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Lensing of supernovae by galaxies and galaxy clusters

Lensing of supernovae by galaxies and galaxy clusters. Edvard Mörtsell, Stockholm Jakob Jönsson, Oxford Ariel Goobar; Teresa Riehm, Stockholm. Outline. Lensing of supernovae by galaxies Lensing of supernovae by galaxy clusters. Supernova cosmology. Davis, EM et al (2007).

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Lensing of supernovae by galaxies and galaxy clusters

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  1. Lensing of supernovae by galaxies and galaxy clusters Edvard Mörtsell, Stockholm Jakob Jönsson, Oxford Ariel Goobar; Teresa Riehm, Stockholm

  2. Outline • Lensing of supernovae by galaxies • Lensing of supernovae by galaxy clusters Edvard Mörtsell, Stockholm University

  3. Supernova cosmology Davis, EM et al (2007) SN = Type Ia supernova = SN Ia Edvard Mörtsell, Stockholm University

  4. Davis, EM et al (2007) Distance modulus = m – m(empty universe) Edvard Mörtsell, Stockholm University

  5. Magnitude uncertainties • Evolution (0.15 mag) • Intrinsic dispersion (0.15 mag): Gaussian • Dust (0.15 mag): Increases with redshift • Gravitational lensing (0.15 mag) • Increases with redshift • Averages out • Can be corrected for • We need to get down to 0.015 mag Edvard Mörtsell, Stockholm University

  6. Credit: Riess, STScI Relate dark matter to luminous matter: Estimated magnification: 0.15 mag Correcting for lensing SN 1997ff: The most distant Type Ia supernova at z = 1.755 Edvard Mörtsell, Stockholm University

  7. Riess et al (2001) Edvard Mörtsell, Stockholm University

  8. Uncertainties in lensing estimates • Magnitude limit • Finite field size • Redshift and position uncertainties • Luminous matter to dark matter: • Faber-Jackson and Tully-Fisher relations • Dark matter halo profile and extent Luminous matter Edvard Mörtsell, Stockholm University

  9. More supernovae in GOODS fields Jönsson et al (2006) Edvard Mörtsell, Stockholm University

  10. Tentative detection (90 % CL) of correlation Lensing vs Hubble residuals Jönsson et al (2006) Edvard Mörtsell, Stockholm University

  11. Impact on cosmological fits • Corrections can decrease the scatter from gravitational lensing by a factor of a few • The bias introduced is negligible [Jönsson et al (2008)] • Cosmological constraints from supernovae can be improved by 5-10 % Edvard Mörtsell, Stockholm University

  12. Davis, EM et al (2007) Edvard Mörtsell, Stockholm University

  13. The slope can be used to estimate masses with 50 % accuracy using 450 SN Ia (SNLS) Supernovae and halo masses Correct masses (circles) Underestimated masses (squares) Overestimated masses (triangles) Edvard Mörtsell, Stockholm University

  14. Supernovae and galaxy clusters • Clusters as telescopes • Explore supernova rates at high redshifts • Increase leverage of Hubble diagram • Possibility to measure time delay and absolute magnification Edvard Mörtsell, Stockholm University

  15. Pilot study • Near-IR observations ISAAC/VLT (PI: Ariel Goobar) • SZ and J-band matching archival data • A1689, A1835, AC114 monitored in spring of 2007 • Magnitude limit SZ < 24 mag (Vega) • Average magnification in ISAAC field: • A1689: -3 mag • A1835: -1,5 mag • AC114: -1 mag Edvard Mörtsell, Stockholm University

  16. Goobar et al (2008) Edvard Mörtsell, Stockholm University

  17. Type IIp at z = 0.68 magnified > 2 mag !!!Preliminary!!! A transient candidate A1689 archival ISAAC and FORS2 data Goobar et al (2008) Edvard Mörtsell, Stockholm University

  18. Edvard Mörtsell, Stockholm University

  19. Summary and outlook • Galaxy lenses harmless for SN Ia cosmology • SN Ia potentially useful as probes of halo masses • A successful pilot study looking for supernovae behind cluster telescopes • Further observation using HAWK-I camera will help constraining supernova rates, dark matter distribution, Hubble constant, dark energy properties… Edvard Mörtsell, Stockholm University

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