Ariel Goobar

Measurements of Omega and Lambda from 42 high redshift supernovae

We report measurements of the mass density, Omega_M, and cosmological-constant energy density, Omega_Lambda, of the universe based on the analysis of 42 Type Ia supernovae discovered by the Supernova Cosmology Project. The magnitude-redshift data for these SNe, at redshifts between 0.18 and 0.83, are fit jointly with a set of SNe from the Calan/Tololo Supernova Survey, at redshifts below 0.1, to yield values for the cosmological parameters. All SN peak magnitudes are standardized using a SN Ia lightcurve width-luminosity relation. The measurement yields a joint probability distribution of the cosmological parameters that is approximated by the relation 0.8 Omega_M - 0.6 Omega_Lambda ~= -0.2 +/- 0.1 in the region of interest (Omega_M 0) = 99%, including the identified systematic uncertainties. The best-fit age of the universe relative to the Hubble time is t_0 = 14.9{+1.4,-1.1} (0.63/h) Gyr for a flat cosmology. The size of our sample allows us to perform a variety of statistical tests to check for possible systematic errors and biases. We find no significant differences in either the host reddening distribution or Malmquist bias between the low-redshift Calan/Tololo sample and our high-redshift sample. The conclusions are robust whether or not a width-luminosity relation is used to standardize the SN peak magnitudes.

New constraints on Omega(M), Omega(lambda), and w from an independent set of eleven high-redshift supernovae observed with HST

We report measurements of

Measurements of the cosmological parameters omega and lambda from the first seven supernovae at z greater than or equal to 0.35

Omega_M

A strong ultraviolet pulse from a newborn type Ia supernova

,

A Supernova at z = 0.458 and Implications for Measuring the Cosmological Deceleration

Omega_Lambda

Erratum: Discovery of a supernova explosion at half theage of the Universe

, and w from eleven supernovae at z=0.36-0.86 with high-quality lightcurves measured using WFPC-2 on the HST. This is an independent set of high-redshift supernovae that confirms previous supernova evidence for an accelerating Universe. Combined with earlier Supernova Cosmology Project data, the new supernovae yield a flat-universe measurement of the mass density

Implications for the Hubble Constant from the First Seven Supernovae at [CLC][ITAL]z[/ITAL][/CLC] ≥ 0.35

Omega_M=0.25^{+0.07}_{-0.06}

Early Observations of the Type Ia Supernova iPTF 16abc: A Case of Interaction with Nearby, Unbound Material and/or Strong Ejecta Mixing

(statistical)

Erratum: A strong ultraviolet pulse from a newborn type Ia supernova

pm0.04

Discovery of the Most Distant Supernovae and the Quest for Omega

(identified systematics), or equivalently, a cosmological constant of