Constraining Cosmology with LSS surveys · I SNe, BAO. The Inhomegeneous Universe I Growth of...

Constraining Cosmology with LSS surveys

Nikhil Padmanabhan1

1Yale University

07-14-2009 / TeVPA ’09

N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 1 / 41

Outline

1 A Flavor of LSSConstraints from the SDSS

2 Going beyond the standard picture : Two ExamplesDark EnergyNon-Gaussianities

3 Future SurveysSDSS-III and BOSSBigBOSS


A Flavor of LSS

Outline





A Flavor of LSS

Some Comments

Mapping the distribution of matterProbes the initial conditions of the Universe. . .. . . and its subsequent evolution2D maps - imaging surveys (eg. PanSTARRS, SkyMapper, DES,LSST)2D maps - gravitational lensing3D maps - redshift surveys (eg. 2dF, SDSS)


A Flavor of LSS

Mapping the Universe

Age of Surveys

Cover wide range of redshifts,wavelengths

SDSS, 2dF, 2MASS, DEEP2, . . .

Pan-STARRS,SDSS-III, WiggleZ,HETDEX, LSST, JDEM, BigBOSS,. . .

Very rich data sets

M. Tegmark


A Flavor of LSS

The Power Spectrum

M. Tegmark


A Flavor of LSS Constraints from the SDSS

SDSS



The DR7 Power Spectrum

Reid et al, 0907.1659N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 8 / 41


The Matter Density

Reid et al, 0907.1659



Neutrinos

Σmν < 0.63eVReid et al, 0907.1659



Constraining Inflation

Tegmark et al, 2006


Going beyond the standard picture : Two Examples

Outline





Going beyond the standard picture : Two Examples Dark Energy

A Balanced Budget?An accelerating Universe

Discovery by using SNe asstandard candles

Now verified by multiple sources

75% of the energy budget

Only just starting to probe its nature

www.lsst.org



Two Dichotomies

G or T?I Change the matter content of the Universe, new fieldI Modify gravity

The Homogeneous UniverseI Standard rulers/candles.I Geometrical probesI Does not distinguish G vs TI SNe, BAO.

The Inhomegeneous UniverseI Growth of fluctuationsI Distinguish modified gravity from dark energyI Lensing, redshift space distortions



BAO - A Standard Ruler

Geometrical probeSound waves in the early Universeimprint a standard rulerLarge scales (∼ 100Mpc/h) minimizeastrophysical systematicsWell understood from analytic andnumerical perspectives



First Detections

Need to survey very large volumes. Ruler is100 Mpc/h, and is statistical, so needmultiple independent volumes.

First survey to reach necessary volume :the SDSS Luminous Red Galaxy Surveyand 2dF Galaxy Surveys

First detection by Eisenstein et al (SDSS)and Cole et al (2dF)

D(0.35) to ∼ 3%

Detection using SDSS photometric surveyz < 0.6 (NP et al, 2007)

Detection of both transverse and radialterms (Gaztanaga et al, 2008)

Final DR7 results - Percival et al, 2009

Eisenstein et al, 2005



Probing growth

Redshift space distortions

Velocity field sensitive to matter distribution.

Velocity field distorts the galaxy correlationfunction; makes it anisotropic – redshiftspace distortions.

Measuring z-space distortions allowmeasurement of growth of structure.

Independent probe of growth (i.e. not weaklensing); tests a different aspect of structureformation.


Going beyond the standard picture : Two Examples Non-Gaussianities

Non-Gaussianities

Initial conditions assumed to beGaussian in standard pictureTests of models of inflationφ ∼ φ+ fNLφ

2

Expect deviations fNL ∼ 1Nongaussianities affect clustering ofbiased objects on large scalesNot degenerate with galaxy formation Dalal et al, 2008


Going beyond the standard picture : Two Examples Non-Gaussianities

Measurements

Slosar et al, 2008


Future Surveys

Outline





Future Surveys SDSS-III and BOSS

BOSS : A next generation BAO experiment

How to do a precisionz < 1 BAO expt.?

After SDSS, then what?

Percival et al, 2006

SDSS imaging detects redgalaxies to z ∼ 0.8(2SLAQ, AGES)

The SDSS spectrographstill is one of the best widefield MOS.



BOSS in overview

Ω = 10,000 deg2

Fill in SDSS stripes in the south; 8500deg2 in North, 3000deg2 in South

Galaxies : z ∼ 0.1− 0.7

QSOs (Lyman-α forest) : z ∼ 2.3− 3.3

1% dA, 2% H at z ∼ 0.35, 0.6

1.5% dA, H at z ∼ 2.5

Leverage existing hardware/software where possible



BOSS : A brief historyJuly 2006 Competitive proposal to use (upgraded) SDSS

telescope for next-generation BAO experimentNov 2006 BOSS proposal selected (from 7) for all

dark+grey time for 5 of 6 yearsNov 2006 First BOSS collaboration meeting (NYU)Feb 2007 DOE R&D proposal for upgrading SDSS

spectroscopic systemOct 2007 Approval from Sloan foundation

2007 Funding proposals in to NSF and DOE2008 Approval from NSF; R&D funding from DOE

July 15, 2008 SDSS-III beginsSept 2008 BOSS imaging begins

Fall 2009-2014 BOSS spectroscopic survey at APO

http://www.sdss3.org/



BOSS : As part of SDSS-3SEGUE-2 : Kinematic and chemical structure from 350,000 starsin the outer Galaxy.APOGEE : High resolution IR spectroscopy of stars in the Galacticbulge, bar and disk.MARVELS : Radial velocity planet search around 11,000 starsBOSS : BAO with 1.5 million LRGs (z < 0.7) and 160,000 QSOs(2.3 < z < 3.3)



What’s next for BOSS?

July 15, 2008: SDSS-II ended, SDSS-III began.Completed ∼ 3000 deg2 on imaging in the South in Fall 2008.



Imaging



Imaging



Tiles

Mike Blanton, priv. comm.



Dewars

Mike Carr, priv. comm.



Grisms

Robert Barkhouser, priv. comm.




July 15, 2008: SDSS-II ended, SDSS-III began.Completed ∼ 3000 deg2 on imaging in the South in Fall 2008.Upgrade spectrographs Summer 09.Commissioning on Stripe 82, Fall 2009LRG/QSO spectroscopy Fall 2009 - 2014At which point, we should know....

I wp = −??.??± 0.03, wa =??.??± 0.28I h = 0.??± 0.008, ΩK = 0.??± 0.002




July 15, 2008: SDSS-II ended, SDSS-III began.Completed ∼ 3000 deg2 on imaging in the South in Fall 2008.Upgrade spectrographs Summer 09.Commissioning on Stripe 82, Fall 2009LRG/QSO spectroscopy Fall 2009 - 2014At which point, we should know....

I wp = −??.??± 0.03, wa =??.??± 0.28I h = 0.??± 0.008, ΩK = 0.??± 0.002



More Cosmology

Precision measurements of H0 (1%), ΩK (0.2%)Constrains D(2)/D(1000) and D(0.5)/D(1000) to 0.6% and 1%within ΛCDM

Improved large scale structure constraints (250,000 modes withk < 0.2)Improved measurements from the Lyman-α forestImproved measurements of neutrino massesA S/N=200 measurement of ξgm from galaxy-galaxy lensing, directprobe of D(z)

Constrain fnl <∼ 10.....


Future Surveys BigBOSS

Beyond BOSS - BigBOSS

BigBOSS: The Ground-Based Stage IV BAO Experiment

BBiiggBBOOSSSS TThhee GGrroouunndd--BBaasseedd SSttaaggee--IIVV BBAAOO EExxppeerriimmeenntt

SSuubbmmiitttteedd bbyy LLBBNNLL aanndd NNOOAAOO

New 4000 fiber spectrograph forMayall 4m at KPNO

14,000 sq.deg., 0 < z < 2

Possibility of continuation usingCTIO 4m

DE constraints competitive withJDEM

Complementary to planned imagingsurveys

arXiv:0904.0468



Distance measures



Comparing surveys - Modes

Linear modes = cosmological informationknl(z = 0) ∼ 0.1h/Mpc; scale with growthBOSS = 4× 105

BigBOSS LRGs = 2× 106

BigBOSS ELG = 1.5× 107



Comparing surveys - Modes



Comparing surveys - Growth



Cosmological constraints



Primordial non-gaussianities

Scale dependent bias on largescales!

Volume matters!

fNL = 1 interesting region

Dashed line is fNL = 5

Compare multiple samples(suppress sample variance)



Timescales



Conclusions

Age of surveysNext generation of surveys will map a large fraction of the UniverseMultiple points of contact with particle physicsRe-examine “standard” cosmological observations within thecontext of particle physics extensionsRich data sets, stay tuned!


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Constraining Cosmology with LSS surveys · I SNe, BAO. The Inhomegeneous Universe I Growth of...

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