Title: Distant Type Ia SNe and Cosmology: Constraining the nature of the dark energy and assessing the importance of dust and evolution

Scientific program:


The magnitude-redshift relation of Type Ia supernovae (SNe~Ia) indicates that the universe is dominated by an unknown form of dark energy and that, at the present epoch, the expansion of the universe is accelerating. There are now two important directions to pursue with the SN~Ia cosmology work:
(a) filling in the SN~Ia Hubble diagram to obtain a more complete and detailed expansion history of the universe over the past 10 billion years; and
(b) refining and further testing SNe~Ia as tools for cosmological measurements.

We propose to observe 10 SNe~Ia over the redshift interval z=0.5 to z=1.2 during periods 69 and 71 and to obtain final reference images for an additional 8 SNe~Ia that were discovered in period 67. These observations will dramatically shrink the major-axis of the error ellipse in the Omega-Matter - Omega-Lambda plane, decoupling the measurements of Omega-Matter and Omega-Lambda. Thus, this data set will provide a critical check on the curvature of the universe as inferred from CMB anisotropy measurements. Furthermore, the observations will place constraints on the nature of the ``dark energy'' and, at the same time, assess systematic effects due to grey dust and evolution of SNe~Ia properties.


The observations for period 69 consists of discovering new SNe (programs 169.A-0382(B), (F) and (H)) and re-observing old ones (program 169.A-0382(G)).
Supernovae candidates will be found from a rolling search on the CFHT12k camera on CFHT.
Supernovae candidates will be spectroscopically confirmed with FORS2 - run 169.A-0382(B).
Confirmed supernovae will be imaged with ISAAC - run 169.A-0382(H).
Confirmed supernovae will be imaged with FORS2 - run 169.A-0382(F).

Seventeen type Ia's were discovered last year (see IAU circular 7763). Of these 17, 14 were followed with ground and space based telescopes. We will be using the VLT (run 169.A-0382(G)) to obtain the final reference images. The SNe we will image are:

IAU name z
2001gm - 0.48
2001gn - 1.1
2001go - 0.55
2001gy - 0.511
2001gz - 0.73
2001gq - 0.671
2001hb - 1.05
2001gu - 0.32
2001hd - 0.511
2001gl - 0.36
2001gw - 0.363
2001ha - 0.58
2001he - 0.582
2001hc - 0.35


First CFHT search run - April 11th to 21st.