Current Research

Pan-STARRS -- the Panoramic Survey Telescope & Rapid Response System

Pan-STARRS -- the Panoramic Survey Telescope & Rapid Response System -- is an innovative design for a wide-field imaging facility being developed at the University of Hawaii's Institute for Astronomy.

By combining relatively small mirrors with very large digital cameras we will be able to develop and deploy an economical observing system that will be able to observe the entire available sky several times each month.

The immediate goal of Pan-STARRS is to discover and characterize Earth-approaching objects, both asteroids & comets, which might pose a danger to our planet.

The huge volume of images produced by this system will provide valuable data for many other kinds of scientific programs. Click here for more Information.

A unique facet of Pan-STARRS is its ability to discover transient phenomena in the Universe, including approximately 10,000 new supernovae.

SHOES-Supernovae, HO, for the Equation of State of Dark energy

The present uncertainty in the value of the Hubble constant (resulting in an uncertainty in ΩM) and the paucity of Type Ia supernovae at redshifts exceeding 1 are now the leading obstacles to determining the nature of dark energy. We propose a single, integrated set of observations for Cycle 15 that will provide a 40% improvement in constraints on dark energy. This program will observe known Cepheids in six reliable hosts of Type Ia supernovae with NICMOS, reducing the uncertainty in H_0 by a factor of two because of the smaller dispersion along the instability strip, the diminished extinction, and the weaker metallicity dependence in the infrared. In parallel with ACS, at the same time the NICMOS observations are underway, we will discover and follow a sample of Type Ia supernovae at z > 1.

Together, these measurements, along with prior constraints from WMAP, will provide a great improvement in HST's ability to distinguish between a static, cosmological constant and dynamical dark energy. The Hubble Space Telescope is the only instrument in the world that can make these IR measurements of Cepheids beyond the Local Group, and it is the only telescope in the world that can be used to find and follow supernovae at z > 1. Our program exploits both of these unique capabilities of HST to learn more about one of the greatest mysteries in science.

Recent Research

PANS-Probing Acceleration Now with Supernovae

Type Ia supernovae (SNe Ia) provide the most direct evidence for an accelerating Universe, a result widely attributed to dark energy. Our on-going space-based survey (now called PANS) uses the Hubble Space Telescope to conduct a powerful and straightforward test of the new cosmological model. Observations of SNe Ia at z > 1 are expected to show evidence for a past epoch of cosmic deceleration, a clear signature of a mixed dark-matter and dark-energy Universe.

This survey also provides measurements of the evolution in supernova rates. This allows for alternative measures of the star formation rate history, and give insight on the plausible models for SN Ia progenitor models.

Understanding dark energy may be the biggest current challenge to cosmology and particle physics. To understand the nature of dark energy, we seek to measure its two most fundamental properties: its evolution (i.e., dw/dz), and its recent equation of state (i.e., w(z=0)). SNe Ia at z>1, beyond the reach of the ground but squarely within the reach of HST with ACS, are crucial to break the degeneracy in the measurements of these two basic aspects of dark energy. Here we propose double the precision of dark energy constraints. Should the current best fit model prove to be the correct one, the precision expected from the current proposal will suffice to rule out a cosmological constant at the 99% confidence level. Whatever the result, these objects will provide the basis with which to extend our empirical knowledge of this newly discovered and dominant component of the Universe, and will remain one of the most significant legacies of HST. In addition, our survey and follow-up data will greatly enhance the value of the archival data within the target Treasury fields for galaxy studies.