DARK ENERGY RICHARD BATTYE JODRELL BANK OBSERVATORY SCHOOL OF PHYSICS AND ASTRONOMY UNIVERSITY OF MANCHESTER PHENOMENOLOGY & PRESENT/FUTURE OBSERVATIONS

PLAN OF TALK DARK ENERGY PHENOMENOLOGY CURRENT OBSERVATIONAL STATUS FUTURE COSMOLOGICAL TESTS - REVIEW CLUSTER SURVEYS WITH THE SZ EFFECT EFECTS OF DARK ENERGY MODELS : THERE IS MORE TO LIFE THAN w ! LINEAR PERTURBATIONS CMB ALONE SNe ALONE CMB + 2dF + SNe WEAK LENSING (TALK BY ANDY TAYLOR) NUMBER COUNTS P(k,z) - BARYONIC OSCILLATIONS X-CORRELATION BETWEEN CMB AND LSS AN EXAMPLE OF NUMBER COUNTS EFFECT OF PERTURBATIONS WORK WITH ADAM MOSS WORK WITH JOCHEN WELLER

SNe Ia BASIC OBSERVATIONAL SITUATION CMB 2dF/SDSS TRIANGULAR ARGUMENT +

DARK ENERGY PHENOMENOLOGY

DARK ENERGY PRESSURE TO DENSITY RATIO : w=-1 COSMOLOGICAL CONSTANT SCALAR FIELDS : QUINTESSENCE TOPOLOGICAL DEFECT LATTICES MODIFICATIONS TO GRAVITY ? SUPER-HORIZON PERTURBATIONS ! COSMIC STRINGS : w=-1/3 DOMAIN WALLS : w=-2/3 EASY TO MODEL GIVEN A LAGRANGIAN MODELLED AS A RELATIVISTIC SOLID ie A FLUID WITH RIGIDITY ASSUME FLAT UNIVERSE NB POSSIBLE NON-MINIMAL COUPLING TO GRAVITY

TWO CLASSES OF TESTS GEOMETRICALGROWTH OF STRUCTURE ONLY DEPENDS ON w ! ANGULAR DIAMETER DISTANCE LUMINOSITY DISTANCE GROWTH DEPENDS ON w AND ALSO ON THE PROPERTIES OF THE DARK ENERGY LINEAR REGIME : NON-LINEAR REGIME : (i) MASS FUNCTION (ii) SPHERICAL COLLAPSE (*) OFTEN GEOMETRIC DEPENDENCE AS WELL

EXAMPLES OF GEOMETRICAL TESTS TYPE Ia SUPERNOVAEPEAK IN CMB POWER SPECTRUM degeneracydegeneracy (l>100)

GROWTH OF DENSITY PERTURBATIONS NEWTONIAN THEORY N-BODY SIMULATIONS (VIRGO COLLABORATION) GROWTH HALTS AT L DOMINATION

INTEGRATED SACHS-WOLFE EFFECT t rec t 0 PHOTON TRAJECTORY DF FOR STATIONARY POTENTIALS : GRAVITATIONAL POTENTIALS DECAY ONCE DARK ENERGY DOMINATES : THIS MODIFIES CMB POWER SPECTRUM AT LOW l BREAKS GEOMETRICAL DEGENERACY - BUT MODEL DEP

DIFFERENT MODELS FOR DE EQUATIONS OF MOTION FOR A GENERAL FLUID NON-ADIABATIC (SCALAR FIELD) ADIABATIC (SOLID) (Hu; Weller & Lewis; Bean & Dore) (Bucher & Spergel; Battye, Bucher & Spergel)

LOW l CMB POWER SPECTRUM SCALAR FIELD SOLID W=-1/3 W=-2/3W=-4/3  CDM

PRESENT OBSERVATIONAL STATUS

CMB DATA ALONE BEST FIT MODELS ISOTROPIC SOLID DARK ENERGY NO PERTURBATIONS IN DE SCALAR FIELD DARK ENERGY THIS ANALYSIS FAVOURS w=-1/3 COSMIC STRING MODELS

SUPERNOVA DATA

CMB + 2dF + SNe SCALAR FIELD DARK ENERGY NO PERTURBATIONS ISOTROPIC SOLID DARK ENERGY NB : CMB ALMOST BURNT OUT IN TERMS OF DE, BUT ~2000 SNe CAN BE JDEM AND OTHERS MESSAGE : TAKE CARE WITH w !

FUTURE OBSERVATIONAL TESTS

NUMBER COUNTS EXAMPLES : RADIO SOURCES GRAVITATIONAL LENSES CLUSTERS (X-RAY, SZ, REDSHIFT SURVEYS) SKY COVERAGE SELECTION FUNCTION : FLUX LIMITED COMOVING NUMBER DENSITY - EVOLUTION

NUMBER COUNTS : CLUSTERS 1 per 200 deg 1 per 2 deg 10 per 1 deg 2 2 2

DEPENDENCE ON COSMOLOGY LCDM  w= z s=

SURVEY YIELD CALCULABLE TOTAL NUMBER OF OBJECTS LARGE REDSHIFT DEPENDENCE NOISE RATHER THAN CONFUSION DOMINATED CONTROL OF SYSTEMATICS NUMBER COUNTS : IMPORTANT FEATURES ACCURATE CORRELATION BETWEEN MASS AND PROXY (EG FLUX) POISSON ERRORS SEPARATE OPTICAL SURVEY? NEED TO AVOID CONTAMINATION IS THE MASS PROXY UNBIASED ?

BARYONIC OSCILLATIONS z=500 z=100 z=0 BARYONSCDM OSCILLATIONS TRANSFERRED FROM BARYONS TO CDM ( EISENSTEIN 2003) z=20

DEPENDENCE ON PARAMETERS w=-1/3 w=-2/3 w=-1 PLOTTED RELATIVE TO ZERO BARYONS BREAKS GEOMETRICAL DEGENERACY NON-LINEAR SCALE SMALLER AT HIGH z REQUIRES UNDERSTANDING OF BIAS

BARYONIC OSCILLATIONS : STATUS EFFECT DETECTED IN (i) SDSS LUMINOUS RED GALAXY SURVEY (ii) 2dF (Cole et al 2005) (EISENSTEIN et al astro-ph 2005)

X-CORRELATION : LSS & CMB ISW EFFECT LARGE-SCALE STRUCTURE bias selection function =0 for matter dominated universes CROSS-CORRELATE WHERE SENSITIVE TO ISW AND HENCE PERTURBATIONS IN DE COULD BE USED TO DISTINGUISH DE MODELS (CRITTENDEN & TUROK 1996)

X-CORRELATION : STATUS XRB CROSS CORRELATION (Boughn & Crittenden, Nature 2004) X-ray Background s(Boughn & Crittenden) NVSS (Radio) s(Boughn & Crittenden) 2MASS (Infra-red) 2.5s(Afshordi, Loh & Strauss) SDSS (Optical) 90-95% confidence (Scranton et al)  CDM prediction  m

FUTURE REDSHIFT SURVEYS LARGE NUMBER OF OBJECTS LARGE COSMOLOGICAL VOLUME ACCURATE REDSHIFTS BIAS - WHAT IF IS SCALE DEPENDENT? PLANNED SURVEYS - AN INCOMPLETE LIST POISSON ERRORS ARE DOMINANT SOURCE OF ERRORS WIDE AREA DEEP SURVEYS PHOTOMETRIC V SPECTRSCOPIC Dark Energy SurveyOPT10^8 gal to z~1PHOTO-z 2009 DarkCam on VISTAOPT/IR "PHOTO-z 2009 KAOSOPTout to z~3.5!SPEC-z 2012 LSST OPT PHOTO-z2012 SKARADIO10^9 gal to z~1.5 SPEC-z2015

CLUSTER SURVEYS USING THE SZ EFFECT

THERMAL SUNYAEV-ZELDOVICH EFFECT  T INDEPENDENT OF z :

QUANTIFYING THE THERMAL SZ EFFECT x = f/56.4GHz

TARGETED OBSERVATIONS RYLE TELESCOPE VERY SMALL ARRAY (Lancaster et al 2004)

1ST GENERATION INSTRUMENTS ~ 50deg 8x3.5m ANTENNAE OWENS VALLEY, CA =30GHz & 90GHz LINK WITH CARMA 10x3.7m ANTENNAE CAMBRIDGE =15GHz Tsys=25K,  =6GHz RYLE TELESCOPE AMI SZA 2 - INTERFEROMETERS

2ND GENERATION INSTRUMENTS -LARGE AREA OR VERY DEEP SURVEYS GROUND BASED : SPT, ACT, APEX-SZ SPACE MISSIONS : PLANCK MULTI-ELEMENT FOCAL PLANE ARRAYS HIGH RESOLUTION ~1', deg BOLOMETERS ~150GHz TOTAL POWER -NEED A DRY SITE ~ CLUSTERS MULTI-FREQUENCY 30GHz-850GHz LOW RESOLUTION ~5'-10' POWERFUL REJECTION OF SYSTEMATICS ALL-SKY ~ NEARBY CLUSTERS 2

INPUT PHYSICS : SIMPLE MODEL e e e e e e e e e e SPHERICAL AND VIRIALIZED ISOTHERMAL DISTRIBUTION IN M & z GAS PROFILE SPHERICAL COLLAPSE NUMERICAL SIMULATIONS CORE RADIUS VIRIAL RADIUS

COMPUTING THE SELECTION FUNCTION MAXIMAL 8' 4' 2' 1' 16'

COSMOLOGICAL DEPENDENCE DIFFERENCE BETWEEN L AND w= z FOR 1 sq. deg AT LEAST 750 sq deg NEEDED

SPT PLANCK SIMULATED DATA AMI/SZA

SIMULATED CONSTRAINTS CENTRAL CONTOUR CORRESPONDS TO SPT FIDUCIAL MODEL: w= z

COMPLEMENTARITY TO SNe Ia SNe SZ

+16% -12% MASS-TEMPERATURE RELATION

CONCLUSIONS DARK ENERGY APPEARS TO EXIST GOOD MICROSCOPIC MODELS SCARCE PHENOMOLOGICAL DESCRIPTION REQUIRED IN PRINCIPLE MANY WAYS TO TEST IT MANY SYSTEMATIC ISSUES TO BE ADDRESSED VARIATION IN w DIFFICULT DARK ENERGY EXPERIMENTS COST ~ 10 MILLION £/$/EUROS