weighing neutrinos including the largest photometric galaxy survey: megaz dr7
DESCRIPTION
Weighing Neutrinos including the Largest Photometric Galaxy Survey: MegaZ DR7. “A combined constraint on the Neutrinos”. Arxiv: 0911.5291. Shaun Thomas: UCL. Moriond 2010. Outline: Neutrinos have mass! Neutrino signatures in cosmology Probes of the Model Cosmic Microwave Background - PowerPoint PPT PresentationTRANSCRIPT
Weighing Neutrinos including the Largest Photometric Galaxy Survey: MegaZ DR7
Moriond 2010Shaun Thomas: UCL
“A combined constraint on the Neutrinos” Arxiv: 0911.5291
Outline:
1. Neutrinos have mass!
2. Neutrino signatures in cosmology
3. Probes of the Model
• Cosmic Microwave Background
• Galaxy Surveys
• Supernovae and Baryon Oscillations
4. Work: Thomas, Abdalla & Lahav (2009): arXiv:0911.5291 (+ In prep. 2010)
5. For the Future…?
Moriond 2010Shaun Thomas: UCL
Neutrino oscillations indicate they have mass!
But not on the absolute scale of mass…
• Beta-decay kinematics
• Neutrinoless double beta-decay
• Cosmology!
KATRIN
nemo
Thomas, Abdalla, Lahav (2009)
For example…
Not just interesting physics but,an integral part of the cosmological model… Age of precision Cosmology
Moriond 2010Shaun Thomas: UCL
http://www-ik.fzk.de/~katrin/index.html
Signatures in the Model
• Act as radiation or matter and affect the Universe’s expansion history
• Suppress the growth of matter structure and cosmological perturbations
Neutrinos have large thermal velocities and Free-stream out of over-densities/inhomogeneities thus suppressing the clustering of matter and galaxies
Which we might see in a power spectrum…
Moriond 2010Shaun Thomas: UCL
Neutrino fraction is directly related to sum of masses (RHS)
Probes of CosmologyCosmic Microwave Background (CMB)
WMAP 5 year (CMB) : < 1.3 eV (95% CL)Komatsu et al. [arXiv:0803.0547]
Thomas et al. [arXiv:0911.5291]
Model Data Constraint
With the CMB the effect depends on whether neutrinos are relativistic or not:
Moriond 2010Shaun Thomas: UCL
• Suppress potentials - change heights of peaks OR
• Affect matter-radiation balance
Suggestive of a CMB limit ~ 1.5 eV (E.g. Ichikawa 05)
Probes of Cosmology
Supernovae (SN)E.g. Supernova Legacy Survey
CMB + SN + BAO : < 0.69 eV (95% CL)
Baryon Acoustic Oscillations (BAOs)
Standard candle allows one to measure the expansion history
Tighter matter/hubble constraint aids neutrino determination
Standard ruler allows one to measure the expansion history
Tighter matter/hubble constraint aids neutrino determination
Primordial CMB photon-baryon oscillations are imprinted onto late-time matter power spectrum: BAO
Thomas et al. [arXiv:0911.5291]Komatsu et al. [arXiv:0803.0547]
Moriond 2010Shaun Thomas: UCL
E.g. Percival et al
Probes of Cosmology+ Galaxy Clustering! Sloan Digital Sky Survey (SDSS)
• Suppress the growth of matter structure and cosmological perturbations
Smaller Scales
Moriond 2010Shaun Thomas: UCL
Probes of Cosmology+ Galaxy Clustering! Sloan Digital Sky Survey (SDSS)
Thomas, Abdalla & Lahav - in prep
Luminous Red Galaxies (LRGs)
Photometric Redshift
Largest galaxy survey
723,556 LRGs7,746 square degrees
Volume: 3.3 (Gpc /h)^30.45 < z < 0.65
ANNz - Collister and Lahav 2004Padmanabhan et al. 2007
Four redshift bins
Moriond 2010Shaun Thomas: UCL2SLAQ - 13’000 spectroscopic training/evaluation set
Probes of Cosmology+ Galaxy Clustering! Sloan Digital Sky Survey (SDSS)
Including the production of a new SDSS galaxy clustering angular power spectra
Thomas, Abdalla & Lahav - in prep
We can use this with the BAO(!) - Improves combined neutrino constraint further!
One of the largest galaxy surveys to date
Moriond 2010Shaun Thomas: UCL
MegaZ DR7
Probes of Cosmology+ Galaxy Clustering! Sloan Digital Sky Survey (SDSS)
Luminous Red Galaxies (LRGS)4 bins: 0.45 < z < 0.65
CMB + SN + BAO + SDSS LRGs + HST: < 0.28 eV (95% CL)
Thomas et al. [arXiv:0911.5291]
MegaZ DR7
Moriond 2010Shaun Thomas: UCL
12 Parameters:
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Ωbh2;Ωch
2;ΩΛ;τ ;ns;ln(1010As); mυ ;ASZ ;b1;b2;b3;b4∑
Max multipole l=300
Thomas, Abdalla & Lahav [0911.5291]
Cosmology and Neutrinos
Komatsu et al. [arXiv:0803.0547] < 1.3 eV (CMB) < 0.67 eV (CMB+SN+BAO)
Tereno et al. [arXiv:0810.0555] < 0.54 eV (CMB+SN+BAO+WL)
Ichiki, Takada & Takahashi [arXiv:0810.4921] < 0.54 eV (CMB+SN+BAO+WL)
Seljak et al. [arXiv:0604335] < 0.17 eV (+ Lyman Alpha…)
Systematics - e.g. winds?
Using all the aforementioned probes for complementary data constraint Recent BAO data and production of newest galaxy
clustering angular power spectrumCMB+SDSS+SN+BAO+HST
CMB + SN + BAO + SDSS LRGs +HST
With luminous Red Galaxies (LRGs) sampling a large cosmic volume
Cosmology is starting to predict that experiments such as KATRIN (mentioned earlier) will not detect anything
Moriond 2010Shaun Thomas: UCL
0.28 eV
WOOHOO!
Moriond 2010Shaun Thomas: UCL
‘Systematics and Limitations’
Cosmology = Good
However
Parameter DegeneraciesGalaxy Bias Non-linearities
Most quoted results assume cosmological constant cosmology
Degeneracy with w increases error bar
Model underlying matter power spectrum but measure the galaxy power spectrum
Scale dependence…mimic…?
Bias result or lose data
Perturbation theory/ N-body simulations
Although we want tighter neutrino constraints We also want trustworthy neutrino constraints.
Work In Progress…
Moriond 2010Shaun Thomas: UCL
Work for the Future…
E.g. Saito et al 09Brandbyge & Hannestad 09
E.g. Hannestad
L_max = 300 => 0.28 eV
L_max = 200 => 0.34 eV
Summary
• Cosmology is a sensitive neutrino experiment! (Funded billions of years ago!)
• Massive neutrinos suppress the growth of structure
• Probes such as galaxy clustering or weak lensing are sensitive to growth
• Integral part of cosmological model and parameter space
• Have a complete complementary constraint on neutrinos (sub eV region)
• Systematics and limitations still exist though…
• The Future is promising but with work to be done…Tighter neutrino constraint. Trustworthy neutrino constraint.
Having produced data for a tighter constraint
Moriond 2010Shaun Thomas: UCL
Related and Further Reading
Cosmology and Neutrinos
Thomas, Abdalla & Lahav [arXiv:0911.5291]
Komatsu et al. [arXiv:0803.0547]
Tereno et al. [arXiv:0810.0555]
Elgaroy and Lahav [arXiv:0606007]
Seljak et al. [arXiv:0604335]
Brandbyge & Hannestad [arxiv:0812.3149]
Saito et al [arxiv:0907.2922]
Galaxy Clustering
Thomas, Abdalla & Lahav (In Prep. (v. soon))
Neutrino Experiments
NEMO [arXiv:0810.5497]
KATRIN Contact: [email protected]
Moriond 2010Shaun Thomas: UCL
Thank You for Listening!:)
Shaun Thomas: UCL
Simulation - testing the code by reconstructing input cosmologyEvaluated the previous DR4 release which was consistent with Blake et al. (MegaZ DR4)
1,2
1,3
1,4
2,3
Shaun Thomas: UCL
2,4
3,4
Shaun Thomas: UCL
Shaun Thomas: UCL
Mixing matrix profile
Little correlation between multipole bands introduced by partial sky after binning
Shaun Thomas: UCL
Excess Power
€
σ(Cl ) = 2f sky (2l +1) Cl + ΔΩ
N ⎛ ⎝ ⎜
⎞ ⎠ ⎟
€
σ(Cl ) = 2f sky (2l +1) Cl + ΔΩ
N ⎛ ⎝ ⎜
⎞ ⎠ ⎟
€
Cl ,mpsky =
al ,m − NΔΩ( )il ,m
2
Jl ,m
− ΔΩN
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Cl ,mpsky =
al ,m − NΔΩ( )il ,m
2
Jl ,m
− ΔΩN
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il ,m = Yl ,m* dΩ
ΔΩ∫
€
il ,m = Yl ,m* dΩ
ΔΩ∫
€
Jl ,m = Yl ,m2dΩ
ΔΩ∫
€
Cl = Rl ,l 'Cl 'l '∑
€
Cov Cli ,Cl
j( ) = 2fsky (2l +1)
Cli, j( )
2
€
Cov Cli ,Cl
j( ) = 2f sky (2l +1)
Cli, j( )
2
Shaun Thomas: UCL