Program: GN-2006B-Q-10

Title:The Nature of Dark Energy from Type Ia Supernovae
PI:Isobel Hook
Co-I(s): Ray Carlberg, Andy Howell, Don Neill, Kathy Perrett, * Chris Pritchet, Mark Sullivan, Richard McMahon, Justin Bronder, Greg Aldering, * Saul Perlmutter, Reynald Pain

Abstract

Type Ia supernovae (SNe Ia) currently provide the most direct evidence for an accelerating Universe and for the existence of an unknown "dark energy" driving this expansion. The 5-year Supernova Legacy Survey (SNLS) is generating a definitive dataset with well-sampled g'r'i'z' light curves, allowing precise measurement of the cosmological parameters (Omega_Matter, Omega_Lambda). Based on our successful first year results (Astier et al., 2006) we expect the final sample to determine the cosmological equation of state parameter "w" to a precision of +/-0.05 or better, testing theories for the origin of the universal acceleration. The amount of spectroscopic follow-up performed will define the success of this survey. Approximately 550 of the 1000 SNe Ia detected will be spectroscopically confirmed in a coherent program involving all of the world's major telescopes (Gemini, VLT, Keck). Gemini, with nod-and-shuffle observations, plays a pivotal role within this collaboration (Howell et al. 2005). The goal for Gemini this semester is to obtain types and redshifts for ~30 SN Ia candidates with redshifts 0.6-0.9, contributing to a large, high quality and homogeneous SN Ia sample with photometry, spectroscopy, light-curve sampling, and colour information superior to any existing - or planned - sample. This is a continuing QR (quick response) proposal for GMOS-N.

Publications using this program's data