A. Ealet, S. Escoffier, D. Fouchez, F. Henry-Couannier, S. Kermiche, C. Tao, A. Tilquin September 2012

In 1998, observation of distant supernovae suggested that the expansion of the Universe is accelerating Nobel Prize in Physics in 2011 S. Perlmutter, B. Schmidt, A. Riess Total mass-energy of the Universe is dominated by a cosmic fluid called dark energy in opposition to the attractive force of matter

This descriptive scheme of the Universe has been confirmed by several other cosmological probes as the Cosmic Microwave Background (CMB) and the galaxy clustering with Baryon Acoustic Oscillations (BAO) The standard model of cosmology is called the Concordance Model

The concordance model = ΛCDM where Λ is the cosmological constant and CDM the Cold Dark Matter 73% dark energy 23% dark matter 4% ordinary matter The concordance model = ΛCDM where Λ is the cosmological constant and CDM the Cold Dark Matter 73% dark energy 23% dark matter 4% ordinary matter Another interpretations are:  quintessence  deviation from General Relativity  Homogeneity assumption However the nature of dark energy is still unknown

The cosmology group at CPPM undertakes research in a wide range of topics in cosmology. It is also involved in several projects:  Supernovae projects such as SNLS (distant SNe) and SNFactory (nearby SNe)  Baryon Acoustic Oscillation (BAO) with BOSS on SDSS-III Projects with data collection and analysis in progress Future surveys  the LSST ground based telescope (first light planned for 2020)  the Euclid space mission selected by ESA (launch in 2020) Combined analysis  Dev. of analysis tools for the extraction of cosmological parameters from combination of several probes (SNe, BAO, CMB,..) (includes collaborations with CPT & LAM)

Overview of past and present projects Equation of state w= p/ρ Combination SN/CMB/BAO Flat Universe w= ± (stat) ± 0.061(syst) No Flat Universe w= ± 0.06 (stat) ± 0.075(syst) (If cosmological constant then w=-1) Equation of state w= p/ρ Combination SN/CMB/BAO Flat Universe w= ± (stat) ± 0.061(syst) No Flat Universe w= ± 0.06 (stat) ± 0.075(syst) (If cosmological constant then w=-1) Supernovae are standard candles

Distant supernovae (z>0.3) with SNLS: - Observation of ~700 SN at the CFHT, photometric and spectroscopic follow-up - Collaboration France/canada/US - Definitive results expected soon Distant supernovae (z>0.3) with SNLS: - Observation of ~700 SN at the CFHT, photometric and spectroscopic follow-up - Collaboration France/canada/US - Definitive results expected soon Nearby supernovae (z<0.1) with SNFactory : - Zero Point for the cosmology - Study of systematics for standardization, variability, explosion models, … Nearby supernovae (z<0.1) with SNFactory : - Zero Point for the cosmology - Study of systematics for standardization, variability, explosion models, …

To test gravity = need for other probes The large-scale distribution of galaxies probes the primordial density fluctuations of the Universe To test gravity = need for other probes The large-scale distribution of galaxies probes the primordial density fluctuations of the Universe First detection of the BAO in the SDSS-II survey in 2005 BAO is the imprint of primordial fluctuations in the galaxy distribution BAO feature is a standard ruler

Extraction of the BAO with SDSS III/BOSS:  Started data collection in 2009 for 5 years  1.5 Millions Luminous Red Galaxies (z< 0.7) on 10,000 deg2 (spectro)  QSOs at 2 <z< 4  Expected measurement precision (stat) dw ~ 0.08 (only) et 0.04 (combined) Extraction of the BAO with SDSS III/BOSS:  Started data collection in 2009 for 5 years  1.5 Millions Luminous Red Galaxies (z< 0.7) on 10,000 deg2 (spectro)  QSOs at 2 <z< 4  Expected measurement precision (stat) dw ~ 0.08 (only) et 0.04 (combined) - US project with French Participation - A lot of data to analyze - Collaborations with CPT and LAM extended-BOSS expected for

Combination of data from different cosmological probes (frequentist approach)  Original statistical tool dev. on the CPPM grid combination of SNe + CMB + BAO + WL  Collaboration with CPT/LAM/Saclay  Collaboration with China Several publications 2 PhD on this topic (2009)

Ground based telescope LSST Dedicated 8 meter telescope Space Euclid mission CPPM - Implication in the filter system - Preparation of data analysis - Simulation, specifications and optimization LSST will provide multiple probes of dark energy (SN, WL, BAO, clusters) Approved by ESA in 2011 CPPM - Implication in the NISP instrument - Preparation of data analysis - Simulation, IR detectors and calibration Euclid will provide multiple probes of dark energy (WL, BAO, clusters)

Composition: Permanent staff: 7 researchers (CNRS, University) Non-permanent staff: 1 student in 3 rd year (Euclid) 1 student in 1 st year (Euclid) 2 postdocs on Euclid 1 postdoc on BOSS (7 PhD defended since 2004)  Need PhD students on SNe / BAO

Contact:A. Ealet S. Escoffier Seminars (1 st semester) and computer projects (2 nd semester) will be proposed by the RENOIR team Research internship (2 nd semester) followed by a PhD thesis will be proposed on: - SNe with SNFactory/LSST - BAO with BOSS