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The High‐Z Supernova Search: Measuring Cosmic Deceleration and Global Curvature of the Universe Using Type Ia Supernovae

B. SchmidtMount Stromlo and Siding Spring Observatories, Private Bag, Weston Creek P.O., ACT 2611, AustraliaN. B. SuntzeffCerro Tololo Inter-American Observatory, Casilla 603, La Serena, Chile; National Optical Astronomy Observatories, operated by the Association of Universities for Research in Astronomy, Inc. (AURA), under cooperative agreement with the National Science FoundationM. M. PhillipsNational Optical Astronomy Observatories, operated by the Association of Universities for Research in Astronomy, Inc. (AURA), under cooperative agreement with the National Science FoundationR. A. SchommerCerro Tololo Inter-American Observatory, Casilla 603, La Serena, Chile; National Optical Astronomy Observatories, operated by the Association of Universities for Research in Astronomy, Inc. (AURA), under cooperative agreement with the National Science FoundationA. ClocchiattiCerro Tololo Inter-American Observatory, Casilla 603, La Serena, Chile; National Optical Astronomy Observatories, operated by the Association of Universities for Research in Astronomy, Inc. (AURA), under cooperative agreement with the National Science FoundationR. KirshnerHarvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138P. GarnavichHarvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138P. ChallisHarvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138B. LeibundgutEuropean Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching, GermanyJ. SpyromilioEuropean Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching, GermanyAdam G. RiessDepartment of Astronomy, University of California, Berkeley, Berkeley, CA 94720-3411A. V. FilippenkoDepartment of Astronomy, University of California, Berkeley, Berkeley, CA 94720-3411M. HamuySteward Observatory, University of Arizona, Tucson, AZ 85721R. Chris SmithDepartment of Astronomy, University of Michigan, 834 Dennison, Ann Arbor, MI 48109-1090Craig J. HoganDepartment of Astronomy, University of Washington, Seattle, WA 98195-1580C. W. StubbsDepartment of Astronomy, University of Washington, Seattle, WA 98195-1580Alan H. DiercksDepartment of Astronomy, University of Washington, Seattle, WA 98195-1580David J. ReissDepartment of Astronomy, University of Washington, Seattle, WA 98195-1580Ron GillilandSpace Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218J. TonryInstitute for Astronomy, University of Hawaii, Manoa, Honolulu, HI 96822J. MazaDepartamento d'Astronomía, Universidad de Chile, Casilla 36-D, Santiago, ChileAlan DresslerCarnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101J. R. WalshEuropean Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching, GermanyRobin CiardulloDepartment of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802

1998en

ABI

Annotatsiya

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 to measure accurate distances with SN Ia. This paper describes the extension of this program to $z \\geq 0.2$, outlining our search techniques and follow-up program. We have devised high-throughput filters which provide accurate two-color restframe $B$ and $V$ light curves of SN Ia, enabling us to produce precise, extinction-corrected luminosity distances in the range $0.25 < z < 0.55$. Sources of systematic error from K-corrections, extinction, selection effects, and evolution are investigated, and their effects estimated. We present photometric and spectral observations of SN 1995K, our program's first supernova, and use the data to obtain a precise measurement of the luminosity distance to the $z=0.479$ host galaxy. This object, when combined with a nearby sample of SN, yields an estimate for the matter density of the Universe of $\\Omega_M = -0.2^{+1.0}_{-0.8}$ if $\\Omega_\\Lambda = 0$. For a spatially flat universe composed of normal matter and a cosmological constant, we find $\\Omega_M = 0.4^{+0.5}_{-0.4}$, $\\Omega_\\Lambda = 0.6^{+0.4}_{-0.5}$. We demonstrate that with a sample of $\\sim 30$ objects, we should be able to determine relative luminosity distances over the range $0 < z< 0.5$ with sufficient precision to measure $\\Omega_M$ with an uncertainty of $\\pm 0.2$.

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DOI: 10.1086/306308

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