618 research outputs found

    On the Mass Eigenstate Composition of the 8B Neutrinos from the Sun

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    The present data of gallium experiments provide indirectly the only experimental limit on the fraction of ν2\nu_2 mass eigenstate for the 8^8B neutrinos from the Sun. However, if to use the experimental data alone, the fraction of ν2\nu_2 and, consequently, sin2θsolsin^2\theta_{sol} still is allowed to be varied within a rather broad range. The further experimental efforts are needed to clear this point.Comment: 13 pages, 1 figure, 1 table. Corrected version, published in JCAP04(2007)00

    Imaging Three Dimensional Two-particle Correlations for Heavy-Ion Reaction Studies

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    We report an extension of the source imaging method for analyzing three-dimensional sources from three-dimensional correlations. Our technique consists of expanding the correlation data and the underlying source function in spherical harmonics and inverting the resulting system of one-dimensional integral equations. With this strategy, we can image the source function quickly, even with the finely binned data sets common in three-dimensional analyses.Comment: 13 pages, 11 figures, submitted to Physical Review

    A Lithium Experiment in the Program of Solar Neutrino Research

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    The experiments sensitive to pp-neutrinos from the Sun are very perspective for the precise measurement of a mixing angle θ12\theta_{12}. A ν\nu e−^{-} scattering experiment (Xmass) and/or a charged-current experiment (the indium detector) can measure the flux of electron pp-neutrinos. One can find the total flux of pp-neutrinos from a luminosity constraint after the contribution of 7^7Be and CNO neutrinos to the total luminosity of the Sun are measured. The radiochemical experiment utilizing a lithium target has the high sensitivity to the CNO neutrinos, thus, it has a good promise for the precise measurement of a mixing angle and for the test of a current theory of the evolution of the stars.Comment: 6 pages, 2 figures, 1 table, A report made by A.Kopylov at International Conference NANP-2005, June 2005, Dubna, Russi

    VV124 (UGC4879): A new transitional dwarf galaxy in the periphery of the Local Group

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    We present the first resolved-star photometry of VV124 (UGC4879) and find that this is the most isolated dwarf galaxy in the periphery of the Local Group. Based on imaging and spectroscopic follow up observations with the 6m BTA telescope, we resolve VV124 into 1560 stars down to the limiting magnitude levels of V~25.6 and I~23.9. The young blue stellar populations and emission gas are found near the core, but noticeably displaced from the center of the galaxy as traced by dominant evolved red stars. The mean radial velocity derived from the spectra of two Blue Supergiant stars, an HII region and unresolved continuum sources is -80+/-10 km/s. The evolved ``red tangle'' stellar populations, which contains the red giant branch (RGB), are identified at large galactocentric radii. We use the I-band luminosity function to determine the distance based on the Tip of RGB method, 1.1+/-0.1 Mpc. This is ~10 times closer than the values usually assumed in the literature, and we provide revised distance dependent parameters. From the mean (V-I) color of the RGB, we estimate the mean metallicity as [Fe/H]~-1.37 dex. Despite of its isolated location, the properties of VV124 are clearly not those of a galaxy in formation, but rather similar to a transitional dIrr/dSph type.Comment: 4 pages, submitted to MNRAS Letter

    RC J1148+0455 identification: gravitational lens or group of galaxies ?

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    The structure of the radio source RC B1146+052 of the ``Cold'' catalogue is investigated by data of the MIT-GB-VLA survey at 4850 MHz. This source belongs to the steep spectrum radio sources subsample of the RC catalogue. Its spectral index is α\alpha = -1.04. The optical image of this source obtained with 6m telescope is analysed. The radio source center is situated in a group of 8 galaxies of about 24m^m in the R-filter. The possible explanations of the complex structure of radio components are considered.Comment: 6 pages, 5 figures, uses psfig.sty. This was the poster as presented on Gamow Memorial Internat. Conference GMIC'99 "Early Universe: Cosmological Problems and Instrumental Technologies" in St.Petersburg, 23-27 Aug., 1999. Submitted to Proceedings to be published in A&A Transaction

    Optical morphology of distant RATAN-600 radio galaxies from subarcsecond resolution NOT images

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    We present direct imaging data of 22 ultra steep spectrum radio sources obtained at (or near) a subarcsecond seeing. The basic sample of 40 double radio sources was selected from the RATAN-600 catalogue. The FRII-structure has been confirmed with VLA and preliminary optical identifications which come from the 6 m-telescope. As the RATAN-600 flux limit at 3.9 GHz (≈\approx 10mJy) is fainter than that of major surveys, the sample may have high-zz contents. This is also suggested by the faint magnitudes in the Hubble diagram. The final aim is to create a homogeneous sample of high-zz radio galaxies in a well defined strip around the sky, with faint radio limit and subarcsecond morphology down to mR=24m_{R}=24. We could confirm 16 identifications down to mR∼m_{R}\sim24. Most of the extended objects have multicomponent structures as expected from other surveys of high-redshift radio galaxies. We found five unresolved objects even with a subarcsecond seeing. Of the remaining six objects, three are extremely faint and the other three have such a complex environment that further observations are needed to confirm the optical identification.Comment: A&AS in pres
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