Distance Measurements from Supernovae and Dark Energy Constraints

Abstract

Constraints on dark energy from current observational data are sensitive to how distances are measured from Type Ia supernova (SN Ia) data. We find that flux-averaging of SNe Ia can be used to test the presence of unknown systematic uncertainties, and yield more robust distance measurements from SNe Ia. We have applied this approach to the nearby + SDSS +ESSENCE +SNLS +HST set of 288 SNe Ia, and the ``Constitution''of set 397 SNe Ia. Combining the SN Ia data with CMB data from WMAP five year observations, the Sloan Digital Sky Survey baryon acoustic oscillation measurements, the data of 69 gammay-ray bursts, and the Hubble constant measurement from the HST project SHOES, we measure the dark energy density function X(z)=ρ_X(z)/ρ_X(0) as a free function of redshift (assumed to be a constant at z>1 or z>1.5). Without flux-averaging of SNe Ia, the combined data using the ``Constitution'' set of SNe Ia seem to indicate a deviation from a cosmological constant at ~95% confidence level at 0< z <0.8; they are consistent with a cosmological constant at ~68% confidence level when SNe Ia are flux-averaged. The combined data using the nearby +SDSS +ESSENCE +SNLS +HST data set of SNe Ia are consistent with a cosmological constant at 68% confidence level with or without flux-averaging of SNe Ia, and give dark energy constraints that are significantly more stringent than that using the ``Constitution'' set of SNe Ia. Assuming a flat universe, dark energy is detected at >98% confidence level for z<= 0.75 using the combined data with 288 SNe Ia from nearby + SDSS+ ESSENCE +SNLS +HST, independent of the assumptions about X(z>1). We quantify dark energy constraints without assuming a flat universe using the dark energy Figure-of-Merit (FoM) for both $X(z)$ and a dark energy equation-of-state linear in the cosmic scale factor.

12 pages including 12 figures. Slightly expanded version accepted by PRD

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• Deviation from the Cosmological Constant or Systematic Errors?
• Inference for the dark energy equation of state using Type IA supernova data

Cited by in corpus (24)

• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Dark Energy
• Holographic Dark Energy
• Notes on Ghost Dark Energy
• Designing a space-based galaxy redshift survey to probe dark energy
• A model independent null test on the cosmological constant
• Cosmological constraints on extended Galileon models
• Robust and model-independent cosmological constraints from distance measurements
• Constraints on Cosmological Models and Reconstructing the Acceleration History of the Universe with Gamma-Ray Burst Distance Indicators
• Exploring the Systematic Uncertainties of Type Ia Supernovae as Cosmological Probes
• A Comparative Study of Dark Energy Constraints from Current Observational Data
• Exploring the Latest Union2 SNIa Dataset by Using Model-Independent Parametrization Methods
• Probing Dark Energy Dynamics from Current and Future Cosmological Observations
• Probing the dynamical behavior of dark energy
• A Robust Distance Measurement and Dark Energy Constraints from the Spherically-Averaged Correlation Function of Sloan Digital Sky Survey Luminous Red Galaxies
• Exploring the cosmological consequences of JLA supernova data with improved flux-averaging technique
• Comparing dark energy models with current observational data
• Figure of Merit and Different Combinations of Observational Data Sets
• Analysis of recent type Ia supernova data based on evolving dark energy models
• Genetic algorithms and the analysis of SnIa data
• Probing Cosmic Acceleration by Using Model-Independent Parametrizations and Three Kinds of Supernova Statistics Techniques
• Constraints of Dark Energy at High Redshift
• Dynamical analysis of $k$-essence cosmology in the light of Supernova Ia observations
• Kinematic reconstruction of torsion as dark energy in Friedmann cosmology