The quantity of dust in a spiral disk can be estimated using the dust's typical emission or the extinction of a known source. In this paper we compare two techniques, one based on emission and one on absorption, applied to sections of 14 disk galaxies. ... Hence, they depend differently on the average number and optical depth of ISM structures in the disk. The small-scale geometry of the cold ISM is critical for accurate models of the overall energy budget of spiral disks. ...

I'm interested in the structure of interstellar ``clouds'' (filaments, sheets, or whatever) of gas and dust over a wide range of scales, from Galactic spiral arms to AU-scale features -- also how these structures form and interact. ... The possibility of clumpy dust scattering in the Pleiades reflection nebula, which might explain its otherwise surprising UV scattering properties . ... Intricate structure of H I emission and self-absorption in the CGPS . ... Fractal studies of molecular clouds . ...

... Laboratory for Spectroscopy of Molecular Structures . ... Optics and spectroscopy of molecular and liquid crystals, fullerenes, superthin molecular films. Optical studies of structure, phase transitions, pretransitional phenomena, structural modifications in external field and under high pressure. ... Methods developed in the laboratory enable to determine in free standing films of different types liquid crystals values of polarization, two-dimensional constants of orientational elasticity. ...

... 2004 January 1 . Structure in N63A . Credit: X-ray: J. Warren ( Rutgers ) et al., CXC , NASA . Optical: Y.Chu ( U. Illinois ), STScI , NASA . Radio: J.Dickel (U. Illinois) et al., ... Radio (red) and optical emission (green) are brighter near the central regions where the x-rays seem to be absorbed by denser, cooler material on the side of the expanding debris cloud facing the Earth. ... About APOD | ... NASA Web Site Statements, Warnings, and Disclaimers . ...

The efficiency of interaction of radiation with a particle and hence its optical properties depend on the particle chemical composition, size, shape, structure, etc. ... Particle size expressed in units of the wavelength of incident radiation, together with chemical composition, most strongly affects the optical properties of a scatterer. ... There are many methods to solve the light-scattering problem for a homogeneous spheroid (our survey of the light-scattering methods see here ). ...

This home page belongs to small group of scientists working at . Sternberg Astronomical Institute which is a part of Moscow State University . ... Электронная библиотека научно-технической и художественной литературы (доступна только из ГАИШ) . ... Local staff . Dr. Edward Kononovich (konon -at- sai.msu.ru), Associate Professor . ... Dr. Sergey Ayukov (asv -at- sai.msu.ru), Research Fellow, Webmaster of the group . ... Joint seminar of Solar Studies Structure Group and Solar Photometry Group . ...

... Just as magnetic storms are composed of substorms, the substorms themselves seem to be composed of smaller scale events. ... steplike expansion of the auroral bulge (Vorobjev and Rezenov, 1973; Sergeev and Yahnin, 1979; Murphree and Cogger, 1992; Nakamura et al., 1993) . ... 1990) . ... fine structure in the bursts of bremsstrahlung X-rays (Lazutin et al., ... Nakamura, R., T. Oguti, T. Yamamoto, and S. Kokubun, Equatorward and poleward expansion of the auroras during auroral substorms, J. Geophys. ...

... The HH flow associated with young stellar object HL Tau has an exciting history and even until now the origin of some its features is not clear yet. ... Knotty structures of Herbig-Haro jets are common phenomena and knowing the origin of such structures is essential for understanding the processes of jet formation. ... In the flow detected compact knots with high (-150 km/s) and bow shape structures in front of those, with low radial velocities (-50 km/s). ...

Databases (NSDC) of the Natural Planetary Satellites. ... NSDC: Database of astrometric observations of Natural Planetary Satellites . ... They are thoroughly looking for observations in different sources, creating their owndatabases which are then mostly inaccessible to other researchers. ... In the file "content" with explications, the reference is given to the data source as well as the bibliographic reference. ... Data sources. ... Why a specific bibliographic database for Natural satellites? ...

... overview of pyQC . ... output used by . ... All pyQC scripts and modules share a similar structure. Python offers to group functions, classes, etc. into modules which can be imported by different scripts. ... In order to avoid confusion if names are used by different (especially external) modules, the QC scripts use the 'from' statement only for pyQC modules, i.e.: . ... For other modules, the simple 'import' statement is used: . ... Python modules are also used for keeping script configuration. ...

In Figure 10 (528 Kbytes) we show an image of the LMC taken in Red light. In this passband one measures the intensity and appearance of the galaxy in the light of stars which are about 5 billion years old. ... Lastly, we include in Figure 12 , another image taken with Parking Lot CCD. ... In sum, this article has summarized the various systems that are capable of performing wide field CCD imaging. ... Figure 1: Mark Cornell and David Chappell - McDonald Observatory, University of Texas . ...

RATAN-600 OBSERVATIONS OF MICROWAVE STRUCTURE OF THE QUIET SUN T.I. Kaltman, V.M. Bogo d, A.N. Korzhavin, S.Kh. ... A small-scaled structure with the size of 20-40 arc sec is regularly observed with RATAN-600 one-dimensional observations. ... The daily monitoring with RATAN-600 observations provides p ossibilities to regularly estimate a state of the quiet Sun by emission characteristics of microwave small-scaled structure and to trace rises of new centers of activities. ...

... Carefully measure the diameter of the craters formed by the impact without disturbing the sand. ... Crater diameter increases with increasing mass. ... Without disturbing the sand, carefully measure the crater diameter. ... Did you measure any difference in the diameters of the craters? Yes, as velocity increases, so does crater diameter. ... Impact cratering. ... Impact craters can be demonstrated with younger or less advanced students using mud instead of sand and ball bearings. ...

M. ( / DIAS, Ireland), A. (ISDC, Switzerland) 1 - Key Question Only 3 binary systems regularly observed in TeV: PSR B1259-63 (young pulsar +Be star, P=3.4 y) LSI +61 303 (comp. source + Be star, P=26.42 d) LS 5039 (comp. source + O star, P=3.9 d) Origin of the high-energy emission? ... 2006; Neronov &Chernyakova 2007 4 3.4 years orbital period. e~0.87 Correlated variability with a sharp rise ( "two bumps structure" ) is seen in radio, X-ray (and TeV?) bands. ...

... Takuya Akahori "Faraday Rotation Measure due to the Intergalactic Magnetic Field" . Shae Brown "Cross-correlation of ATLAS and Spitzer-SWIRE Surveys: Probing intergalactic magnetic fields" . Roger Clay "Using low energy cosmic rays to investigate local galactic magnetic fields" . Roland Crocker "A new lower limit on the magnetic field around the Galactic Centre" . ... JinLin Han "Rotation measures of pulsars and radio sources for Galactic magnetic fields" . ...

... The main research task of the LRS was an investigation of interstellar medium of our Galaxy using its line emission in radio domain with the help of the gratest RATAN-600 Radio Telescope. ... The complex investigation of the Interstellar Clouds structure on the different scales and with the different radio lines for understanding of structure, dynamics and evolution of interstar gas and its interaction with other galactic constituents and the conditions for star formation. ...

... We describe a parallel code for 3-D structure detection and morphological analysis. The method is based on a multiscale technique, the wavelet transform and on segmentation analysis. ... This paper presents a new parallel code, that allows a rapid structure detection and morphological analysis in a 3-D set of data points. ... Segmentation analysis. ... Our code is based on the programming paradigm MASTER/SLAVE . ... Finally, the morphological analysis is executed by the master. ...

... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. February 7, 1998 . COBE Hotspots: The Oldest Structures Known . ... After computer processing to remove contributions from nearby objects and the effects of the earth's motion , the map shows temperature variations in the early Universe as red "spots". These spots are the oldest, most distant structures known. ... About APOD > . ...

We discuss the influence of the non-thermal velocity (micro-turbulence) on the formation of chromospheric lines in the atmospheres of late type dwarfs. A review of previous work shows a variety of different atmospheric structures and consequently different computed line profiles. ... Using the analogy with the solar case and the latest results of the non-thermal component widths as derived from instruments on-board SOHO we model H\alpha and the NaI lines in an active dMe star GL616.2. ...

... It is reasonable to expect that UV part of the irradiating spectrum is most influenced by the grain evolution (growth and sedimentation ) which marks the very initial stage of planet formation. 2 log J [erg sґ1 cmґ2] 1 0 -1 -2 -3 1000 BB 40 0 0 (A5 ) BB 20 0 00 (A5) Drai ne (A5 ) BP Ta u (A5) BB 40 0 0 (GS) BB 20 0 00 (GS) Drai ne (GS) BP Ta u (GS) Disk Model Density distribution is based on a 1+1D disk ... Green lines are used for a model with dust growth and sedimentation. ...