THE CARNEGIE SUPERNOVA PROJECT: FIRST NEAR-INFRARED HUBBLE DIAGRAM TO z approx 0.7

Journal Article · Tue Oct 20 00:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/704/2/1036· OSTI ID:21367360

Freedman, Wendy L; Burns, Christopher R; Wyatt, Pamela; Persson, S E; Madore, Barry F; Kelson, Daniel D; Murphy, D C; Sturch, Laura ^[1]; Phillips, M M; Contreras, Carlos; Folatelli, Gaston; Gonzalez, E Sergio; Morrell, Nidia; Roth, Miguel; Stritzinger, Maximilian ^[2]; Hamuy, Mario ^[3]; Hsiao, Eric ^[4]; Suntzeff, Nick B ^[5]; Astier, P; Balland, C ^[6]

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1. Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
2. Carnegie Institution of Washington, Las Campanas Observatory, Colina El Pino, Casilla 601 (Chile)
3. Universidad de Chile, Departmento de Astronomia, Casilla 36-D, Santiago (Chile)
4. Department of Physics and Astronomy, University of Victoria, P.O. Box 3055, Stn CSC, Victoria, BC V8W 3P6 (Canada)
5. Physics Department, Texas A and M University, College Station, TX 77843 (United States)
6. LPNHE, CNRS-IN2P3 and Universites Paris VI and VII, 4 place Jussieu, 75252 Paris Cedex 05 (France)

The Carnegie Supernova Project (CSP) is designed to measure the luminosity distance for Type Ia supernovae (SNe Ia) as a function of redshift, and to set observational constraints on the dark energy contribution to the total energy content of the universe. The CSP differs from other projects to date in its goal of providing an I-band rest-frame Hubble diagram. Here, we present the first results from near-infrared observations obtained using the Magellan Baade telescope for SNe Ia with 0.1 <z < 0.7. We combine these results with those from the low-redshift CSP at z < 0.1. In this paper, we describe the overall goals of this long-term program, the observing strategy, data reduction procedures, and treatment of systematic uncertainties. We present light curves and an I-band Hubble diagram for this first sample of 35 SNe Ia, and we compare these data to 21 new SNe Ia at low redshift. These data support the conclusion that the expansion of the universe is accelerating. When combined with independent results from baryon acoustic oscillations, these data yield OMEGA {sub m} = 0.27 +- 0.02(statistical) and OMEGA{sub DE} = 0.76 +- 0.13(statistical) +- 0.09(systematic), for the matter and dark energy densities, respectively. If we parameterize the data in terms of an equation of state, w (with no time dependence), assume a flat geometry, and combine with baryon acoustic oscillations, we find that w = -1.05 +- 0.13(statistical) +- 0.09(systematic). The largest source of systematic uncertainty on w arises from uncertainties in the photometric calibration, signaling the importance of securing more accurate photometric calibrations for future supernova cosmology programs. Finally, we conclude that either the dust affecting the luminosities of SNe Ia has a different extinction law (R{sub V} = 1.8) than that in the Milky Way (where R{sub V} = 3.1), or that there is an additional intrinsic color term with luminosity for SNe Ia, independent of the decline rate. Understanding and disentangling these effects is critical for minimizing the systematic uncertainties in future SN Ia cosmology studies.

• OSTI ID: 21367360
• Journal Information: Astrophysical Journal, Vol. 704, Issue 2; Other Information: DOI: 10.1088/0004-637X/704/2/1036; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
CALIBRATION
COLOR
COSMOLOGY
DUSTS
EQUATIONS OF STATE
LUMINOSITY
MILKY WAY
NONLUMINOUS MATTER
OSCILLATIONS
RED SHIFT
SUPERNOVAE
TELESCOPES
TIME DEPENDENCE
UNIVERSE
VISIBLE RADIATION
BINARY STARS
ELECTROMAGNETIC RADIATION
EQUATIONS
ERUPTIVE VARIABLE STARS
GALAXIES
MATTER
OPTICAL PROPERTIES
ORGANOLEPTIC PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
STARS
VARIABLE STARS