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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
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 2 / 41
A Flavor of LSS
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
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 3 / 41
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)
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 4 / 41
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
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 5 / 41
A Flavor of LSS
The Power Spectrum
M. Tegmark
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 6 / 41
A Flavor of LSS Constraints from the SDSS
SDSS
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 7 / 41
A Flavor of LSS Constraints from the SDSS
The DR7 Power Spectrum
Reid et al, 0907.1659N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 8 / 41
A Flavor of LSS Constraints from the SDSS
The Matter Density
Reid et al, 0907.1659
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 9 / 41
A Flavor of LSS Constraints from the SDSS
Neutrinos
Σmν < 0.63eVReid et al, 0907.1659
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 10 / 41
A Flavor of LSS Constraints from the SDSS
Constraining Inflation
Tegmark et al, 2006
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 11 / 41
Going beyond the standard picture : Two Examples
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
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 12 / 41
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
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 13 / 41
Going beyond the standard picture : Two Examples Dark Energy
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
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 14 / 41
Going beyond the standard picture : Two Examples Dark Energy
BAO - A Standard Ruler
Geometrical probeSound waves in the early Universeimprint a standard rulerLarge scales (∼ 100Mpc/h) minimizeastrophysical systematicsWell understood from analytic andnumerical perspectives
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 15 / 41
Going beyond the standard picture : Two Examples Dark Energy
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
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 16 / 41
Going beyond the standard picture : Two Examples Dark Energy
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.
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 17 / 41
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
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 18 / 41
Going beyond the standard picture : Two Examples Non-Gaussianities
Measurements
Slosar et al, 2008
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 19 / 41
Future Surveys
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
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 20 / 41
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.
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 21 / 41
Future Surveys SDSS-III and BOSS
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
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 22 / 41
Future Surveys SDSS-III and BOSS
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/
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 23 / 41
Future Surveys SDSS-III and BOSS
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)
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 24 / 41
Future Surveys SDSS-III and BOSS
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.
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 25 / 41
Future Surveys SDSS-III and BOSS
Imaging
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 26 / 41
Future Surveys SDSS-III and BOSS
Imaging
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Future Surveys SDSS-III and BOSS
Tiles
Mike Blanton, priv. comm.
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 28 / 41
Future Surveys SDSS-III and BOSS
Dewars
Mike Carr, priv. comm.
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 29 / 41
Future Surveys SDSS-III and BOSS
Grisms
Robert Barkhouser, priv. comm.
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 30 / 41
Future Surveys SDSS-III and BOSS
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.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
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 31 / 41
Future Surveys SDSS-III and BOSS
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.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
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 31 / 41
Future Surveys SDSS-III and BOSS
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.....
N. Padmanabhan (Yale) Cosmology with LSS 07-14-2009 32 / 41
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
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Future Surveys BigBOSS
Distance measures
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Future Surveys BigBOSS
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
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Future Surveys BigBOSS
Comparing surveys - Modes
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Future Surveys BigBOSS
Comparing surveys - Growth
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Future Surveys BigBOSS
Cosmological constraints
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Future Surveys BigBOSS
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)
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Future Surveys BigBOSS
Timescales
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Future Surveys BigBOSS
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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