@article {27990,
	title = {New Hubble Space Telescope Discoveries of Type Ia Supernovae at z >= 1: Narrowing Constraints on the Early Behavior of Dark Energy},
	journal = {The Astrophysical Journal},
	volume = {659},
	year = {2007},
	note = {n/a},
	month = {April 1, 2007},
	pages = {98-121},
	abstract = {We have discovered 21 new Type Ia supernovae (SNe Ia) with the HubbleSpace Telescope (HST) and have used them to trace the history of cosmicexpansion over the last 10 billion yr. These objects, which include 13spectroscopically confirmed SNe Ia at z\&gt;=1, were discovered during 14epochs of reimaging of the GOODS fields North and South over 2 yr withthe Advanced Camera for Surveys on  HST. Together with a recalibrationof our previous HST-discovered SNe Ia, the full sample of 23 SNe Ia atz\&gt;=1 provides the highest redshift sample known. Combining these datawith previous SN Ia data sets, we measured H(z) at discrete,
},
	url = {http://adsabs.harvard.edu/abs/2007ApJ...659...98R},
	author = {Riess, Adam G. and Strolger, Louis-Gregory and Casertano, Stefano and Ferguson, Henry C. and Mobasher, Bahram and Gold, Ben and Challis, Peter J. and Filippenko, Alexei V. and Jha, Saurabh and Li, Weidong and Tonry, John and Foley, Ryan and Kirshner, Robert P. and Dickinson, Mark and MacDonald, Emily and Eisenstein, Daniel and Livio, Mario and Younger, Josh and Xu, Chun and Dahl{\'e}n, Tomas and Stern, Daniel}
}
