Dr
Philippe Brax
(CEA-Saclay)
7/22/11, 9:00 AM
Parallel session talk
Despite more than 10 years of intense experimental and theoretical work, no plausible explanation to the acceleration
of the universe is available yet. Dark energy and modified gravity are two likely candidates. I will review their current status and state the problems that they both face. In particular, it turns out that at low energy both approaches reduce to scalar field models...
Dr
Delphine Hardin
(LPNHE)
7/22/11, 9:45 AM
Parallel session talk
We present the recent results from the analysis of the Supernova Legacy Survey 3-years data sample.
For the dark energy equation of state, assuming a flat universe, we measure a w parameter consistent with a cosmological constant
with a precision of 0.2. We have paid particular attention to the systematic uncertainties.
We combine the SNe data with baryon acoustic oscillation measurements...
Dr
Christophe Yeche
(IRFU-SPP / CEA-Saclay)
7/22/11, 11:00 AM
Parallel session talk
The SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), a five-year spectroscopic survey of 10,000 deg^2, achieved first light in late 2009. One of the key goals of BOSS is to measure the signature of baryon acoustic oscillations in the distribution of Ly-alpha absorption from the spectra of a sample of ~150,000 z>2.2 quasars. Along with measuring the angular diameter distance at...
Prof.
Michael Drinkwater
(University of Queensland)
7/22/11, 11:45 AM
Parallel session talk
The WiggleZ Dark Energy Survey on the Anglo-Australian Telescope has measured redshifts for 220,000 emission line galaxies. The galaxies sample a volume of 1 cubic Gpc and a redshift range of 0.2<z<1. This is the first survey to measure the cosmology of the universe over such a wide range of epochs. Our analysis provides strong evidence that dark energy is real.
In our first major...
Dr
Dominique Rebreyend
(LPSC/CNRS-IN2P3/UJF)
7/22/11, 12:30 PM
Parallel session talk
The GRANIT project is the follow-up of the pionnering experiments that first observed the quantum states of neutrons trapped in the earth’s gravitational field at the Institute Laue Langevin (ILL) [1]. Due to the weakness of the gravitational force, these quantum states exhibit most unusual properties: peV energies and spatial extensions of order 10 m. Whereas the first series of...
Dr
Christian Reichardt
(Dept. of Physics, University of California, Berkeley)
7/22/11, 2:30 PM
Parallel session talk
The South Pole Telescope (SPT) is a 10-meter telescope designed to survey the millimeter-wave sky. The telescope and its 960-element bolometric camera were successfully installed at the South Pole in 2007. Since then, the SPT has imaged 2200 square degrees of the sky with low noise and arcminute resolution. I will report on the CMB power spectrum results from SPT. In conjunction with data...
Guillaume Hurier
(LPSC)
7/22/11, 3:15 PM
Parallel session talk
The PLANCK mission will provide the most precise mesurement of the cosmic microwave background (CMB) anisotropies in temperature and polarization, allowing us to set tight constraints on the cosmological parameters. In addition, the PLANCK mission, because of its frequency coverage, is sensitive to the interaction of CMB photons and hot electrons in galaxy clusters via the thermal...
Benjamin Audren
(EPFL)
7/22/11, 3:35 PM
Parallel session talk
I will discuss the new numerical implementation in CLASS of two semi analytical methods for computing the matter power spectrum, namely the one-loop and Time Renormalization Group method. I will present our result compared against accurate N-body simulation and the halofit method on the BAO region. I will also discuss about the new implementation of the one-loop method, showing a great...
Dr
Luigi Pilo
(Department of Physics University of L'aquila)
7/22/11, 4:30 PM
Parallel session talk
In GR the static gravitational potential of a self-gravitating body goes as 1/r at large distances and any slower decrease leads to infinity energy. We show that in a class of four-dimensional massive gravity theories there exists spherically symmetric solutions with finite total energy, featuring an asymptotic behavior slower than 1/r and generically of the form $r^\gamma$. This suggests that...
Dr
Osamu Seto
(Hokka-Gakuen University)
7/22/11, 4:50 PM
Cosmology and Gravity
Parallel session talk
We show that in a class of two Higgs doublet model, where one Higgs doublet generates masses of quarks and charged leptons whereas the other Higgs doublet with a tiny vacuum expectation value generates neutrino Dirac masses, large Yukawa couplings lead to a large enough CP asymmetry of the right-handed neutrino decay. Thermal leptogenesis suitably works at low energy scale as keeping no...
Aurélien Barrau
(LPSC)
7/22/11, 5:10 PM
Parallel session talk
Loop Quantum Gravity is a very attractive attempt to perform a non-perturbative and background-independant quantization of general relativity. Applied to the Universe as a whole, the resulting framework, Loop Quantum Cosmology (LQC) has led to several important results beginning by the fact that the Big Bang singularity is resolved and replaced by a Big Bounce. In this talk, I will focus on...
Ms
alexia gorecki
(LPSC)
7/22/11, 5:30 PM
Cosmology and Gravity
Parallel session talk
The Large Synoptic Survey Telescope (LSST) system will produce a 6-band wide and deep field astronomical survey of over 20,000 square degrees of the southern sky using an 8.4-meter ground-based telescope. Each patch of sky will be visited about 1000 times in ten years.
Its camera will be the world largest one, with 3200 Megapixels. It will cover a huge 9.6 square degree field of view, and...
Ignacio Sevilla
(CIEMAT, Madrid)
7/22/11, 5:50 PM
Parallel session talk
The Dark Energy Survey will employ a powerful instrument, the Dark Energy Camera, and a state-of-the-art data management system on the improved Blanco 4-meter telescope at CTIO to probe the nature of dark energy and the cause of cosmic acceleration. The instrument includes a 520-Megapixel optical imager with red-sensitive CCDs covering a 3 square degree field of view and an active alignment...
nicolas Chotard
(Institut de physique nucléaire de Lyon)
7/22/11, 6:10 PM
Parallel session talk
Type Ia supernovae (SNe~Ia) are used as standard candles to measure the history of the universe expansion. However, precise measurements need an empirical standardization of the luminosities usually done with two light-curve derived parameters (stretch and color): brighter SNe~Ia exhibit a broader light curve, and redder objects are fainter. Employing the flux calibrated spectra sample...
