7336( 25) - 10/19/98 18:31 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 7336 Version: 25 Check-in Date: 19-Oct-1998 18:27:35 1.Proposal Title: COSMOLOGICAL PARAMETERS Omega AND Lambda FROM HIGH-REDSHIFT TYPE Ia SUPERNOVAE ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 7 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Saul Perlmutter Lawrence Berkeley Laboratory CoI: Reynald Pain IN2P3-CNRS, Paris N CoI: Nino Panagia Space Telescope Science Institute N CoI: Megan Donahue Space Telescope Science Institute N CoI: Richard Ellis Institute of Astronomy, Cambridge N CoI: Andrew Fruchter Space Telescope Science Institute N CoI: Gerson Goldhaber Lawrence Berkeley Laboratory N CoI: Ariel Goobar University of Stockholm N CoI: Don Groom Lawrence Berkeley Laboratory N CoI: Isobel Hook European Southern Observatory N CoI: Alex Kim Lawrence Berkeley Laboratory N CoI: Richard McMahon Institute of Astronomy, Cambridge N CoI: Peter Nugent Lawrence Berkeley Laboratory N ------------------------------------------------------------------------------------ 5. Abstract HST can make a direct measurement of the cosmological parameters, Omega, Lambda, and curvature (Omega_k) using Type Ia supernovae (SNe Ia) as calibrated ``standard candles.'' We propose to follow 12 high-redshift 0.5 < z < 0.9 SNe with HST, to produce a definitive set of high-redshift light curves, begining before maximum light, not obtainable from the ground. The SNe will be selected from a total of \gs 50 SNe Ia discovered on the rising part of their light curves in two search runs at the CTIO-4m, during HST cycle 7 and cycle 7 NICMOS. We will follow eight SNe at z~0.9 with NICMOS in J (F110W) and with WFPC2 in I (F814W) and (at maximum) in R (F675W) and four SNe at z~ 0.5 with WFPC2 in R, and I. We will observe on five dates over the peak of each light curve, and once after the SN has faded. These data will determine the peak magnitude, colors, and decline rate for the 12 light curves. With the high-resolution imaging of NICMOS and WFPC2, the HST is uniquely capable of measuring SN light curves at z~ 0.9 in R, I and J. The final statistical error will be below the narrow dispersion, Sigma < 0.12 mag, of Type Ia SN peak magnitudes (calibrated by decline rate and color), to yield measurements of Omega_M and Omega_Lambda with accuracy as good as Sigma ~ 0.11. ------------------------------------------------------------------------------------ 7336( 25) - 10/19/98 18:31 - [ 2] Observations Description ------------------------ These observations are intended to obtain well-sampled lightcurves with small photometric errors for a sample of Type Ia supernova. The SNe with be discovered the nights of Mar 22 - 31, 1998 at CTIO. The best candidates will be observed at Keck the nights of Mar 29 - 31. We wish HST observations to commence ASAP after candidates have been confirmed at Keck so that we can obtain HST lightcurve points before the SNe have reached maximum light. The lightcurves will be followed past maximum so that their decline rates can be determined for use in correcting for variations in intrinsic peak luminoisity. Real Time Justification ----------------------- none Calibration Justification ------------------------- none Additional Comments ------------------- Target positions are to be refined prior to the deadline for inclusion in Apr 6 schedule. We request that observations be scheduled as early as possible in the Apr 6 queue. ------------------------------------------------------------------------------------