### Browsing by Subject "general physics"

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- ItemOpen AccessA more general model for the intrinsic scatter in type Ia supernova distance moduli(2011) Marriner, John; Bernstein, J P; Kessler, Richard; Lampeitl, Hubert; Miquel, Ramon; Mosher, Jennifer; Nichol, Robert C; Sako, Masao; Schneider, Donald P; Smith, MathewWe describe a new formalism to fit the parameters {alpha} and {beta} that are used in the SALT2 model to determine the standard magnitudes of Type Ia supernovae (SNe Ia). The new formalism describes the intrinsic scatter in SNe Ia by a covariance matrix in place of the single parameter normally used. We have applied this formalism to the Sloan Digital Sky Survey Supernova Survey (SDSS-II) data and conclude that the data are best described by {alpha} = 0.135{sup +.033} - .017 and {beta} = 3.19{sup +0.14} - 0.24, where the error is dominated by the uncertainty in the form of the intrinsic scatter matrix. Our result depends on the introduction of a more general form for the intrinsic scatter of the distance moduli of SNe Ia than is conventional, resulting in a larger value of {beta} and a larger uncertainty than the conventional approach. Although this analysis results in a larger value of {beta} and a larger error, the SDSS data differ (at a 98% confidence level) from {beta} = 4.1, the value expected for extinction by the type of dust found in the Milky Way. We have modeled the distribution of SNe Ia in terms of their colormore » and conclude that there is strong evidence that variation in color is a significant contributor to the scatter of SNe Ia around their standard candle magnitude.« less
- ItemOpen AccessComplex statistics and diffusion in nonlinear disordered particle chains(2014) Antonopoulos, Ch G; Bountis, T; Skokos, Ch; Drossos, LWe investigate dynamically and statistically diffusive motion in a Klein-Gordon particle chain in the presence of disorder. In particular, we examine a low energy (subdiffusive) and a higher energy (self-trapping) case and verify that subdiffusive spreading is always observed. We then carry out a statistical analysis of the motion in both cases in the sense of the Central Limit Theorem and present evidence of different chaos behaviors, for various groups of particles. Integrating the equations of motion for times as long as $109$, our probability distribution functions always tend to Gaussians and show that the dynamics does not relax onto a quasi-periodic KAM torus and that diffusion continues to spread chaotically for arbitrarily long times.
- ItemOpen AccessCosmological constraints from the SDSS luminous red galaxies(2006) Tegmark, Max; Eisenstein, Daniel J; Strauss, Michael A; Weinberg, David H; Blanton, Michael R; Frieman, Joshua A; Fukugita, Masataka; Gunn, James E; Hamilton, Andrew J S; Knapp, Gillian R; Nichol, Robert C; Ostriker, Jeremiah P; Padmanabhan, Nikhil; Percival, Will J; Schlegel, David J; Schneider, Donald P; Scoccimarro, Roman; Seljak, Uroš; Seo, Hee-Jong; Swanson, Molly; Szalay, Alexander S; Vogeley, Michael S; Yoo, Jaiyul; Zehavi, Idit; Abazajian, Kevork; Anderson, Scott F; Annis, James; Bahcall, Neta A; Bassett, Bruce; Berlind, Andreas; Brinkmann, Jon; Budavári, TamásNo abstract prepared.
- ItemOpen AccessImproved constraints on type Ia supernova host galaxy properties using multi-wavelength photometry and their correlations with supernova properties(2011) Gupta, Ravi R; D’Andrea, Chris B; Sako, Masao; Conroy, Charlie; Smith, Mathew; Bassett, Bruce; Frieman, Joshua A; Garnavich, Peter M; Jha, Saurabh W; Kessler, Richard; Lampeitl, Hubert; Marriner, John; Nichol, Robert C; Schneider, Donald PWe improve estimates of the stellar mass and mass-weighted average age of Type Ia supernova (SN Ia) host galaxies by combining UV and near-IR photometry with optical photometry in our analysis. Using 206 SNe Ia drawn from the full three-year Sloan Digital Sky Survey (SDSS-II) Supernova Survey (median redshift of z 0.2) and multi-wavelength host-galaxy photometry from SDSS, the Galaxy Evolution Explorer, and the United Kingdom Infrared Telescope Infrared Deep Sky Survey, we present evidence of a correlation (1.9σ confidence level) between the residuals of SNe Ia about the best-fit Hubble relation and the mass-weighted average age of their host galaxies. The trend is such that older galaxies host SNe Ia that are brighter than average after standard light-curve corrections are made. We also confirm, at the 3.0σ level, the trend seen by previous studies that more massive galaxies often host brighter SNe Ia after light-curve correction.