http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Cosmic voids in Sloan Digital Sky Survey Data Release 7
Pan, Danny C.,Vogeley, Michael S.,Hoyle, Fiona,Choi, Yun‐,Young,Park, Changbom Blackwell Publishing Ltd 2012 Monthly notices of the Royal Astronomical Society Vol.421 No.2
<P><B>ABSTRACT</B></P><P>We study the distribution of cosmic voids and void galaxies using Sloan Digital Sky Survey Data Release 7 (SDSS DR7). Using the VoidFinder algorithm based on the original VoidFinder method devised by El‐Ad & Piran and implemented by Hoyle & Vogeley, we identify 1054 statistically significant voids in the Northern galactic hemisphere with radii > 10 <I>h</I><SUP>−1</SUP> Mpc. The filling factor of voids in the sample volume is 62 per cent. The largest void is just over 30 <I>h</I><SUP>−1</SUP> Mpc in effective radius. The median effective radius is 17 <I>h</I><SUP>−1</SUP> Mpc. The voids are found to be significantly underdense, with density contrast δ < − 0.85 at the edges of the voids. The radial‐density profiles of these voids are similar to predictions of dynamically distinct underdensities in gravitational theory. We find 8046 galaxies brighter than <I>M<SUB>r</SUB></I>=− 20.09 within the voids, accounting for 7 per cent of the galaxies. We compare the results of VoidFinder on SDSS DR7 to mock catalogues generated from a smoothed particle hydrodynamics (SPH) halo model simulation as well as other Λ cold dark matter (ΛCDM) simulations and find similar void fractions and void sizes in the data and simulations. This catalogue is made publicly available at http://www.physics.drexel.edu/~pan/VoidCatalog for download.</P>
A TOPOLOGICAL ANALYSIS OF LARGE-SCALE STRUCTURE, STUDIED USING THE CMASS SAMPLE OF SDSS-III
Parihar, Prachi,Vogeley, Michael S.,Gott III, J. Richard,Choi, Yun-Young,Kim, Juhan,Kim, Sungsoo S.,Speare, Robert,Brownstein, Joel R.,Brinkmann, J. IOP Publishing 2014 The Astrophysical journal Vol.796 No.2
<P>We study the three-dimensional genus topology of large-scale structure using the northern region of the CMASS Data Release 10 (DR10) sample of the SDSS-III Baryon Oscillation Spectroscopic Survey. We select galaxies with redshift 0.452 < z < 0.625 and with a stellar mass M-stellar > 10(11.56) M-circle dot. We study the topology at two smoothing lengths: R-G = 21 h(-1) Mpc and R-G = 34 h(-1) Mpc. The genus topology studied at the R-G = 21 h(-1) Mpc scale results in the highest genus amplitude observed to date. The CMASS sample yields a genus curve that is characteristic of one produced by Gaussian random phase initial conditions. The data thus support the standard model of inflation where random quantum fluctuations in the early universe produced Gaussian random phase initial conditions. Modest deviations in the observed genus from random phase are as expected from shot noise effects and the nonlinear evolution of structure. We suggest the use of a fitting formula motivated by perturbation theory to characterize the shift and asymmetries in the observed genus curve with a single parameter. We construct 54 mock SDSS CMASS surveys along the past light cone from the Horizon Run 3 (HR3) N-body simulations, where gravitationally bound dark matter subhalos are identified as the sites of galaxy formation. We study the genus topology of the HR3 mock surveys with the same geometry and sampling density as the observational sample and find the observed genus topology to be consistent with ACDM as simulated by the HR3 mock samples. We conclude that the topology of the large-scale structure in the SDSS CMASS sample is consistent with cosmological models having primordial Gaussian density fluctuations growing in accordance with general relativity to form galaxies in massive dark matter halos.</P>