In order to measure the density of the Universe, it is necessary to sample a region that is larger than the scale on which the Universe becomes approximately homogeneous. ... When applied to clusters of galaxies we find a mass to luminosity ratio that implies a density of the Universe that is about 0.3 times the critical density. ... Thus the mass-to-muinosity ratio appears to vary with the size of the region measured, from 3 in the solar neighborhood to 30 in galaxies to 300 in clusters of galaxies. ...

... 2001: . The distances to 50 galaxies in the vicinity of three most nearby galaxy clusters were measured. The radius of the "zero velocity sphere", isolating each group from the cosmological expansion is in the range from 0.95 to 1.25 Mpc for these groups, leads to the estimates of the total mass of groups ranging from 1.2 to 2.7 trillion solar masses. These results agree with the value of the mean matter density in the Local Universe from 0.05 to 0.10 in critical density units. ...

Stellar population of the interacting galaxies M51. ... Stellar photometry of about one million stars in the system of the interacting galaxies M51 has been carried out on the basis of the ACS images of the Hubble Space telescope. ... A comparison of the stellar distribution in the main galaxy NGC 5194 with the empirical model of the distribution of stars showed their similarity, in spite of interaction in the system. ...

The project of the informational system creation on the problem of evolution of radio galaxies, as a part of the "Big Trio" project aimed on studing of distant radio galaxies, is designed. This system allows a user to operate with simulated curves of spectral energy distributions (SED) to estimate ages and redshifts by photometry data. Authors use SEDs of several models for different types of galaxies. ... The HTTP and e-mail access is organized to this system. ...

... Corresponding gates in each row are connected in parallel at both edges of the array. ... Other gates. ... otherwise indicated, 45 kpixels/sec and standard voltages using a dual slope CDS circuit (8 µs integration time) Minimum Format Pixel Size Imaging Area Dark current (MPP), 20° C equivalent Readout noise Front Back Full Well signal Output gain CTE per pixel Typical 512 x 512 pixels 24 µm x 24 µm 12.3 mm x 12.3 mm 50 pa/cm2 5 electrons 7 electrons 350,000 electrons 1.5 µV/ electron 0 ...