Dark Matter, Dark Energy: puzzles & alternative solution

Review Success of LCDM Most user-friendly concise description Better understood than its alternatives

There are challenges to LCDM Some confident of LCDM being ultimate theory Alternative receipes worth pursuing?

HongSheng ZHAO

SUPA, Univ. of St. Andrews

Carroll’s KITP talk 2006

DM+DE+GR: 3 pillars of universe, baryons & neutrinos are accidental tracers of dark universe…

Successful larger scale (>100Kpc) Precision science! (also <100AU scale)

Solar system GR tests, Pulsars, CMB peaks Except: (vacuum) DE is a fudge factor

Mixed success in galaxies No Single robust DM candidate emerged

in 60 years CDM, WDM, SIDM, FDM, RDM, BDM etc.

all challenged by some observations

Usual NASA Headline: astronomers prove “DM+DE+GR”

i.e., we “see” (via lensing, dynamics, candles, CMB)a misbalance of Einstein’s Equation:

Observed space-time Curvature Gtt

- Energy Density of Known source Ttt = Unidentified Source Ttt > 0

Ideas to restore Balance:*Assume w=0 pressure-less fluid dark matter*Assume w=-1 Cosmological Constant, inflaton fluid*Vary w evolving fields of (modified) metric-coupling

detect an energy residue

E/c2 – mknown > 0 in late time universe

We “see” extra metric perturbations:CDM or neutrinos or clumps of energy?

A520 (Cosmic Train Wreck) Bullet: Clowe et al. (2006) NASA release

Acceleration of universe/galaxies:Einstein’s Eq. needs N new terms

1. RH approach ⇒ Various B/I/H/W/C DM +Inflaton+Vacuum Energy Source

2. LH approach ⇒ Modified R+1/Rn gravity e.g. Cosmological cst n=0,

Interchangable, RH formulation easier, but N~1 preferred

If inert gas gives few photons, interacts so weakly astronomers see via gravity with photons only…

DM in the Sun, galaxies, universe Not in dense Earth, Neutron stars …

Or Gravity is modified (0-25%) as f(R): function of density Astronomers cannot tell DM or Vacuum fields even after lab fusion 4H HeliumDM, lab proof

NeonLight

He, Ne

Merits of Cosmology using 3, 2 or 1 pillars Could Dark Matter = Vacuum Energy = Inflaton Field = Projections of a 0.001eV-Particle/Fluid/Field + GR ? = A Non-Linear Gravity

Perspective: Astronomers havethe biggest vacuum lab of gravity

“Coincidences in DE-DM: Clues for a simple alternative?”

Zhao’07 (ApJ Letters Dec’07, arXiv0710.3616)

just some numbers or

In 4D-Metric, what is modified gravity?

Space-time metric field in vacuum

SEP-coupled to

all specifies of non-SEP-mutually-coupled matter

What is new? GR+ vacuum fields

Gravity modified twice by Einstein1. Add cst c2 to Newton’s apple mc2 = E2. Add cst to his own theory c2

3. made dynamical scalar field of vacuum (DE) to accelerate universe uniformly 3++? recycle DE as vector field, collapse as

DM to accelerate stars in galaxies? Solve DM puzzles?

A Doesn’t-Matter <0.1 universe (~ baryons ~ known neutrinos =0.005-0.1)compatible with LHC etc. in 8 years

Abundance set by ~ 256 coupling-consts of SUSY/MSSM

Room for Vacuum!

Still premature?

Why should WE at ICGC care?

Isn’t DM a temporary problem of Too poor to run LHC sooner? Lack

accurate prediction of SUSY theory? Poor accounting by astronomers? Poor resolution of galaxy simulators?

NOT Quite! Uncertain DM surely tells us nothing

new about how space-time works?

Cosmological Simulations

Cusps

Satellites

Fits well with LSS

10 year Crisis:

P(k)=kn

Moore et al. (1999)

Halo with 2x1012 M⊙

the substructure ProblemSUBHALOS IN A RICH CLUSTER AND A MILKY WAY-SIZED HALO

Halo with 5x1014 M⊙

Moore et al. (1999), Klypin et al. (1999): Where are all the missing satellites?

Rocks in LCDM universe: dumps of angular momentum

Overpredicts satellites: survive tide-- including SDSS satellites (Cambridge group’07)

-- WDM helps on Draco, but barely enough to cause quasar-lensing flux fluctuations or anomalies (Metcalf & Zhao 2002, ApJL, Miranda & Maccio’07 for reliable radio quadruple lens)

Overpredicts Bulges in disks: dense-- simulations of Steinmaintz’07

Overpredicts cusps: irreversible bary -- Gnedin & Zhao 2002, MNRAS, Read & Gilmore 2003, MNRAS

Slowly grow a massive disk/bulge in NFW halo Lowest ang. J Highest init. Mb/Mdm

Rapidly remove all gas (by SNe with top-heavy IMF)

“Spring out” some DM: STILL To CUSPY!

====??===

Cusp to Core: 1,2,3,…10Dwarf Feedback is limited

Gnedin & Zhao’02: no core after 1-outflow (strongest)

Read & Gilmore’03: core at last after 3-resurrections with fb =0.2 each time

Or use 10 BHs …

C.D.M.: C for Cold, Collisionless, or Contradiction Doesn’t Matter? DM is collisionless as galaxies: Bullet Cluster (Bradac et al.’07) DM is collisional as gas: Abel 520 (Mahdavi et al. 07)

warmer DM m<0.5kev: cores in Ursa, Fornax colder DM m>2kev: substructure in lensing, Ly-alpha (Metcalf & Zhao’02, Maccio et al.’07)

Tidal Dwarf Galaxies want dark CO disks (Bournard etal. Science) Milky Way wants extended halos (Klypin, Zhao, Somerville’02)

… Dilemma removed if DM isn’t a precisely w=0 fluid or field ~ some metric bending field like Photon, inflaton & DE

Budget Deficit ofZwicky’s “Dark Matter” (1933)

MACHO microlensing surveys’92-02 Jupiters/BrownD ~ stars, Omega~0.01

Neutrino oscillation’98 (SuperK, LSND’93-98, MiniBooNe’07) ~ low

Neutralino annihilation & scattering: EGRET GeV excess’97,DAMA modulation’97 prefer big cross-section Omega~0.01

Low-Energy Vacuum, Omega~unity?

Small rarely adds up to big!!

EGRET evidence for DM annihilation

Enter~ m04 ! m0=0.001eV=10-30msusy

scale of energy clumps in-of space-time

Just Six Numbers --Rees Just 5 Numbers of gravity

3+1: dimensions we live in N: rela. strength of gravity to E&M epsilon: metric fluctuation of vacuum (inflaton) Lambda: energy scale constant of vacuum Omega: dark matter

low-energy Vacuum Higgs or high energy SUSY Higgs?----------------------------------------------------- +Q: rate of Nucleosynthesis + age of universe + 3K

CMB photons + neutrinos + … [STANDARD MODEL PARAMETERS ~ 20] ….[MSSM ~ 256 parameters ]

Merits of Cosmology using 3, 2 or 1 pillars Could Dark Matter = Vacuum Energy = Inflaton Field = Projections of a 0.001eV-Particle/Fluid/Field + GR ? = A non-linear gravity

DE:DM=3:1 (expect 0-Inf:1)DM:Bar=8:1 (expect 0.01-100:1)

“Coincidences in DE-DM: Clues for a simple alternative?”

Zhao’07 (ApJ Letters Dec’07, arXiv0710.3616)

just some numbers or

A recipe for Value-Added DE to give Effective DM+DE

Lagrangian Density

= Lknown matter + LK +Lcurvature

Vector Field = Vacuum Flow = metric mesh “softening” fluid [collisonless, tracks mass

like dielectric-MOND, adds stress to depress the metric]

LDM + LDE +

Linflaton

Covariant Stress of Metric-tracking Fluid Four-Velocity Ua=Aa/mc2

Zhao (ApJ Letters, Dec’07 Issue)

Extra stress to the metric below a stress scale P0

=(0.001eV)4

Zhao’07 (ApJL)

Einstein Eqs: Poisson+Hubble

solar (N)~0, (n)=2-n, m4 ~~L(0)~(na0)2 ~9P0

<- n=3, (x)~(1+x/n)-n ,a0=1A/s2 , N=105

solar (N)~0, (n)=2-n, m4 ~~L(0)~(na0)2 ~9P0

<- n=3, (x)~(1+x/n)-n ,a0=1A/s2 , N=105

Parameters & Predictions n,N,a0 are the only 3 free parameters

gravity tracks baryons approximately during feedback NOT rigorous because time-dependent systems

(CMB, tidal merger) DE/DM properties of vacuum space-time

New LHC particles could exist, but are rare New modes of gravitational waves

Cosmological Constant and eff. DM Come Out Naturally

Aether Fluid w = 0 (in static or matter-dominated), w=-1 (late universe)

Vacuum Between Two sheets: gravitation/E&M corrected

Lambda: sea of virtual pairs of m0

P0=(m0c2)/(h/m0c)3 =(0.001eV)4= (cH0)2

Freeman’s law: disk surface density. P0=[a0/(8G)] a0 =(130g/m2)(1A/s2)

Dielectric – gravity link !!!

Einstein-Maxwell,

Einstein-Aether theories

Durality: Photon as particle and a Vector-Field

+Q

V- fluid + GR + Baryonsfits 50 x 50 data points ...

Bruneton, Famaey, Gentile, Zhao (2007, PRD)

VDM4/GMbary

=(gDM/gbary ).gDM

~a0 ~1/2

Su & Zhao

My V- fluid is like CDM, but fits galaxy data better… Compatible with

any neutralinos from LHC’2012, any neutrinos from KATRIN’2009, inflation induced perturbations, BBN, Solar system PPN, Bullet Cluster lensing/speed/annihilation …

Microlensing in MW Bar, RAVE escape speed, … Tidal Dwarf Galaxies, SDSS satellite velocities

Free Parameters: n, N Perfect

~ (0.001eV)4 ~ 9 a02 ~ 3 bar

cosmic MDM/Mbar~2n ~ 8 nearly all rotation curves

Tombstones of in Graveyard of Gravity: !!GO Back to GR!!

Various Lagrangians of the Vacuum (Renaissance 2005-2007)

Solar system, Black Holes, Waves

MOND: Lensing Dark Energy, CMB,

inflation/string …unknowns in co-

variant frameworks Jacobson’97, Bekenstein’04, Sanders’05, Ferreira’07, Zhao’07 …

B’04 (cite 170)

High-risk ideas… after packaging by a decent theory…

Milgrom’83 (cite 417)

Zwicky’33 (cite 236)

Co-variant Bekenstein’04 (cite 170)

Universal NFW’97

(cite 1997)

gravity = a0 somewhere in all objects 10-1pc-109pc

Spirals Ga0 ~ Rotation V4 /BaryonMass

GlobularCluster, MolecularCloud, dwarf, Ellip, X-Cluster a0 ~ Velocity2 /Length scale ~ cH0/6 ~ 100Msun/pc2

My covariant model predicts tight baryon-DM-DE correlations: (nearly) history-independent, but environment-dependent

Vacuum Fluid fits as good as LCDM,

but no “L” no “CDM”

Collaborations with Su, Skordis. Mota, Angus, Famaey, Shan, Halle, Gentile

SNeIa distance-SNeIa distance-zz

Dwarf & HSB Vcir(R)

Proof of GR+LCDM in WMAP & Bullet: countered by MOND+our temporary ignorance of neutrinos

Toy TeVeS models Skordis et al’05 PRL, Angus etal.’07 ApJL, Feix et al.’07

to wait for KATRIN’09 neutrino experiment <2eV,

to win time to study effects of four-velocity freedoms (e.g. the J-term in V model)

Spherical TeVeS CASTELS lens

Zhao, Bacon, Taylor, Horne (2006,MNRAS)

Non-covariant MOND means simply effective DM

Every mass hosts the potential of an effective DM halo (Flattened Isothermal), truncated by its neighbours

Geodesic eqs as GR with factor-2 for lensing (but Geff varies)

State-of-art galaxy bar formation: in DM and non-covariant MOND

Non-covariant MOND has zero freedom, falsifiable 1-to-1 relation Intergalactic DM<0

Check if your chi^2 (from tidal stream or lensing) favors DM positive everywhere.

Identical Baryons mandate identical DM Spot differences in

twins (globulars, dwarfs, galaxies …)

History-independent potential

A Fake Hybrid Spiral Galaxy

Scarpa; http://xxx.lanl.gov/pdf/astro-ph/0601478

MOND fails to fit (Good !!) DM fits fine

Stars

GasGas

Stars (with smaller M/L)

Shoot, but avoid well-proven traps due to External Field Effect

Vcir NOT flat Vesc NOT infinite Potential NOT as flat as disk Galaxies NOT always on Tully-Fisher …

! Attraction due to environment (cluster/filament) is important !

EFE mimics LCDM tidal harassment

Read our 4p manual for EFE traps in MOND

I

Wu, Famaey, Gentile, Combes, Zhao et al. (2007, ApJ Letters)

EFE mimics LCDM tidal harassment

Internal potential is deep/shallow if more/less isolated Tend to create 2nd generation of stars in

distant globulars? Dwarfs evaporate in Coma Cluster

(mimic LCDM harassment)

Vulnerable because MOND predicts

History-independent DM potential Both Tidal Dwarfs and Ordinary dwarfs,

have DM effects (The Science article; Gentile et al. 2007, A&A, Letters)

Oblate Halos in disks …

Lack of Dyn. Fric. & Mergers …

Title: Resurrection from the Graveyard of Gravity:       Renaissance of MOND as Dark Energy

Abstract:While under-developed historically due to the lack ofa relativistic framework, Milgrom's empirical formulais a magical crystal ball, which forseed the ubiquitous existenceof an EFFECTIVE Dark Matter and Dark Energy well beforethe more physically motivated LCDM parametrization of the cosmos.The MOND formula works accurate in nearly all spiral galaxies, andis order of magnitude correct in clusters of galaxies and in cosmology.This is a remarkable achievementconsidering the tiny amount of man power and computational power spenton MONDified gravity research.  Theoretical physicists have recentlyimbeded MOND in a fully relativistic framework.

I present new results which suggest thatMOND is fundementally a hypothesis about the vaccum andspace-time, which reduces to Dark Matter effects in collapsedgalaxy-like structures and Dark Energy effects in uniform cosmology.A proof of existence of dark matter(like known neutrinos or the promising LHC SUSY particles)is often not incompatible with a range of gravity theories,and is not a proof of General Relativity. The even more ellusive nature ofthe cosmological constant is the stronger motivation for modified gravity.

Aim of This Talk

Explain MOND as Empirical Law As a co-variant gravity As Vacuum Energy (V-Lambda) As DM

Relation to LHC, DM annihilation Relation to Neutrino