Next: Examples and Photometric Up: Image Restorations of High Previous: Introduction . ... where is the intensity of the point sources (mainly zero apart from -functions at the positions of designated sources) and is the intensity of the background. ... When is zero the objective function becomes the same as that of the standard Lucy-Richardson technique. takes the form of an entropy expression which may be calculated in two ways, relative to a flat background: . ...

... The HST uses an onboard model of its orbit to perform in real-time various control functions relating to spacecraft operations and observation support. ... New coefficients for the ephemeris are updated every other day, and are archived as FITS keywords for each HST observation data set. Using these coefficients,an observer can perform a variety of calibration and characterization calculations relating to the orbital position and velocity of the telescope. ...

SMITHSONI AN OPHYSICA TR L O AS VATORY ER BS C AD IA A EM IA SINIC SMA SMA Imaging of the HRL Masers in MWC349A Jonathan Weintroub1, James Moran1, Ramprasad Rao2, Hiroko Shinnaga3, David Wilner1 Ken Young1 1 2 3 Harvard-Smithsonian ... 96720 Abstract: In September 2004 and September 2005 we used the SMA in an extended configuration to map the hydrogen recombination line (HRL) maser spots that originate in the envelope of the peculiar star MWC349A. H30 Alpha (231.9 ...

Next: Transparency of the Stochastic Up: Model of the Galaxy Previous: Frequency distribution of galactic . ... The parameters of the model resulted from a numerical fitting of various data, such as the observed distribution of the young star population and neutral hydrogen, the density of population II stars in the vicinity of the Sun, the galactic rotation curve and the dynamics and distribution of globular clusters   and dwarf irregular satellites of the Galaxy. ...

... The observed distributions of stars of different ages and metallisities in the Z coordinate relative to Sun: (a) young ( t 3 Gyr) metall-rich ( [Fe/H] -0.13 ) stars; (b) young metal-poor ( [Fe/H]<-0.13 ) stars; (c) old ( 3 Gyr) metal-rich stars, and (d) old metal-poor stars. ... next figure | previous figure . ...

XMM­Newton CCF Release Note XMM­CCF­REL­86 EPIC MOS ASTROMETRY B. Altieri August 2, 2001 1 CCF components Name of CCF VALDATE List of Blocks changed CAL VERSION XSCS flag EMOS1 LINCOORD 0016 2000­01­01T00:00:00 FOV NO EMOS2 LINCOORD 0016 2000­01­01T00:00:00 FOV NO 2 Changes The relatove positions between CCDs for both MOS cameras have been adjusted to provide the highest astrometric accuracy over the full field­of­view of the MOS cameras. ...

... Our resulting sample of ELGs presented in Tables 2 and 3 is not artificially biased to any specific type of galaxies. ... Since we are looking for selection of a sample of Case BCGs, it is interesting to examine how the detected BCGs are connected with Case emission-line codes. ... Altogether BCGs comprise about 60 % of all Case ELGs which display emission lines in our spectra, or about 44 % of all Case galaxies with some emission-line code. ... Among those with the code ``w'' about 40 % are BCGs. ...

... To plot the data (and model, here xitau.model), I have read the model, computed the model values for the ASTROMETRY, and used Plot|ASTROMETRY to produce the ASTROMETRY plot widget. ... First, plot the data and with Util|Ellipse and the mouse buttons interactively define an apparent ellipse to fit your data as best as you can. ... Under Util|Orbit, there is a Thiele-Innes procedure to estimate the orbital elements using your apparent ellipse and Kepler's laws! ... Back to tour page . ...

... Subject and Problems of Stellar Astronomy. ... Plane of Galaxy, Methods of Its Location Determination. ... Stars Distances. ... Other Methods of Stars Distances Determination. ... Tangential Velocities, Their Determination by Self-Motions. ... Determination of Solar Apex and Spatial Velocity by Radial and Spatial Velocities of Stars. ... Features of Orientation and Parameters of Peculiar Stellar Velocities Ellipsoid. ... General and Selective Light Absorption in Galaxy. ... Darc Clouds in Galaxy. ...

Full Stokes 327-MHz Continuum Observations of the GALFACTS Pilot Region Wasim Ra ja, Avinash Deshpande, Tapasi Ghosh, Chris Salter & Andrew R. Taylor Background and Scientific Justification Several existing surveys have mapped the polarized intensity of the extended Galactic emission at various frequencies using single dish as well as synthesis imaging. ... The underlying distribution of the polarized emission and the magneto-ionic medium would be apparent in the images resolved across Faraday depth. ...

... W. Steffen , T.P. Krichbaum , S. Britzen and A. Witzel . ... Such oscillations can result from precession of the jet, helical magnetic fields, or helical instabilities. ... VLBI monitoring of the milliarcsecond scale structure shows stationary components at about 5, 1.4 and 0.4 mas separation from the core ( Eckart et al. ... The accumulated VLBI data show that the observed components and the continuous jet structure are aligned along a curved, oscillating ridge line (see Figure 1 ). ...

... A universal physical relation for quasars . ... Harvey Tananbaum and his collaborators have first observed a relation between the soft X-ray and the optical/ultraviolet emission in AGN in 1979. Such relation is nonlinear, and it is usually parameterized as dependence between the logarithm of the monochromatic luminosities at 2500 †Е ( L 2500†Е ) and 2 keV ( L 2keV ) . ... Yet, the dispersion along the L 2500†Е тАУ L 2keV relationship is found to be rather high, typically ~0.35тАУ0.4 in log units. ...

spaceweb@oulu.fi - last update: 20 September 1998, 2020 UT (RR) . Traveling Convection Vortex (TCV) is a name given to a specific type of daytime magnetic impulsive events observed by high-latitude ground-based magnetometer arrays. Since the most likely source for TCVs is the solar wind , they are considered to be important processes in transfering energy from the solar wind into the magnetosphere . ... For example, one AMPTE Lithium release in the solar wind caused a TCV event . ...

Catalogue of double stars . The Pulkovo Visual Double Star Catalogue Based on the Relative Positions Derived from the Photographic Observations Made with 26-inch Refractor since 1960. ... Into the present catalogue the seasonal mean relative positions ( r and q 2000 ) are included for 234 visual double stars observed at Pulkovo with 26-inch refractor from 1960 through 2001. ... The photographic and CCD observations of visual double stars are being continued now. ... The Format of the Catalogue. ...

... 2.3 Establishing the Extragalactic Distance Scale . ... 2.3.2 The Second Rung: Distances to stellar clusters . ... 2.3.4 Distances to Local Group Galaxies . ... The Luminosity Function of Planetary Nebulae . ... 3.2.2 Clusters of Galaxies . ... 4.2 Evidence for Dark Matter as a Function of Scale Size . ... 4.3 Other Dark Matter Indicators for Galaxies . ... What is the nature of the large-scale distribution of matter in the universe as traced by the three-dimensional galaxy distribution? ...

... Archives . ... ArXiv] SVM and galaxy morphological classification, Sept. 10, 2007 . ... On the Metallicity-Color Relations and Bimodal Color Distributions in Extragalactic Globular Cluster Systems by M. Cantiello and J. P. Blakeslee . Many observations on globular cluster systems (GCS) show bimodal distributions in color and metallicity space. ... Based on their simulation study, (V-H) and (V-K) are confirmed to be good colors for revealing unbiased bimodal metallicity distributions in GCS. ...

... astro-ph . ... Whitespace-separated words are treated as AND ed. Show 10 50 100 articles per page in Full Compact mode . ... Quasar Variability in the Framework of Poissonian Models . ... It is shown that in this very general framework the well established anti-correlation between variability amplitude and wavelength can only be understood as an effect of an underlying spectral component which remains stable on long time-scales, and is redder than the variable component. ...

... A reconstruction method of 3D vector velocity field (three components of velocities) of gas in disks of spiral galaxies from observed line-of-sight velocity field is proposed. This method is based on Fourier analysis of observed velocity field. ... The knowledge of velocity field in spiral galaxies allows to clarify the nature of the galactic structures and mechanisms of their formation. ...

... Keck spectropolarimetry, giving spectral coverage from Ly- to beyond CIII], and HST imaging of a sample of powerful radio galaxies with has been obtained. ... This is a short progress report on a rather extensive programme we are carrying out to study the structure and composition of high redshift radio galaxies (HzRG) -- and, by implication, the host galaxies of radio quasars -- using observations in the optical, IR and mm bands. ... An example of the NICMOS and WFPC 2 imaging is shown in Figure 2 ...

... With enough velocity, a spacecraft can break loose from the Earth's gravity and enter an orbit around the Sun, like that of a planet. If it then orbits the Sun with the same period as the Earth--one year--it may keep a fixed position relative to Earth. ... If the distance is just right--about 4 times the distance to the Moon or 1/100 the distance to the Sun--the spacecraft, too, will need just one year to go around the Sun, and will keep its position between the Sun and the Earth. ...