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Why the SNLS ?
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?
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
Most Sne are demagnified and some are significantly magnified
700 simulated type Ia Sne using SNLS Sne observations (Astier et al 2006)
First estimate (a feasibility check)
Magnification of each supernova is estimated using SNOC The SuperNova Observation Calculator Goobar et al (astro-ph/0206409)
Cosmological results
Uncertainties due to lensing ~ 1-2%and due to lensing ~ 2-3 %
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δΩM
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δw
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w = w0 + ′ w (a − a0) Lensing accounts for 7.5% of the dark energy task force figure of merit
Is it possible to detect a signal ?
Expected standard candle brightness(calculated from a cosmological model)
Magnification
Plots of residuals vs magnification
Expected linear correlation
For estimations of the magnificationerrors, a work on the GOODs fieldshas been used (Jonsson et al astro-ph/0612324)
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C =
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χ 2
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χ 2(no correlation) (linear correlation)-
2 different samples: -with lensing effects -without lensing effects
Confidence level of >99%
Likelihood ratio
Using the Faber-Jackson relation for ellipticals and the Tully-Fisher relation for spirals we can relate luminosity with mass (for a given model).
Analysis chain
Actual dataGalaxy catalogue
including magnitudes in the
g r i (u) and z -bands +
photometric redshift
Galaxy type +
B-band absolute
magnitude
Estimation of the mass of the galaxy
using galaxy models like SIS or NFWEstimation of
the eta-parameter
Using PEGASE : a UV to NIR spectral evolution model of galaxies
typeabsolute
magnitudesall sorts of
things
Using Q-LET, a multiple lens plane algorithm which calculates the magnification with respect to a homogeneous universe
Estimation of the
magnifi-cation of
each SNe
-Photometric redshift code
-Fits redshifted spectral templates
Pegase (a UV to NIR spectral evolution model of galaxies)
templates
Absolute B-band magnitudes
The Faber-Jackson or Tully-Fisher relations relates the velocity dispersion and the Luminosity of the galaxy.
Using a specific model (SIS or NFW) then relates the luminosity to the mass which is finite providing you choose a cut-off radius.
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L∝σ β
The Faber-Jackson/Tully-Fisher relations
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log10 σ = −0.091(MB − 4.74 + 0.85z)
F-J relation (ellipticals)Mitchell et al. (2005)
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log10 Vmax = −0.134(MB + 3.61+1.22z)
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σ =Vmax / 2
T-F relation (spirals)Bohm et al. (2004)
Truncation halo:
The radius inside which the mean mass density is 200 times the present critical density
The smoothness parameter
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ηAll “unobserved” matter is put into a smoothly distributed component.
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η(z) =1−ρ g (z)
ρ m (z)
Good test whether the galaxy model is OK
Ellipticals
Spirals
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1.56 ×1012 h−1M⊕
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1.05 ×1011h−1M⊕
Another formula relating mass and luminosity Hoekstra et al. (2005)
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M = 9.9 ⋅1011 LB
1010 h−2LΘ
⎛
⎝ ⎜
⎞
⎠ ⎟
1.5
h−1MΘ
Masse of elliptical galaxies
Jonsson
Hoekstra
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1.56 ×1012 h−1M⊕€
1.55 ×1012 h−1M⊕Mean massJonsson et al.
Mean mass Hoekstra et al.
Using the formula of Hoekstra et al. for spirals and ellipticals
Using the F-J/T-F relations for the second field