Susana Elizabeth Deustua

Discovery of a supernova explosion at half the age of the universe

The ultimate fate of the Universe, infinite expansion or a big crunch, can be determined by using the redshifts and distances of very distant supernovae to monitor changes in the expansion rate. We can now find large numbers of these distant supernovae, and measure their redshifts and apparent brightnesses; moreover, recent studies of nearby type Ia supernovae have shown how to determine their intrinsic luminosities—and therefore with their apparent brightnesses obtain their distances. The >50 distant supernovae discovered so far provide a record of changes in the expansion rate over the past several billion years. However, it is necessary to extend this expansion history still farther away (hence further back in time) in order to begin to distinguish the causes of the expansion-rate changes—such as the slowing caused by the gravitational attraction of the Universes mass density, and the possibly counteracting effect of the cosmological constant. Here we report the most distant spectroscopically confirmed supernova. Spectra and photometry from the largest telescopes on the ground and in space show that this ancient supernova is strikingly similar to nearby, recent type Ia supernovae. When combined with previous measurements of nearer supernovae,, these new measurements suggest that we may live in a low-mass-density universe.

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

The Hubble Space Telescope Cluster Supernova Survey. V. Improving the Dark-energy Constraints above z > 1 and Building an Early-type-hosted Supernova Sample

\Omega_M

Spectra and hubble space telescope light curves of six typE Ia supernovae at 0.511 < z < 1.12 and the union2 compilation

,

Multiwavelength Observations of Flares on AD Leonis

\Omega_\Lambda

PROBING FOR EVIDENCE OF PLUMES ON EUROPA WITH HST/STIS

, 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

Radio and optical observations of 0218+357 - The smallest Einstein ring?

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

Detection of a High Brightness Temperature Radio Core in the Active-galactic-nucleus-driven Molecular Outflow Candidate NGC 1266

(statistical)

Quantitative comparison between Type Ia supernova spectra at low and high redshifts: A case study

\pm0.04

Spectra of High-Redshift Type Ia Supernovae and a Comparison with Their Low-Redshift Counterparts*

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