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Towards a Cosmological Hubble Diagram for Type II-PSupernovae

Description: We present the first high-redshift Hubble diagram for Type II-P supernovae (SNe II-P) based upon five events at redshift upto z {approx}0.3. This diagram was constructed using photometry from the Canada-France-Hawaii Telescope Supernova Legacy Survey and absorption line spectroscopy from the Keck observatory. The method used to measure distances to these supernovae is based on recent work by Hamuy&Pinto (2002) and exploits a correlation between the absolute brightness of SNeII-P and the expansion velocities derived from the minimum of the Fe II 516.9 nm P-Cygni feature observed during the plateau phases. We present three refinements to this method which significantly improve the practicality of measuring the distances of SNe II-P at cosmologically interesting redshifts. These are an extinction correction measurement based on the V-I colors at day 50, across-correlation measurement for the expansion velocity and the ability to extrapolate such velocities accurately over almost the entire plateau phase. We apply this revised method to our dataset of high-redshift SNe II-P and find that the resulting Hubble diagram has a scatter of only 0.26 magnitudes, thus demonstrating the feasibility of measuring the expansion history, with present facilities, using a method independent of that based upon supernovae of Type Ia.
Date: March 20, 2006
Creator: Nugent, Peter; Sullivan, Mark; Ellis, Richard; Gal-Yam, Avishay; Leonard, Douglas C.; Howell, D. Andrew et al.
Partner: UNT Libraries Government Documents Department

GRB 060505: A Possible Short-Duration Gamma-Ray Burst in a Star-Forming Region at a Redshift of 0.09

Description: This article reports the discovery of the GRB optical afterglow and observations of its environment using Gemini South, the Hubble Space Telescope, Chandra, Swift, and the Very Large Array.
Date: March 13, 2007
Creator: Ofek, Efran; Cenko, Brad; Gal-Yam, Avishay; Fox, Derek B.; Nakar, Ehud; Rau, Arne et al.
Partner: UNT College of Arts and Sciences

Binary Microlensing Events from the MACHO Project

Description: This article presents the light curves of 21 gravitational microlensing events from the first six years of the MACHO Project gravitational microlensing survey that are likely examples of lensing by binary systems.
Date: March 27, 2000
Creator: Alcock, C.; Allsman, R. A.; Alves, D.; Axelrod, T. S.; Baines, D.; Becker, A. C. et al.
Partner: UNT College of Arts and Sciences