Suzuki, N., Rubin, D., Lidman, C., Aldering, G., Amanullah, R., Barbary, K., Barrientos, L. F., Botyanszki, J., Brodwin, M., Connolly, N., Dawson, K. S., Dey, A., Doi, M., Donahue, M., Deustua, S., Eisenhardt, P., Ellingson, E., Faccioli, L., Fadeyev, V., Fakhouri, H. K., Fruchter, A. S., Gilbank, D. G., Gladders, M. D., Goldhaber, G., Gonzalez, A. H., Goobar, A., Gude, A., Hattori, T., Hoekstra, H., Hsiao, E., Huang, X., Ihara, Y., Jee, M. J., Johnston, D., Kashikawa, N., Koester, B., Konishi, K., Kowalski, M., Linder, E. V., Lubin, L., Melbourne, J., Meyers, J., Morokuma, T., Munshi, F., Mullis, C., Oda, T., Panagia, N., Perlmutter, S., Postman, M., Pritchard, T., Rhodes, J., Ripoche, P., Rosati, P., Schlegel, D. J., Spadafora, A., Stanford, S. A., Stanishev, V., Stern, D., Strovink, M., Takanashi, N., Tokita, K., Wagner, M., Wang, L., Yasuda, N., Yee, H. K. C. and Project, Supernova Cosmology (2012), "THE HUBBLE SPACE TELESCOPE CLUSTER SUPERNOVA SURVEY. V. IMPROVING THE
DARK- ENERGY CONSTRAINTS ABOVE z > 1 AND BUILDING AN EARLY-TYPE-HOSTED
SUPERNOVA SAMPLE", ASTROPHYSICAL JOURNAL, 746, 1.
Abstract: We present Advanced Camera for Surveys, NICMOS, and Keck
adaptive-optics-assisted photometry of 20 Type Ia supernovae (SNe Ia)
from the Hubble Space Telescope (HST) Cluster Supernova Survey. The SNe
Ia were discovered over the redshift interval 0.623 < z < 1.415. Of
these SNe Ia, 14 pass our strict selection cuts and are used in
combination with the world's sample of SNe Ia to derive the best current
constraints on dark energy. Of our new SNe Ia, 10 are beyond redshift z
= 1, thereby nearly doubling the statistical weight of HST-discovered
SNe Ia beyond this redshift. Our detailed analysis corrects for the
recently identified correlation between SN Ia luminosity and host galaxy
mass and corrects the NICMOS zero point at the count rates appropriate
for very distant SNe Ia. Adding these SNe improves the best combined
constraint on dark-energy density,rho(DE)(z), at redshifts 1.0 < z < 1.6
by 18% (including systematic errors). For a flat. CDM universe, we find
Omega(A) = 0.729 +/- 0.014 (68% confidence level (CL) including
systematic errors). For a flat wCDM model, we measure a constant
dark-energy equation-of-state parameter w = -1.013(-0.073)(+0.068) (68%
CL). Curvature is constrained to similar to 0.7% in the owCDM model and
to similar to 2% in a model in which dark energy is allowed to vary
with parameters w(0) and w(a). Further tightening the constraints on the
time evolution of dark energy will require several improvements,
including high-quality multi-passband photometry of a sample of several
dozenz > 1 SNe Ia. We describe how such a sample could be efficiently
obtained by targeting cluster fields with WFC3 on board HST. The updated
supernova Union2.1 compilation of 580 SNe is available at
http://supernova.lbl.gov/Union.
Keywords: cosmological parameters; distance scale; supernovae: general
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