Статья

Supernova Limits on the Cosmic Equation of State

P. GarnavichHarvard?Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138Saurabh W. JhaHarvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138Peter ChallisHarvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138A. ClocchiattiDepartmento de Astronomía y Astrophisica, Pontificia Universidad Católica, Casilla 104, Santiago 22, ChileAlan H. DiercksDepartment of Astronomy, University of Washington, Seattle, WA 98195A. V. FilippenkoDepartment of Astronomy, University of California, Berkeley, CA 94720-3411Ron GillilandSpace Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218Craig J. HoganDepartment of Astronomy, University of Washington, Seattle, WA 98195R. KirshnerHarvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138B. LeibundgutEuropean Southern Observatory, Karl-Schwarzschild-Strasse 2, Garching, GermanyM. M. PhillipsCerro Tololo Inter-American Observatory, Casilla 603, La Serena, ChileDavid J. ReissDepartment of Astronomy, University of Washington, Seattle, WA 98195Adam G. RiessDepartment of Astronomy, University of California, Berkeley, CA 94720-3411B. SchmidtMount Stromlo and Siding Spring Observatory, Private Bag, Weston Creek P.O., AustraliaR. A. SchommerCerro Tololo Inter-American Observatory, Casilla 603, La Serena, ChileR. Chris SmithUniversity of Michigan, Department of Astronomy, 834 Dennison, Ann Arbor, MI 48109J. SpyromilioEuropean Southern Observatory, Karl-Schwarzschild-Strasse 2, Garching, GermanyC. W. StubbsDepartment of Astronomy, University of Washington, Seattle, WA 98195N. B. SuntzeffCerro Tololo Inter-American Observatory, Casilla 603, La Serena, ChileJ. TonryInstitute for Astronomy, University of Hawaii, Manoa, HI 96822Sean M. CarrollInstitute for Theoretical Physics, University of California, Santa Barbara, CA 93106

1998en

ABI

Аннотация

We use Type Ia supernovae studied by the High-z Supernova Search Team to constrain the properties of an energy component that may have contributed to accelerating the cosmic expansion. We find that for a flat geometry the equation-of-state parameter for the unknown component, αx = Px/ρx, must be less than -0.55 (95% confidence) for any value of Ωm, and it is further limited to αx < -0.60 (95% confidence) if Ωm is assumed to be greater than 0.1. These values are inconsistent with the unknown component being topological defects such as domain walls, strings, or textures. The supernova (SN) data are consistent with a cosmological constant (αx = -1) or a scalar field that has had, on average, an equation-of-state parameter similar to the cosmological constant value of -1 over the redshift range of z ~ 1 to the present. SN and cosmic microwave background observations give complementary constraints on the densities of matter and the unknown component. If only matter and vacuum energy are considered, then the current combined data sets provide direct evidence for a spatially flat universe with Ωtot = Ωm + ΩΛ = 0.94 +/- 0.26 (1 σ).

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Идентификаторы

DOI: 10.1086/306495

Цитирования и источники

Цитирований: 4Использованных источников: 0

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