Concordance of the Dirac-Milne universe

Abstract:
« The Dirac-Milne universe, a matter-antimatter universe where antimatter
has a negative gravitational mass, presents several elements
of concordance with our universe, except apparently for two tests:
primordial helium-3, and BAO, at least if the latter is interpreted in a
conventional way.
After a discussion on the definition of a negative mass particle,
I will describe the formation of structures in the Dirac-Milne universe,

Colloquium APC : résultats de Gravity

Extended Cosmo Group Meeting

Kinetic Inductance Detectors (KIDs)

Kinetic inductance detector (KID) is a promising technology for astronomy with high sensitivity, microsecond timing and intrinsic multiplexing readout properties. Based on these advantages, a wide range of application has been proposed from millimeter to X-ray. With simple fabrication and frequency domain multiplexing readout, hundreds of KID pixels could be easily read out with single cable. In the last decade, KID has been developed rapidly. This talk will introduce the recent development of KIDs for frequency range from 100 GHz to 1 THz.

Studying black hole populations with gravitational-wave observations

The first observations of gravitational waves emitted by merging binary black holes demonstrated the existence of black holes more massive than ever observed in our Galaxy. Future observations with ground-based interferometers such as Advanced LIGO and Virgo will probe the mass and spin distributions of black holes in various galactic environments and may also detect the stochastic gravitational-wave background from unresolved mergers. These measurements will provide a new tool for stellar and galaxy evolution studies.

Physics of Gravitational Redshifts in Clusters of Galaxies

Wojtak, Hansen and Hjorth and others have measured the long-predicted gravitational redshift of light escaping from galaxy clusters. The effect is very small, corresponding to a velocity shift of only ~10 km/s, but the result appears to be fairly robust and seemed to be in good agreement with general relativity predictions and possibly in conflict with some alternative theories. The effect was initially imagined to be a simple astronomical analogue of the famous terrestrial Pound and Rebka experiment that verified Einstein's theoretical prediction.

Weak Lensing Peak Counts and New Statistical Methods

Martin Kilbinger (CEA) will speak with us about weak-lensing peak counts, and a new statistical method that he has been using lately called Approximate Bayesian Computation (ABC). This is a likelihood-free parameter inference technique which is gaining popularity in cosmology, so it might be interesting for a wider audience than just weak lensing.

The Dark Energy Survey Supernova Program and the Australian OzDES survey

The Dark Energy Survey (DES) is using four probes to investigate the dynamics of the expansion of the Universe. The DES Supernova Program (DES-SN) is observing 27 square degrees with a 6-day cadence to obtain a large sample of type Ia supernovae for cosmology. In collaboration with DES, OzDES is using the AAT to obtain redshifts and classifications for objects in the DES fields.

LABORATOIRE

ASTROPARTICULE & COSMOLOGIE

Cosmologie

Colloquium APC