Nicholas B . Suntzeff

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We present constraints on the dark energy equation-of-state parameter, w = P/(ρc), using 60 Type Ia supernovae (SNe Ia) from the ESSENCE supernova survey. We derive a set of constraints on the nature of the dark energy assuming a flat Universe. By including constraints on (ΩM, w) from baryon acoustic oscillations, we obtain a value for a static(More)
We present a new compilation of Type Ia supernovae (SNe Ia), a new data set of low-redshift nearby-Hubble-flow SNe, and new analysis procedures to workwith these heterogeneous compilations. This ‘‘Union’’ compilation of 414 SNe Ia, which reduces to 307 SNe after selection cuts, includes the recent large samples of SNe Ia from the Supernova Legacy Survey and(More)
The High-z Supernova Search Team has discovered and observed 8 new supernovae in the redshift interval z = 0.3–1.2. These independent observations, analyzed by similar but distinct methods, confirm the result of Riess et al. (1998a) and Perlmutter et al. (1999) that supernova luminosity distances imply an accelerating universe. More importantly, they extend(More)
We examine the absolute luminosities of 29 SNe Ia in the Calán/Tololo survey. We confirm a relation between the peak luminosity of the SNe and the decline rate as measured by the light curve, as suggested by Phillips (1993). We derive linear slopes to this magnitude-decline rate relation in BV(I)KC colors, using a sample with BMAX-VMAX < 0.2. The scatter(More)
The High-Z Supernova Search is an international collaboration to discover and monitor type Ia supernovae (SN Ia) at z > 0.2 with the aim of measuring cosmic deceleration and global curvature. Our collaboration has pursued a basic understanding of supernovae in the nearby Universe, discovering and observing a large sample of objects, and developing methods(More)
We develop a method for estimating the host galaxy dust extinction for type Ia supernovae based on an observational coincidence first noted by Lira (1995), who found that the B − V evolution during the period from 30–90 days after V maximum is remarkably similar for all events, regardless of light curve shape. This fact is used to calibrate the dependence(More)
We report optical and infrared spectroscopic observations of the Type Ia SN 1999ee and the Type Ib/c SN 1999ex, both of which were hosted by the galaxy IC 5179. For SN 1999ee we obtained a continuous sequence with an unprecedented wavelength and temporal coverage beginning 9 days before maximum light and extending through day 42. Before maximum light SN(More)
We formulate a new, revised and coherent understanding of the structure and dynamics of the Large Magellanic Cloud (LMC), and its orbit around and interaction with the Milky Way. Much of our understanding of these issues hinges on studies of the LMC line-of-sight kinematics. The observed velocity field includes contributions from the LMC rotation curve V(More)
We present optical (UBVRI) sky brightness measures from 1992 through 2006. The data are based on CCD imagery obtained with the CTIO 0.9-m, 1.3-m, and 1.5-m telescopes. The Band V -band data are in reasonable agreement with measurements previously made at Mauna Kea, though on the basis of a small number of images per year there are discrepancies for the(More)
We present BVRI photometry of the Type Ia supernovae 1999da, 1999dk, 1999gp, 2000bk, and 2000ce, plus infrared photometry of three of these. These objects exhibit the full range of decline rates of Type Ia supernovae. Combined optical and infrared data show that families of V − infrared color curves can be used to derive the host extinction (AV ) of these(More)