1 / 13

Dark energy workshop

Dark energy workshop. Copenhagen Aug. 2007. Why the SNLS ?. One of the biggest high-z supernova survey ~500+ supernovae at the end of the survey. + a huge catalogue of galaxies in the lines of sight. Questions to be addressed:

nasya
Download Presentation

Dark energy workshop

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Dark energy workshop Copenhagen Aug. 2007

  2. Why the SNLS ? One of the biggest high-z supernova survey ~500+ supernovae at the end of the survey. + a huge catalogue of galaxies in the lines of sight Questions to be addressed: -Can the intrinsic scatter in the Hubble diagram be further reduced? -Is it possible to detect a correlation between residuals and magnification? -Is it possible to say something about the dark matter distribution of the galaxies?

  3. First estimate (a feasibility check) 700 simulated type Ia Sne using SNLS Sne observations (Astier et al 2006) Magnification of each supernova is estimated using SNOC The SuperNova Observation Calculator Goobar et al (astro-ph/0206409) Most Sne are demagnified and some are significantly magnified small effect Cosmological results and due to lensing ~ 2-3 % Uncertainties due to lensing ~ 1-2% Lensing accounts for 7.5% of the dark energy task force figure of merit

  4. Is it possible to detect a signal ? Expected standard candle brightness (calculated from a cosmological model) Correlation Magnification Plots of residuals vs magnification For estimations of the magnification errors, a work on the GOODs fields has been used (Jonsson et al astro-ph/0612324) Expected linear correlation

  5. Likelihoodratio - (no correlation) (linear correlation) 2 different samples: -with lensing effects -without lensing effects Confidence level of >99%

  6. ANALYSIS OF THE SNLS DATASET

  7. Analysis chain Actual data Galaxy catalogue including magnitudes in the g r i (u) and z -bands + photometric redshift Using the Faber-Jackson relation for ellipticals and the Tully-Fisher relation for spirals we can relate luminosity with mass (for a given model). Galaxy type + B-band absolute magnitude Estimation of the mass of the galaxy using galaxy models like SIS or NFW Estimation of the eta-parameter Using PEGASE : a UV to NIR spectral evolution model of galaxies type absolute magnitudes all sorts of things Estimation of the magnifi-cation of each SNe Using Q-LET, a multiple lens plane algorithm which calculates the magnification with respect to a homogeneous universe

  8. Pegase (a UV to NIR spectral evolution model of galaxies) -Photometric redshift code -Fits redshifted spectral templates templates Absolute B-band magnitudes

  9. The Faber-Jackson/Tully-Fisher relations The Faber-Jackson or Tully-Fisher relations relates the velocity dispersion and the Luminosity of the galaxy. F-J relation (ellipticals) Mitchell et al. (2005) T-F relation (spirals) Bohm et al. (2004) Using a specific model (SIS or NFW) then relates the luminosity to the mass which is finite providing you choose a cut-off radius. Truncation halo: The radius inside which the mean mass density is 200 times the present critical density

  10. smoothness The smoothness parameter All “unobserved” matter is put into a smoothly distributed component. Good test whether the galaxy model is OK Spirals Ellipticals

  11. Another formula relating mass and luminosity Hoekstra et al. (2005) Masse of elliptical galaxies Mean mass Jonsson et al. Hoekstra Jonsson Mean mass Hoekstra et al.

  12. Using the formula of Hoekstra et al. for spirals and ellipticals Using the F-J/T-F relations for the second field

  13. Magnifications

More Related