Connecting fundamental physics with observations, KITPC, Observational windows of cosmological physics 张鹏杰 （ Zhang, Pengjie) 中国科学院上海天文台 Shanghai Astronomical Observatory Chinese Academy of Science

Connecting fundamental physics with observations, KITPC, The dark universe The visible world The dark universe Dark matter? Dark energy? Modified gravity? Violation of EP, Lorentz invariance? Violation of Corpernican Principle?

Connecting fundamental physics with observations, KITPC, Windows to the dark universe 21cm Soon to detect

Connecting fundamental physics with observations, KITPC, General relativity and GR tests General principle of relativity Equivalence principle Field equation Confirmed at 10^(-13) General covarianceTensor analysis perihelion shift light deflection time dilation/frequency shift orbital decay (gravitational wave) time delay geodetic effect ?frame dragging effect (e.g.

Connecting fundamental physics with observations, KITPC, GR and cosmology: dark matter Density fluctuations in baryons are ~10^-5 at ~100 Mpc/h at z~1100 Density fluctuations today are ~0.1 at 100 Mpc/h If only baryons and photons exist, density fluctuations today <10^-2. Even worse at smaller scales So dark matter must exist, whose rms fluctuation must be orders of magnitude larger than that in baryons at CMB epoch! X

Connecting fundamental physics with observations, KITPC, GR and modern cosmology: non-zero cosmological constant Cosmic acceleration – D L -z relation from cosmic standard candles SNe Ia, Decay of gravitational potential (the Integrated Sachs-Wolfe effect) Riess et al. 2005

Connecting fundamental physics with observations, KITPC, The story of the Vulcan planet Newtonian gravity predicts the Mercury orbit to be closed (if Sun+Mercury only) Observations found that the Mercury orbit is not closed and the perihelion procession is 43 arcsec/century Theory conflicts with observation→New mass? Flaw in Newtonian gravity? Le Verrier (the one predicted Neptune) postulated the planet Vulcan We now know Vulcan does not exist and instead, Newtonian gravity goes wrong

Connecting fundamental physics with observations, KITPC, Modifications in particle physics Modifications in general relativity Theories beyond the GR (with non-zero cc) +DM LCDM cosmology Dark matter WIMP Axion etc MG replacing DM MOND (TeVeS) etc Unified DM/DE DM/DE interaction Unified MG Dark energy Quintessence Phantom Quintom etc MG replacing DE DGP f(R) etc Cosmological consequences ExpansionWell understoodPartly understood Linear perturbationAlmost well understoodPartly understood Nonlinear evolution (simulations and/or semi-analytical cal.) Almost well understood for smooth DE Preliminary for clustered DE Big progress, but still preliminary

Connecting fundamental physics with observations, KITPC, To describe the universe Zero order (The overall expansion and geometry) First order (The large scale structure) for dark energy Modified gravity example: H in flat CDM and DGP

Connecting fundamental physics with observations, KITPC, Probes of the expansion Type Ia supernovae (standard candles) Baryon acoustic oscillation in LSS and CMB (standard ruler) Fundamental plane, Faber-Jackson & Tully-Fisher of galaxies Age (globular clusters, galaxy age-z..) Gravitational lensing time delay SZ-X ray cluster fluxes Cluster gas fraction Gamma ray bursts Alcock-Paczynski (AP) test.....

Connecting fundamental physics with observations, KITPC, Expansion rate to test gravity Song et al reminder: H in flat CDM and DGP DPG is disfavored comparing to LCDM Stage IV: SNAP, LSST, etc. thousands well calibrated SNe Ia sub-1% accuracy in D L

Connecting fundamental physics with observations, KITPC, Baryon acoustic oscillations as cosmological standard rulers Eisenstein, et al astro-ph/ tell us the distance and H(z)

Connecting fundamental physics with observations, KITPC, BAO: clean physics measures both D(z) and H(z) Stage IV projects: SKA, ADEPT, HSHS,etc. Can reach sub-1% accuracy Blake et al. 2006

Connecting fundamental physics with observations, KITPC, Some near and far future probes Near future –Water maser orbital motion measurement Far future –Gravitational wave of black hole binaries –Sandage-Loeb test (temporal shift in Lyman- alpha absorption lines)

Connecting fundamental physics with observations, KITPC, Water maser: a semi-absolute distance indicator Barvainis & Antonucci, astro-ph/ water maser Observing these water maser cloud for years to measure the proper motion and acceleration

Connecting fundamental physics with observations, KITPC, Water maser: a semi-absolute distance indicator astro-ph/

Connecting fundamental physics with observations, KITPC, Sandage-Loeb test Observe the lines for decades and measure motion against time A measure on H observables A. Sandage, Astrophys. J. 139, 319 (1962). A. Loeb, Astrophys. J. 499, L111 (1998), [astro- ph/ ]. Lyman-alpha absorption (Lyman-alpha forest)

Connecting fundamental physics with observations, KITPC, Corasaniti et al.,arXiv:astro-ph/ v1 Unique tool to measure H(z) at z~3

Connecting fundamental physics with observations, KITPC, Standard Sirens: gravitational waves from SMBBH and short GRB (e.g. Hughes & Holz, 2003; Dalal et al. 2006) Gravitational wave of binaries can be used for self-calibrated precision distance measurement (Challenge: position?) Short GRB: can be well localized Low z GRB will fix H 0 High z SMBBH: measure w GRB b The first short GRB been located SMBBH detected by Chandra

Connecting fundamental physics with observations, KITPC, Hughes and Holzastro-ph/ Dalal et al. astro-ph/ SMBBH Solar mass BBH

Connecting fundamental physics with observations, KITPC, CMB: D SN: D BAO: D,H 21cm BAO: D, H maser: D GW: DGW SMBBH: D SL: H redshift expansion probes cluster: fgas, SZ/X-ray: D weak lensing: D GRB: D

Connecting fundamental physics with observations, KITPC, Probes of the large scale structure They may not probe what we think that they probe!! gravitational potentials –Gravitational lensing –Galaxy/cluster peculiar velocities –The integrated Sachs-Wolfe effect density –galaxy clustering –cluster abundance fluid velocity –The kinetic Sunyaev Zel'dovich effect? Refer to Jain & ZPJ, 2008, PRD for details ? ?

Connecting fundamental physics with observations, KITPC, Gravitational lensing Distortion in galaxy shape （ cosmic shear) Sophisticated method Change in galaxy number density （ cosmic magnification) Detected Anisotropies and non- Gaussianity in cosmic backgrounds (CMB, 21cm, etc.) Preliminary detection in WMAP

Connecting fundamental physics with observations, KITPC, How to do precision lensing measurement Cosmic shear (by far the most sophiscated) –Even with galaxy disk orientation measurement! ( Morales, 2007 arXiv:astro- ph/ ) Lensing of cosmic backgrounds –CMB lensing Seljak & Zaldarriaga, Zaldarriaga & Seljak 1998;Hu & Oakamoto 2002 –21 cm background lensing Cooray 2004; Pen 2004; Zahn & Zaldarriaga 2006; Mandel & Zaldarriaga 2006; But non-Gaussianity! Lensing magnification in flux – Ia supernovae Cooray et al. 2006; Dodelson & Vallinotto 2006; but see ZPJ & Corasaniti 2007 –Galaxy fundamental plane Bertin & Lombard 2006; but see ZPJ & Corasaniti 2007 Cosmic magnification (lensing induced galaxy density fluctuations) –Magnification-galaxy ( Scrantan et al. 2005) –Magnification-magnification ZPJ & Pen 2005, 2006 (find ways to eliminate galaxy clustering and thus enables the lensing-lensing measurement)

Connecting fundamental physics with observations, KITPC, CMB vs. Lensing Primary CMB Weak Lensing Precision measurements: WMAP, PLANCK, CMB-Pol, etc. Precision measurements: CFHTLS, DES, SNAP, LSST, Pan-STARRS, SKA, Euclid,etc. Robust theory baryon+lepton physics Linear, Gaussian Accuracy: better than 1% Robust theory: Gravity Nonlinear, Non-Gaussian N-body simulations (+hydro) Information: C l (l<3000) z cmb = D Information: C l (l<~10 4 ), B(l 1,l 2,l 3 ), etc. z=1100, 10, D

Connecting fundamental physics with observations, KITPC, COSMOS-3D lensing －》 3D distribution of dark matter Lensing tomography

Connecting fundamental physics with observations, KITPC, Weak lensing and cosmological applications lensing power spectrum: observable Linear power spectrum: probes primordial fluctuations and tests inflation Nonlinear structure growth rate. Probes DM, DE, gravity and neutrino mass, Lensing kernel: tells us the distance- redshift relation and the curvature of the universe Refregier 2003 Schneider 2005 Munshi et al Hoekstra & Jain 2008

Connecting fundamental physics with observations, KITPC, CFHTLS:i band, 57deg 2 Fu et al also, Hoekstra et al Eventually, 5 bands, 170 deg 2 B mode: Measure of systematics Great progress! Cosmic shear has been measured robustly!

Connecting fundamental physics with observations, KITPC, Stage IV: LSST, SKA, Euclid, etc. ~20000 deg^2 billions galaxies sub-1% in power spectrum

Connecting fundamental physics with observations, KITPC, The dark energy task force recommends four  probes of the expansion: SN and BAO  probes of structure growth: weak lensing and cluster abundance Figure of merit for stage IV space projects Peculiar velocity as the fifth!! Part 2

Connecting fundamental physics with observations, KITPC, Distinguishing DE/MG: (1) Global fit Fang et al H. Zhang et al LCDM DGP DGP is less favored, or even ruled out

Connecting fundamental physics with observations, KITPC, Weak lensing/LSS and Yukawa-like gravity Dore et al arXiv:

Connecting fundamental physics with observations, KITPC, For future data, Zhao et al. 2008

Connecting fundamental physics with observations, KITPC, Independent methods to measure the distances. –D(EM): from EM waves (SN, BAO, maser, etc) –D(GW): from gravitational waves (GW) If gravity is GR in 4D, then D(GW)=D(EM) Otherwise, interesting things can happen –Example: if GW can leak into the 5th dimension, –D(GW)>D(EM) Deffayet & Menou, 2007 D(EM) D(GW) Distinguishing DE/MG: (2) Smoking guns

Connecting fundamental physics with observations, KITPC, To test gravity, we need to break the dark degeneracy I: MG and DE can mimic each other exactly in H(z) produced by any model There are always dark energy models with degenerate H! To distinguish between DE and MG, one must have LSS, besides the overall expansion of the universe!

Connecting fundamental physics with observations, KITPC, Consistency check of GR at cosmological scales The expansion rate The rate of structure growth Consistency relation observables

Connecting fundamental physics with observations, KITPC, Consistency check of GR: Real data!! Wang et al arXiv: Consistent with GR Expansion structure growth

Connecting fundamental physics with observations, KITPC, Wait a second Wang et al arXiv: Expansion structure growth Sign for MG? Sign for nothing?

Connecting fundamental physics with observations, KITPC, Ishak et al Also Knox et al Underlying gravity: 5D braneworld DGP Fit with GR Future surveys can do much better

Connecting fundamental physics with observations, KITPC, It is possible for a dark energy model to reproduce gravitational lensing and matter density fluctuations in DGP (Kunz & Sapone 2006) Kunz & Sapone 2006 See also Bashinsky 2007 Hu & Sawichi 2007 Two extra degrees of freedom in dark energy models the anisotropic stress pressure fluctuations Two extra degrees of freedom in modified gravity models Newton's constant relation between two potentials We need multiple probes of LSS to break the dark degeneracy II: modifications in gravity and DE/DM may mimic each other in some LSS

Connecting fundamental physics with observations, KITPC, Linear level large scale structure (LSS) in LCDM ， general dark energy models and modified gravity models. 4 perturbation variables: δ,v: perturbations in fluid Φ,ψ: perturbations in space-time Ma & Bertschinger 1995 Hu & Eisenstein 1999 ZPJ et al Amendola et al Holds for LCDM, DGP, f(R), Yukawa, etc. Extra perturbations in MOND scalar and vector fields

Connecting fundamental physics with observations, KITPC, If 3 or more independent LSS variables can be measured, modified gravity models can be unambiguously discriminated from DE/DM Jain & ZPJ, 2008 Break the dark degeneracy II One necessary condition for DE to mimic MG

Connecting fundamental physics with observations, KITPC, In the afternoon, I will talk about Large scale peculiar velocity as a probe of gravity Testing the Copernican principle

Connecting fundamental physics with observations, KITPC, Part 2 Peculiar velocity: a window to the dark universe Matter distribution in our universe is inhomogeneous Gravitational attraction arising from inhomogeneity perturbs galaxies and causes deviation from the Hubble flow v r v r peculiar velocity v=Hr

Connecting fundamental physics with observations, KITPC,

Connecting fundamental physics with observations, KITPC, What makes peculiar velocity special and important to probe gravity? At scales larger than galaxy clusters, only respond to gravity In linear regime, honest tracer of matter distribution Necessary for the complete phase-space description of the universe

Connecting fundamental physics with observations, KITPC,  GREAT attractor(s), with far more mass than expected, must exist in order to pull the Milky way at ～ 600 km/s with respect to CMB  Such gigantic structures should be no coincidence, if we believe in the cosmological principle Great attractor Shapely concentration Early applications of peculiar velocity: (1) A brave new world with gigantic structures

Connecting fundamental physics with observations, KITPC, Early applications of peculiar velocity: (2) road to the standard LCDM cosmology Largely based on peculiar velocity measurements of local and nearby galaxies, some cosmologists (e.g. Jim Peebles) argued that the the cosmological constant may exist and account for ~80% of the energy budget of the universe, in early 80s.

Connecting fundamental physics with observations, KITPC, How to measure peculiar velocity? Traditional method v r Subtract the Hubble flow to obtain the peculiar velocity v=Hr Measure the recession velocity from the redshift Measure the distance through FP,TF,FJ,SN, etc.

Connecting fundamental physics with observations, KITPC, A factor of 3 larger than the LCDM prediction Not so right asymptotic behaviour Watkins et al. 2008

Connecting fundamental physics with observations, KITPC, CMB photon free electron scattered CMB photon v p : bulk velocity scattering probability The kinetic Sunyaev Zel'dovich effect Recently, the South Pole Telescope (SPT) has for the first time discovered clusters, through the thermal SZ effect!

Connecting fundamental physics with observations, KITPC, Constraints of velocity from cluster kinetic SZ effect

Connecting fundamental physics with observations, KITPC, Measuring velocity from KSZ Allows statistical measurement of v p (v p power spectrum) Measure v p of individual clusters Requires other measurements to infer M g –Thermal SZ to have M g T –X-ray to have T ZPJ et al Haehnelt & Tegmark 1996; Kashlinsky & Atrio-Barandela 2000; Aghanim et al. 2001; Atrio-Barandela et al. 2004; Holder 2004

Connecting fundamental physics with observations, KITPC, SNe Ia as speed censors Peculiar velocity causes fluctuations in SNe Ia flux Noisy, but feasible. Already allow velocity measurement at z<0.1 Wang, Lifan. 2007

Connecting fundamental physics with observations, KITPC, SNe Ia as cosmic speed censors at intermediate redshift ~0.5 ZPJ & Chen, 2008 At z>0.1, lensing dominates over velocity Measure the 3D power spectrum of SNe Ia flux, in which noise can be significantly suppressed signal (velocity) Noise (lensing) z=0.5

Connecting fundamental physics with observations, KITPC, Redshift distortion and cosmology Peacock et al Kaiser effect induced by large scale coherent infall Finger of God induced by small scale random motion

Connecting fundamental physics with observations, KITPC, A sensitive measure of gravity Guzzo et al Acquaviva et al Spectroscopic redshift surveys Measure beta from the anisotropy Measure galaxy bias Obtain f Current measurements

Connecting fundamental physics with observations, KITPC, Spectroscopic redshift surveys measure (1) the expansion from BAO and (2) the growth rate from redshift distortion Amendola, Quercellini &Giallongo 2004 BAO BAO+RD RD helps to improve dark energy constraints  However, the improvement is not significant for future big surveys  Because if smooth dark energy, BAO and RD basically probes the same H(z)

Connecting fundamental physics with observations, KITPC, Strong tests on gravity Yun Wang 2007 See also Eric Linder 2007 DE and MG can have nearly degenerate H(z) But their structure growth rate can be very different

Connecting fundamental physics with observations, KITPC, Testing the consistency relation through spectroscopic redshift surveys Acquaviva et al =0 in GR+smooth dark energy BAO Redshift distortion

Connecting fundamental physics with observations, KITPC, Layers of assumptions/approximations e.g. Matsubara 2007 e.g. Tegmark et al. 2002,2004 Scoccimarro 2004 ZPJ et al. 2007, ZPJ 2008 deterministic bias e.g. Peacock et al. 2001; Guzzo et al. 2008; Amendola et al Linder 2007; Wang 2007 More uncertainties: Linear evolution Light cone distant observer assumption..... F: Lorentz or Gaussian scale independent galaxy bias e.g. Acquaviva et al. 2008

Connecting fundamental physics with observations, KITPC, On real data Tegmark et al on 2dF Tegmark et al. 2004, on SDSS One can measure the gg,gv,vv power spectra simultaneously. errors (vv)>errors(gv)>errors(gg)

Connecting fundamental physics with observations, KITPC, Forecast for future surveys the Square Kilometer Array (SKA) as an example Future surveys can detect (1) stochasticity in galaxy bias (2) scale dependence in galaxy bias We are no longer able to use the usual Kaiser formula. At such stage, more detailed check against current RD model and/or more accurate RD modeling are required ZPJ 2008 SKA, ADEPT, HSHS will map more than half the sky with accurate redshift measurements. Ideal for BAO and RD study

Connecting fundamental physics with observations, KITPC, MG parameterization equivalent X X Amendola et al Bertschinger& Zukin Caldwell et al Hu & Sawicki 2007 Jain & ZPJ 2008 Uzan 2006 ZPJ et al. 2007

Connecting fundamental physics with observations, KITPC, Testing the (generalized) Poisson Equation = Gravitational lensing from peculiar velocity ? Galaxy redshifts to recover redshift information (2D ->3D)

Connecting fundamental physics with observations, KITPC, Weak lensing Cosmic shear DES, LSST, SNAP, DUNE, SKA, etc. Cosmic magnification SKA Cosmic microwave and 21cm backgrounds Large scale peculiar velocities (bulk flows) Galaxy redshift distortion from spectroscopic redshift surveys Stage III: LAMOST, BOSS, etc. Stage IV: ADEPT, Euclid, HSHS, SKA, etc.  Other methods (KSZ, SNe Ia, distance indicators.... )

Connecting fundamental physics with observations, KITPC, A discriminating probe of gravity No dependence on galaxy bias No dependence on the shape and amplitude of the matter power spectrum, in the linear regime Scale independent in LCDM and QCDM, whose amplitude is completely fixed by the expansion rate Contains smoking guns of modifications in gravity and particle physics Changes in the amplitude Violation of the scale independence Poisson equation! Linear density growth rate galaxy-galaxy lensing redshift distortion f

Connecting fundamental physics with observations, KITPC, LCDM f(R) DGP MOND ZPJ, Liguori, Bean & Dodelson 2007 E G will be measured to 1% level accuracy within two decades Promising to detect one percent level deviation from general relativity+canonical dark energy model (if systematics can be controlled)!

Connecting fundamental physics with observations, KITPC, One can further construct an estimator of η≡-Φ/Ψ Lensing: Φ-Ψ; Peculiar velocity: Ψ ZPJ et al Velocity measurement forecasted for SKA ?

Connecting fundamental physics with observations, KITPC, ZPJ et al eta can be measured to 10% accuracy. Errors in eta is larger than errors in E_G Even so, eta can have stronger discriminating power, in some cases. η of DGP differs significantly from that of LCDM. (E G of DGP is very close to that of LCDM.) eta and E_G are complementary DGP with high Omega_m SKA forecast DGP MOND TeVeS dark energy with anisotropic stress

Connecting fundamental physics with observations, KITPC, The above argument is based on the cosmological principle, which is based on the belief of the Copernican principle  Our universe has no center ->homogeneous –The cosmological principle: our universe is homogeneous and isotropic. Described by the FRW metric  Violation of this principle and cosmological consequences –Dark energy as an illusion

Connecting fundamental physics with observations, KITPC, void The LTB universe  Lemaitre-Tolman-Bondi model –The universe is onion-like  If –we happen to live at the center – surrounded by a huge Gpc scale void,  then –SNe Ia become dimmer than what expected in FRW!  Violation of the Copernican principle fools us to accept cosmic acceleration, dark energy or modified gravity!

Connecting fundamental physics with observations, KITPC,  Dark matter, dark energy?  Modified gravity?  LTB with gigantic void in the center? Violation of the Copernican principle? .....

Connecting fundamental physics with observations, KITPC, Testing the Copernican principle  From CMB observations, we know that our universe is isotropic to us. Both FRW and LTB are acceptable.  How to know the universe viewed from other positions?  Incomplete list of novel ideas: –Reflecting mirrors and non-Blackbody spectrum (Caldwell & Stebbins 2008) –Speeding clusters (Garcia-Bellido & Haugboue 2008) –Distorted BAO (Clarkson, Bassett & Lu 2007, Zebin et al. 2008) –Constant curvature condition (Clarkson, Bassett & Lu 2007) ; Time drifting in the cosmic past (Uzan et al. 2008) –Slope of low z SN Ia distance moduli. (Clifton, Ferreira & Land 2008) –Small scale CMB (Clifton, Ferreira & Zuntz 2009) –Cosmic neutrino background (Jia & Zhang 2008)

Connecting fundamental physics with observations, KITPC, ， PRL arxiv: Ionized universe is a mirror to reflect CMB photons in other regions of the universe to us and thus tells us deviation from the Copernican principle Deviation from the blackbody

Connecting fundamental physics with observations, KITPC, Moving mirrors: the kinetic Sunyaev Zel'dovich effect Dust (matter) comoving frame Violation of the Copernican principle  Violation to the Copernican principle causes the relative motion between the CMB frame and the matter frame  Moving mirror causes the kinetic Sunyaev Zel'dovich effect prediction observations CMB frame In a homogeneous universe, no motion between the two

Connecting fundamental physics with observations, KITPC,

Connecting fundamental physics with observations, KITPC, Initial condition of the universe Physical principles The universe Nature of gravity, matter and energy Is the universe we observe a fair sample of THE UNIVERSE? the cosmological principle Nearly flat and homogeneous? Almost no defects? Adiabatic, Gaussian, nearly scale invariant fluctuations? single field Inflation ? ? ? ? The dark universe: nothing is impossible Bianchi? LTB? cosmicstring? multi-field? Gastrophysics? Nonlinearity? Backreaction?

Connecting fundamental physics with observations, KITPC, lensing SNe Ia BAO cluster abundance peculiar velocity CMB We are able to put everything together to reconstruct the elephant! the dark universe