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Weighing Neutrinos including the Largest Photometric Galaxy Survey: MegaZ DR7 Moriond 2010Shaun Thomas: UCL “A combined constraint on the Neutrinos” Arxiv:

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Presentation on theme: "Weighing Neutrinos including the Largest Photometric Galaxy Survey: MegaZ DR7 Moriond 2010Shaun Thomas: UCL “A combined constraint on the Neutrinos” Arxiv:"— Presentation transcript:

1 Weighing Neutrinos including the Largest Photometric Galaxy Survey: MegaZ DR7 Moriond 2010Shaun Thomas: UCL “A combined constraint on the Neutrinos” Arxiv:

2 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: (+ In prep. 2010) 5.For the Future…? Moriond 2010Shaun Thomas: UCL

3 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

4 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)

5 Probes of Cosmology Cosmic Microwave Background (CMB) WMAP 5 year (CMB) : < 1.3 eV (95% CL) Komatsu et al. [arXiv: ] Thomas et al. [arXiv: ] ModelDataConstraint 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)

6 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: ] Komatsu et al. [arXiv: ] Moriond 2010Shaun Thomas: UCL E.g. Percival et al

7 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

8 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 LRGs 7,746 square degrees Volume: 3.3 (Gpc /h)^ < z < 0.65 ANNz - Collister and Lahav 2004 Padmanabhan et al Four redshift bins Moriond 2010Shaun Thomas: UCL 2SLAQ - 13’000 spectroscopic training/evaluation set

9 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

10 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: ] MegaZ DR7 Moriond 2010Shaun Thomas: UCL 12 Parameters: Max multipole l=300

11 Thomas, Abdalla & Lahav [ ] Cosmology and Neutrinos Komatsu et al. [arXiv: ] < 1.3 eV (CMB) < 0.67 eV (CMB+SN+BAO) Tereno et al. [arXiv: ] < 0.54 eV (CMB+SN+BAO+WL) Ichiki, Takada & Takahashi [arXiv: ] < 0.54 eV (CMB+SN+BAO+WL) Seljak et al. [arXiv: ] < 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 spectrum CMB+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

12 WOOHOO! Moriond 2010Shaun Thomas: UCL

13 ‘Systematics and Limitations’ Cosmology = Good  However Parameter DegeneraciesGalaxy BiasNon-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 09 Brandbyge & Hannestad 09 E.g. Hannestad L_max = 300 => 0.28 eV L_max = 200 => 0.34 eV

14 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

15 Related and Further Reading Cosmology and Neutrinos Thomas, Abdalla & Lahav [arXiv: ] Komatsu et al. [arXiv: ] Tereno et al. [arXiv: ] Elgaroy and Lahav [arXiv: ] Seljak et al. [arXiv: ] Brandbyge & Hannestad [arxiv: ] Saito et al [arxiv: ] Galaxy Clustering Thomas, Abdalla & Lahav (In Prep. (v. soon)) Neutrino Experiments NEMO [arXiv: ] KATRIN Contact: Moriond 2010Shaun Thomas: UCL Thank You for Listening! :)

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17 Shaun Thomas: UCL Simulation - testing the code by reconstructing input cosmology Evaluated the previous DR4 release which was consistent with Blake et al. (MegaZ DR4)

18 1,2 1,3 1,4 2,3 Shaun Thomas: UCL

19 2,4 3,4 Shaun Thomas: UCL

20 Mixing matrix profile Little correlation between multipole bands introduced by partial sky after binning

21 Shaun Thomas: UCL Excess Power

22 Shaun Thomas: UCL


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