Search Publications
Confronting brane inflation with Planck and pre-Planck data
Zhang, Xin; Huang, Qing-Guo; Ma, Yin-Zhe
In this paper, we compare brane inflation models with the Planck data and the pre-Planck data (which combines WAMP, ACT, SPT, BAO and H0 data). The Planck data prefer a spectral index less than unity at more than 5σ confidence level, and a running of the spectral index at around 2σ confidence level. We find that the KKLMMT model can sur…
Gas Density Profile in Dark Matter Halo in Chameleon Cosmology
Terukina, Ayumu; Yamamoto, Kazuhiro
We investigate the gas density, temperature, and pressure profiles in a dark matter halo under the influence of the chameleon force. We solve the hydrostatic equilibrium equation for the gas coupled with the chameleon field in an analytic manner, using an approximate solution for the chameleon field equation with the source term, with a generalize…
Sunyaev-Zel'dovich signal of the maxBCG SDSS galaxy clusters in WMAP
Rozo, Eduardo; Hao, Jiangang; Dodelson, Scott +1 more
The Planck Collaboration measured the Sunyaev-Zel’dovich decrement of optically selected clusters from the Sloan Digital Sky Survey, finding that it falls significantly below expectations based on existing mass calibration of the maxBCG galaxy clusters. Resolving this tension requires either the data to go up, or the theoretical expectations to co…
Constraints on non-Gaussianity from Sunyaev-Zeldovich cluster surveys
Mak, Daisy S. Y.; Pierpaoli, Elena
We perform a Fisher matrix analysis to forecast the capability of ongoing and future Sunyaev-Zeldovich cluster surveys in constraining the deviations from Gaussian distribution of primordial density perturbations. We use the constraining power of the cluster number counts and clustering properties to forecast limits on the fNL parameter…
Cold positrons from decaying dark matter
Boubekeur, Lotfi; Dodelson, Scott; Vives, Oscar
Many models of dark matter contain more than one new particle beyond those in the Standard Model. Often, heavier particles decay into the lightest dark matter particle as the Universe evolves. Here, we explore the possibilities which arise if one of the products in a (heavyparticle)→(darkmatter) decay is a positron, and the lifetime is shorter tha…
Amplitudes of thermal and kinetic Sunyaev-Zel'dovich signals from small-scale CMB anisotropies
Melchiorri, Alessandro; Cooray, Asantha; Pagano, Luca +4 more
While the arcminute-scale cosmic microwave background (CMB) anisotropies are due to secondary effects, point sources dominate the total anisotropy power spectrum. At high frequencies the point sources are primarily in the form of dusty, star-forming galaxies. Both Herschel and Planck have recently measured the anisotropy power spectrum of cosmic i…
Constraints on Lorentz Invariance Violation using integral/IBIS observations of GRB041219A
Covino, S.; Götz, D.; Laurent, P. +2 more
One of the experimental tests of Lorentz invariance violation is to measure the helicity dependence of the propagation velocity of photons originating in distant cosmological obejcts. Using a recent determination of the distance of the gamma-ray burst GRB 041219A, for which a high degree of polarization is observed in the prompt emission, we are a…
Metastable dark matter mechanisms for INTEGRAL 511 keV γ rays and DAMA/CoGeNT events
Cline, James M.; Chen, Fang; Frey, Andrew R.
We explore dark matter mechanisms that can simultaneously explain the galactic 511 keV gamma rays observed by INTEGRAL/SPI, the DAMA/LIBRA annual modulation, and the excess of low-recoil dark matter candidates observed by CoGeNT. It requires three nearly degenerate states of dark matter in the 4-7 GeV mass range, with splittings, respectively, of …
Search for cosmic strings in the COSMOS survey
Smoot, G. F.; Christiansen, J. L.; Albin, E. +4 more
We search the COSMOS survey for pairs of galaxies consistent with the gravitational lensing signature of a cosmic string. The COSMOS survey imaged 1.64 square degrees using the Advanced Camera for Surveys aboard the Hubble Space Telescope. Our technique includes estimates of the efficiency for finding the lensed galaxy pair. We find no evidence fo…
Real space CMB lensing reconstruction with point source masks
Carvalho, C. Sofia; Tereno, Ismael
An incomplete sky coverage poses difficulties in the extraction of the weak lensing information from the CMB. We test the reconstruction of the weak lensing convergence from CMB maps to which masks of point sources have been applied. We use the quadratic estimator with a kernel with finite support acting in real space for a Planck simulation. We r…