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

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

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

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

5. Edvard Mörtsell, Stockholm University 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

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

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

8. Edvard Mörtsell, Stockholm University 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

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

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

11. Edvard Mörtsell, Stockholm University 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 %

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

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

14. Edvard Mörtsell, Stockholm University 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

15. Edvard Mörtsell, Stockholm University 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

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

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

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…