COSMOLOGY: OBSERVATIONS

A Near-infrared Period-Luminosity Relation for Miras in NGC 4258, an Anchor for a New Distance Ladder

We present year-long, near-infrared (NIR) Hubble Space Telescope (HST) WFC3 observations of Mira variables in the water megamaser host galaxy NGC 4258. Miras are asymptotic giant branch variables that can be divided into oxygen- (O-) and carbon- (C-) …

CfAIR2: Near-infrared Light Curves of 94 Type Ia Supernovae

CfAIR2 is a large, homogeneously reduced set of near-infrared (NIR) light curves (LCs) for Type Ia supernovae (SNe Ia) obtained with the 1.3 m Peters Automated InfraRed Imaging TELescope. This data set includes 4637 measurements of 94 SNe Ia and 4 …

Berkeley Supernova Ia Program - I. Observations, data reduction and spectroscopic sample of 582 low-redshift Type Ia supernovae

In this first paper in a series, we present 1298 low-redshift (z łesssim 0.2) optical spectra of 582 Type Ia supernovae (SNe Ia) observed from 1989 to 2008 as part of the Berkeley Supernova Ia Program (BSNIP). 584 spectra of 199 SNe Ia have …

Afterglow Observations of Fermi Large Area Telescope Gamma-ray Bursts and the Emerging Class of Hyper-energetic Events

We present broadband (radio, optical, and X-ray) light curves and spectra of the afterglows of four long-duration gamma-ray bursts (GRBs GRBs 090323, 090328, 090902B, and 090926A) detected by the Gamma-Ray Burst Monitor and Large Area Telescope (LAT) …

Improved Standardization of Type II-P Supernovae: Application to an Expanded Sample

In the epoch of precise and accurate cosmology, cross-confirmation using a variety of cosmographic methods is paramount to circumvent systematic uncertainties. Owing to progenitor histories and explosion physics differing from those of Type Ia …

Generalized Tests for Selection Effects in Gamma-Ray Burst High-Energy Correlations

Several correlations among parameters derived from modeling the high- energy properties of gamma-ray bursts (GRBs) have been reported. We show that well known examples of these have common features indicative of strong contamination by selection …

Toward a More Standardized Candle Using Gamma-Ray Burst Energetics and Spectra

The use of gamma-ray burst (GRB) energetics for cosmography has long been advanced as a means to probe out to high redshifts, to the epoch of deceleration. However, although relatively immune to systematic biases from dust extinction, the prompt …

Optical Limits on Precursor Emission from Gamma-Ray Bursts with Known Redshift

Making use of virtual observatory data, we present the first comprehensive sample of optical observations conducted before the explosion times of all gamma-ray bursts (GRBs) with known redshifts. In total, the fields of 11 such GRBs were observed by …

Gamma-Ray Burst Energetics and the Gamma-Ray Burst Hubble Diagram: Promises and Limitations

We present a complete sample of 29 gamma-ray bursts (GRBs) for which it has been possible to determine temporal breaks (or limits) from their afterglow light curves. We interpret these breaks within the framework of the uniform conical jet model, …

The Redshift and the Host Galaxy of GRB 980613: A Gamma-Ray Burst from a Merger-induced Starburst?

We present the optical and near-IR identification and spectroscopy of the host galaxy of gamma-ray burst GRB 980613. The burst was apparently associated with the optically (rest-frame UV) brightest component of an apparent system of at least five …