128 research outputs found

    CMB component separation in the pixel domain

    Full text link
    We show that the popular ILC approach is unstable in respect to the division of the sample of map pixels to the set of ``homogeneous'' subsamples. For suitable choice of such subsamples we can obtain the restored CMB signal with amplitudes ranged from zero to the amplitudes of the observed signal. We propose approach which allows us to obtain reasonable estimates of CC_\ell at 30\ell\leq 30 and similar to WMAP CC_\ell for larger \ell. With this approach we reduce some anomalies of the WMAP results. In particular, our estimate of the quadrupole is well consistent to theoretical one, the effect of the ``axis of evil'' is suppressed and the symmetry of the north and south galactic hemispheres increases. This results can change estimates of quadrupole polarization and the redshift of reionization of the Universe. We propose also new simple approach which can improve WMAP estimates of high \ell power spectrum.Comment: 7 pages, 5 figure

    Catalog of Radio Galaxies with z>0.3. III: Angular Sizes and Flux Density According to the NVSS Data

    Full text link
    We describe the procedure of the construction of a sample of distant (z>0.3z>0.3) radio galaxies using the NED, CATS and SDSS databases for further use in various statistical tests. We believe the sample to be free of objects with quasar properties. This paper is the third part of the description of the radio galaxies catalog that we plan to use for cosmological tests. We report the results of the sample of angular sizes for the NVSS survey list objects, and its preliminary statistical analysis. Three-parameter diagrams "angular size-redshift-flux density" and "angular size-redshift-spectral index", and their two-parameter projections are constructed. Three subsamples of radio galaxies are separated in the "source size--flux density" diagram.Comment: 6 pages, 4 figures, 1 tabl

    On the Spectral Index of Distant Radio Galaxies

    Full text link
    The problems of using the spectral index of radio galaxies in various tests, in particular, in selecting distant radio sources are considered. The history of the question of choosing a criterion of searching for distant radio galaxies based on the spectral index is presented. For a new catalog of 2442 radio galaxies constructed from NED, SDSS, and CATS data, an analytical form of the sp ectral index.redshift relation has been determined for the first time. The spectral index.angular size and spectral index.flux density diagrams have also been constructed. Peculiarities of the distribution of sources on these diagrams are discussed.Comment: 7 pages,5 figure

    The estimation of black-hole masses in distant radio galaxies

    Full text link
    We have estimated the masses of the central supermassive black holes of 2442 radio galaxies froma catalog compiled using data from the NED, SDSS, and CATS databases. Mass estimates based on optical photometry and radio data are compared. Relationships between the mass of the central black hole MpbhM_p^{bh} and the redshift zpz_p are constructed for both wavelength ranges. The distribution of the galaxies in these diagrams and systematic effects influencing estimation of the black-hole parameters are discussed. Upperenvelope cubic regression fits are obtained using the maximum estimates of the black-hole masses. The optical and radio upper envelopes show similar behavior, and have very similar peaks in position, zp1.9z_p \simeq 1.9, and amplitude, logMpbh\log M_p^{bh} = 9.4. This is consistent with a model in which the growth of the supermassive black holes is self-regulating, with this redshift corresponding to the epoch when the accretion-flow phase begins to end and the nuclear activity falls off.Comment: 8 pages, 6 figure
    corecore