressive structures, south of the Main Anticline, and north- to northwest-vergent ones, north of it. These compressive structures are clearly superimposed onto the WNW–ESE structural grain of the initial rift basin. Shortening structures that characterise the tectonic inversion of the basin are (regionally) orientated NW–SE and N–S. Because of the obliquity of the compressive trends relative to the WNW–ESE strike of inherited structures (major preexisting normal faults and the Main Anticline), in addition to reverse displacements, right lateral movements occurred along the main boundary fault zones and along the faulted hinge of the Main Anticline. The existence of preexisting structures is also thought to be responsible for local deviations in contractional trends (that are E–W in the southwesternmost part of the basin). 相似文献
16.
We propose an approach for building facade interpretation ranging from uncalibrated wide-baseline image sequences to the extraction of windows. The approach comprises several novel features, such as determination of the facade planes by robust least squares matching, learning of implicit shape models for objects, particularly windows, and the determination of the latter by means of Markov Chain Monte Carlo (MCMC) employing an abstraction hierarchy generated via mathematical morphology. Results for the fully automatic approach show its potential and shortcomings. 相似文献
17.
Guillermo Tenorio-Tagle Sergey A. Silich Daniel Kunth Elena Terlevich Roberto Terlevich † 《Monthly notices of the Royal Astronomical Society》1999,309(2):332-342
The detection of Ly α emission in star-forming galaxies in different shapes and intensities (always smaller than predicted for case B recombination) has puzzled the astronomical community for more than a decade. Here we use two-dimensional calculations to follow the evolution of superbubbles and of the H ii regions generated by the output of UV photons from massive stars. We show the impact caused by massive star formation in the ISM of different galaxies and we look at the conditions required to detect Ly α emission from a nuclear H ii region, and the variety of profiles that may be expected as a function of time. 相似文献
18.
Daniel Kunth Françcois Legrand Guillermo Tenorio-Tagle Sergey Silich J. Miguel Mas-Hesse Miguel Cerviño 《Astrophysics and Space Science》2002,281(1-2):261-266
We show evidences that gas outflows occur in starburst galaxies as superbubbles evolve. We then question whether hot gas will
be expelled and enrich the IGM with metals or be retained within the host galaxy. For this purpose we construct three extreme
scenarios of the star formation histories for a sample of dwarf galaxies using either their present metallicity or their luminosity.
The three scenarios imply different mechanical energy input rates, those are compared with theoretical lower limits for the
ejection of processed matter out of host galaxies. The comparison strongly points at the existence of extended gaseous haloes
acting as a barrier that allows these galaxies to retain their metals and enhance their abundance. Our findings strongly point
that continuous star-forming processes, rather than coeval bursts, must contribute to the overall metallicity in our galaxy
sample.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
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S. A. Silich 《Astrophysics and Space Science》1992,195(2):317-330
The evolution of remnants produced by the correlated supernovae explosions in OB-associations is investigated. The 2.5-dimensional numerical hydrodynamic scheme based on thin layer approximation is proposed. Inhomogeneity of the gas density distribution, galactic disk shear, gravity, and continuous energy input from SNe explosions are taken into account. 相似文献