ObservationalObservational CosmologyCosmology -- thethe DarkDark UniverseUniverse --
Ariel Goobar Physics Department, Stockholm University Evidence for DM Evidence for DE Cosmology primer Hands-On supernova cosmology
Cross-cutting techniques: CMB, Lensing, LSS, BAO New SN data-sets
Ongoing and Future projects
2 CosmologyCosmology && NewNew PhysicsPhysics
• Cosmic inventory: best evidence for new microphysics!
3 TheThe ””oldold”” newsnews
Dark Matter Rotation curves of spiral galaxies: pioneered by J.Oort in 30’s
Y. Sofue, 1997
mv 2 (r) Centripetal force F = GMN visible c r ⇒≈vr() M(r)m r Gravity: F = G g N r2 ButBut rotation rotation curves curves are are flat! flat! FF= & MrM ( ) = cg visible ⇒⇒DarkDark Matter! Matter! 5 DarkDark MatterMatter Galaxy contents and rotation curves
DarkDark mattermatter needed needed to to explainexplain rotation rotation curves curves ofof galaxiesgalaxies
Jungman et al, Phys. Rep. 267(1996)195. 6 DarkDark MatterMatter atat largerlarger scalesscales:: clustersclusters ofof galaxiesgalaxies
F.Zwicky (1933) measured Coma cluster individual velocities of galaxies in Coma and concluded that ~10 times more 7 mass than Mvisible needed DarkDark MatterMatter inin action:action: thethe bulletbullet clustercluster
DM separarted from the gas: MOND does not work!
Clowe et al 06 8 SoSo whatwhat’’ss goinggoing on?on?
”Collisionless” matter needed= DM
9 TheThe leadingleading candidatecandidate:: lightestlightest SUSYSUSY particleparticle
Supersymmetri: from particle physics and string theory.
Normal particles / fields Supersymmetric particles / fields Interaction eigenstates Mass eigenstates Symbol Name Symbol Name Symbol Name q = d,c,b,u,s,t quark q˜ L ,q˜ R squark q˜ 1,q˜ 2 squark l = e, µ,τ ˜ ˜ ˜ ˜ lepton l L ,l R slepton l 1,l 2 slepton
ν = ν e ,ν µ ,ντ neutrino ν˜ sneutrino ν˜ sneutrino g gluon g˜ gluino g˜ gluino W ± W-boson W˜ ± wino ± χ˜ 1, 2 chargino m ˜ m } H Higgs boson H1/2 Higgsino B B-field B˜ bino ⎫ 3 3 3 ⎪ W W -field W˜ wino ⎪ 0 ⎬ χ˜ 0 H1 Higgs boson ˜ 0 Higgsino 1,2,3,4 neutralino 0 H1 ⎪ H Higgs boson 0 2 H˜ Higgsino ⎪ 0 Higgs boson 2 ⎭ H31 R=+1 R=Š1 Perfect DM candidate!
10 TheThe ””newernewer”” newsnews
Dark Energy SCP:Perlmutter et al + High-Z Team:Riess et al
Supernova Cosmology Project (SCP)
12 TheThe breakthroughbreakthrough!!
13 ExpandingExpanding UniverseUniverse
• The equations governing the expansion of the Universe are the Friedmann equation (FE) and the acceleration equation. • These are derived from the Einstein equation: 1 R −−Λ=gR g8π GT µνµν2 µν µν
applied to a homogeneous and isotropic Universe, i.e. in the RW metric. • Friedmann equation:
2 ⎛⎞. aGk8π H 2 = ⎜⎟=− ⎜⎟aa3 ρ 2 ⎝⎠
• Acceleration equation:
.. aG4π =−() +3p a 3 ρ
• Where ρ(t) and p(t) are the energy density and pressure driving the expansion of the
Universe. H is the Hubble parameter (H0 corresponds to the present value). 14 TheThe ContentsContents ofof thethe UniverseUniverse
• There is a third equation that can be derived from the Friedmann equation and the Acceleration equation, the Fluid equation (also called continuity equation):
. ρρ+ 3(Hp+= )0 • The energy density is made up of different types of matter characterized by their equation of state: pw= ρ • At least three types of “fluids” are used to describe the energy content of the Universe Radiation, w=⅓ non-relativistic matter, w=0 vacuum energy, w=-1. • Inserting the equation of state into the acceleration eqn into we see that:
.. aG4π =−()13 + w a 3 ρ
• Thus, a fluid with w<-1/3 (if dominant) can make the universe accelerate . As we shall see later on, other kinds of energy types with negative w have been suggested, these all fall under the general name “Dark Energy”. 15 CriticalCritical densitydensity
• It is often useful to rewrite the energy density components in units of the critical density: 3H 2 ρ c = 8πG • How do we see that this should be the critical density? By examining the Friedmann equation for the flat case k=0 which corresponds to the critical density. • In a Λ=0 universe. If k>0, will eventually hit zero i.e bounce, if k<0 the density is under-critical and does not have a singularity. • The present value of the critical density is: ρc=1.9h2×10-29 g/cm3 2 11 3 = 2.8 h ×10 M☼/Mpc = 11.3 h2 protons/m3 • The energy density terms are diluted with the expansion of the
universe as [a0=a(t0); t0 = now]:
3(1+w ) ⎛⎞a0 3(1+w ) ρρ==+ ρ00⎜⎟ (1z ) ⎝⎠a 16 CosmologicalCosmological parametersparameters
ρ0 8πG Ω=M c = 2 ρ0 ρ003H 8πG Ω Xxxx==⋅2 ρ ;where pwρ 3H0 k Ω=−K 22 aH00 Λ w =−1; ΩX ≡ΩΛ = 2 3H0 17 LuminosityLuminosity DistanceDistance
cz⋅+(1 ) ⎛⎞zE dz dF=ΩE ⎜⎟ LK⎜⎟∫ Hz() ΩK ⎝⎠0
• where F(x) = sin(x) for a closed universe, sinh(x) for an open universe and x for a
flat universe. In the latter case the ΩK terms are set to 1.
22⎡⎤ 3 2 HH=Ω++Ω++⋅Ω0 ⎣⎦MK(1 z ) (1 z ) fz ( ) X where ⎡⎤z 1()+ wx fz()exp3= ⎢⎥∫ dx ⎣⎦0 1+ x
18 WhatWhat isis aa SNSN Ia?Ia? AA ToyToy ModelModel
19 TychoTycho’’ss SNSN 1572:1572: aa companioncompanion foundfound??????
20 HowHow doesdoes aa TypeType IaIa SNSN looklook like?like?
Soon after the explosion SN2003duSN2003du
Credit: V.Stanishev 22 SupernovaSupernova classificationclassification
23 SNIaSNIa spectrumspectrum
Fingerprint of Ia’s: Fλ Si 6150 Å feature
λ
24 SNSN opticaloptical lightcurveslightcurves
SNIa SNIIp 25 ShapeShape--brightnessbrightness relationrelation
26 ””StandarizeableStandarizeable”” candlecandle
• Typical spread in Type Ia brightness is about 40% • After shape-brightness correction, SNIa are standarized to about <15% standard deviation in brightness...... Corresponding to ~7% precision in distance.
27 Recent estimates of H0 from Type Ia Supernovae
Credits: Saurabh Jha 28 SNSN--cosmologycosmology tutorialtutorial
Cosmology fits
Search Lightcurve
Hubble diagram
Reference
29 ExampleExample ofof highhigh--redshiftredshift SNeSNe
30 SNIaSNIa ratesrates
31 SNIaSNIa ratesrates
Exposure length
32 AstronomicalAstronomical measurementsmeasurements
• The observed bolometric magnitude (integrated over all wavelengths)
m(z) = M + 5 log10(c/H0) +25 + 5 log10D’L(z;Ω’s)
M is the magnitude of the object if placed at 10 pc; DL is measured in Mpc and D’L=DLH0
• In practice, astronomical measurements are done through broadband filters: K-corrections are needed in order to compensate for spectral differences.
• Corrections for extinction are often applied • In the case of type Ia SNe, there is also a brightness-shape relation that is taken into account
mY(z) = MW host MX + 5 log10(c/H0)+25+ 5 log10D’L(z;Ω’s) + 25 + KXY(z) – AY –AX + α(s-1) 33 KK--correctionscorrections
34 TypeType IaIa supernovaesupernovae asas standardstandard candlescandles
and how we learn about Dark Energy Statistical uncertainty: Redshift dependence
AG & Perlmutter 95 95 36 MeasurinMeasuringg thethe eqneqn ofof statestate parameterparameter ””ww”” withwith SNIaSNIa
37 55 AD:AD: concordanceconcordance modelmodel (see also Tonry et al 2003, Barris et al 2004)
ΛΣΣ ?ΙΣΩ
+0.06 ΩΛ = 0.75−0.07 ± 0.04 38 HandsHands--OnOn SNIaSNIa cosmologycosmology
What may go wrong in the world of astrophysics ((KnownKnown)) systematicsystematic effectseffects
• SN brightness evolution • Shape-brightness relation Astrophysics of supernovae • K-corrections and SN colors
• Non-Type Ia contamination Selection effects,contamination • Malmquist bias
• Host galaxy dust properties • Intergalactic dust Line of sight effects • Gravitational lensing • Exotica:axion-photon oscillations, etc
• Instrumental corrections Measurement • Absolute calibration issues • Lightcurve fitting technique/host galaxy subtraction
• … 40 ExploringExploring thethe ””StandardStandard CandleCandle”” CheckinCheckingg thethe standardstandard candlecandle:: lowlow vsvs highhigh redshiftredshift
Goldhaber el al 2001
42 OngoingOngoing EuropeanEuropean SNIaSNIa Network:Network: upup toto nownow >15>15 nearnear--byby SNeSNe:: e.ge.g SN03duSN03du
Infrared spectra between -13 and +30 days
Optical spectra between -13 and +376 days Stanishev et al 2006 43 SpectralSpectral diversitydiversity:: couldcould bebe usedused toto sharpensharpen ””standardstandard candlecandle””??
high-velocity Ca II ~21000 km/s
44 AsymmetriesAsymmetries linkedlinked toto spectralspectral diversitydiversity??
D.Kasen
45 InteractionInteraction withwith companioncompanion starstar??
Marietta et al. 2000 46 OngoingOngoing highhigh--statisticsstatistics lowlow--zz projectsprojects
• Supernova Factory: search + optical spectrophotometry of a few hundred SNe. (Search at Palomar, IFU follow-up at UH2.2m) • Carnegie Supernova Project: high precision optical and NIR lightcurves of ~200 SNe (z<0.07). Already ~150 SNe, about ½Ia’s.
47 FirstFirst SNSN--factoryfactory resultsresults Aldering et al
Target Redshift Epochs Timespan Comments
2004dt 0.020 27 93 days HST UV
2004gc 0.031 16+1 58 days
2004ef 0.031 11+1 46 days HST UV
2004gs 0.027 11+1 48 days
2005bc 0.012 16 51 days
2005M 0.022 11 40 days HST UV
2005bg 0.023 11 29 days
2005ag 0.029 9 51 days
2005L 0.070 7+1 28 days
2004gk 0.000 8 31 days
2005bl 0.024 8 20 days
2005ak 0.027 4+1 8 days
2004il 0.107 4 11 days SDSS
2005cf 0.001 2+ 3+ days HST UV
2005cg 0.031 1+ 0+ days 48 CarnegieCarnegie SupernovaSupernova ProjectProject
49 HighHigh--QualityQuality lightcurveslightcurves inin opticaloptical andand NIRNIR
50 SupernovaeSupernovae atat z~0.5z~0.5
New data-sets SpectroscopicSpectroscopic teststests ofof standardstandard candlecandle
Low-z average CaII (3900) subluminous velocity
z∼0.5
overluminous subluminous
Folatelli et al, Garavini et al , Lidman et al 52 LargeLarge ongoingongoing 0.2 • ESSENCE at CTIO 4-m: to collect ~200 SNIa • CFHT (3.7-m) SuperNova Legacy Survey: 5 year ”rolling search”in (u)griz. Up to ~1000 spectroscopically confirmed SNIa. 53 HugeHuge Cameras!Cameras! CTIO:CTIO: 88 CCDCCD’’ss ½½°°xx½½°° 54 CFHT:CFHT: 4040 CCDsCCDs,, 44 timestimes biggerbigger!! 55 SNLSSNLS progressprogress 56 CFTHCFTH--SNLSSNLS 57 astro-ph/0510447 58 1st1st YearYear HubbleHubble diagramdiagram • 71 high-z SNe discovered at CFHT • 44 low-z SNe from Hamuy et al, Riess et al & Jha et al (Cfa1 & Cfa2) • High-z: SDSS ugriz filter system • Derived ”intrinsic” scatter in CFHT sample 0.12 mag • Excellent agreement with concordance model (ΩM = 0.263± 0.042 for flat universe) 59 ΩΩΛ 60 ww0 61 wwa 62 MMscript 63 TheyThey shouldshould allall bebe fittedfitted atat samesame time!time! 64 ENDEND OFOF PARTPART II Evidence for DM Evidence for DE Cosmology primer Hands-On supernova cosmology Cross-cutting techniques: CMB, Lensing, LSS, BAO New SN data-sets Ongoing and Future projects 66 CrossCross--cuttingcutting techniquestechniques CMB,Lensing,baryon oscillations,LSS,... WeakWeak GravitationalGravitational LensingLensing Distortion of background images by foreground matter Unlensed Lensed Credits: R.Ellis 68 69 RecentRecent weakweak lensinlensingg resultsresults fromfrom CFHTLSCFHTLS 70 AskAsk thethe lensinglensing guru!!guru!! 71 72 The principle behind the CMB The limit of the visible Universe. Given by how far light can have travelled since the beginning of the Universe. The visible Universe At an age of about ½ million years the Universe became transparent for light. Observers TheThe cosmic cosmic microwave microwave backgroundbackground radiation radiation was was The CMB sentsent out out in in all all directions. directions. WhereeverWhereever we we look, look, we we see see the the lightlight that that was was sent sent out out in in the the directiondirection of of us us (about (about 14 14 billionbillion years years ago). ago). 73 ShortShort historyhistory ofof CosmicCosmic MicrowaveMicrowave BackgroundBackground (CMB)(CMB) •• GamowGamow predicted predicted the the CMBCMB inin 19461946 •• PenziasPenzias och och WilsonWilson discoverddiscoverd it it inin 19651965 andand gotgot thethe NobelNobel prizeprize in in 1978.1978. •• Dicke,Dicke, Peebles,Peebles, RollRoll andand WilkinsonWilkinson explainexplain Penzias Penzias andand Wilson’sWilson’s measurements measurements inin 1965.1965. Arno Penzias and Robert Wilson, Nobel prize 1978 74 ise” ”no mic Cos red! ove disc 75 76 The CMB – A perfect black body spectrum COBE Congratulations to J.Mather2006 σ & G.Smoot, Νοβελπρισε:ϑ This year’s Nobel laureates! 77 14 years ago… 78 CMBCMB anisotropiesanisotropies:: thethe WMAPWMAP resultsresults • Flat geometry: ΩM + ΩΛ = 1.04 ±0.05 • Low baryon content 2 Ωbh = 0.024 ± 0.005 (cf 0.019 ± 0.02) Credits:WMAP 79 CosmicCosmic MicrowaveMicrowave BackgroundBackground The small angle -causal- fluctuations •• Balance Balance between between infall infall and and pressure.pressure. •• Acoustic Acoustic oscillations oscillations arise. arise. •• Photons Photons from from the the dense dense and and sparsesparse areas areas have have different different temperature.temperature. Two Two effects effects compressioncompression (heating) (heating) + + redshift.redshift. •• The The typical typical distance distance between between coldcold and and hot hot areas areas act act as as a a standardstandard ruler ruler and and extend extend aboutabout 1 1˚˚onon the the sky. sky. Legendre multipoles: l~π/θ~200/Ω-½ 81 From Wayne Hu. The geometry of the Universe TypicalTypical distancedistance betweenbetween coldcold andand hothot spots:spots: FlatFlat universe:universe: θθ~~ 11˚˚ OpenOpen universe:universe: θθ<< 11˚˚ ClosedClosed universe:universe: θθ>> 11˚˚ 82 From Wayne Hu. AngularAngular PowerPower SpectrumSpectrum 83 closed CMB alone tells “Geometric Degeneracy” us we are on the “geometric open degeneracy” line WMAP3 only best fit LCDM = Ωb + Ωc Assume flatness Reduced 84 LargeLarge ScaleScale StructureStructure && CMBCMB Χρεδιτ Mark Subbarao & SDSS Collaboration 85 SoundSound waveswaves inin thethe earlyearly UniverseUniverse Credit:D.Eisenstein 86 TheThe acousticacoustic peakpeak Credit: D.Eisenstein 87 BaryonBaryon oscillationsoscillations inin LRGLRG galaxiesgalaxies 88 2 DA=DL/(1+z) 89 SNLSSNLS 11--yyrr ++ BAOBAO prior:prior: w=w=--1.021.02±±0.090.09±±0.0540.054 (Astier et al , 2005) 90 GravitationalGravitational leakageleakage intointo XX--dimensiondimension • Use SNLS (Astier et al 2005) + Baryon oscillations (Eisenstein et al 2005) to examine 5D extenction of Friedmann eqn suggested by Dvali, Gabadadge,Porrati 2000; Deffayet, Dvali, Gabadadze 2001. H 8πG H 2 ±= ρ rc 3 Fairbairn & AG, 2005 91 GravitationalGravitational leakageleakage intointo XX--dimensiondimension (2)(2) • Consider more general modifications to Friedmann eqn (as in Dvali & Turner, 2003) H α 8πG Λ equiv H 2 −=ρ 2− α rc 3 Fit SNLS data + baryon oscillations AND flat universe Fairbairn & AG, 2005 92 InvestigatingInvestigating DMDM withwith LSSLSS mν = 0 eV mν = 1 eV Ma ’96 mν = 7 eV mν = 4 eV 94 PerturbationsPerturbations andand powerpower spectraspectra • Gaussian field of density perturbations δ(x) and its Fourier transform δ(k) δ ρρ()xr − ()xr ≡ ; ρ rδδ1 r r ()kxedx= ()r ik⋅ x 3 ; V ∫ r ()xkr δδ== () 0 r 2 Pk()≡ () k δ 95 TheThe powerpower spectrumspectrum 96 LymanLyman--αα ForestForest Neutral hydrogen clouds Credit: N. Wright 97 PowerPower spectrumspectrum andand ΩΩM Increasing the total density of matter (baryons + cold dark matter) pushes the epoch of matter-radiation equality back in time and moves the peak scale (the horizion size at that time) to the right. 98 THE ABSOLUTE VALUES OF NEUTRINO MASSES FROM COSMOLOGY ν m Ω h2 = ∑ ν 93 eV NEUTRINOS AFFECT STRUCTURE FORMATION BECAUSE THEY ARE A SOURCE OF DARK MATTER HOWEVER, eV NEUTRINOS ARE DIFFERENT FROM CDM BECAUSE THEY FREE STREAM −1 dFS ~ 1 Gpc meV SCALES SMALLER THAN dFS DAMPED AWAY, LEADS TO SUPPRESSION OF POWER ON SMALL SCALES 99 NeutrinosNeutrinos asas DMDM candidatescandidates 100 NeutrinosNeutrinos asas DMDM candidatescandidates Credit: M.Tegmark 101 THERE IS A DEGENERACY BETWEEN NEUTRINO MASS AND THE DARK ENERGY EQUATION OF STATE S.Hannestad, ASTRO-PH/0505551 (PRL) 102 USING THE BAO DATA THE BOUND BAO BAO+ IS STRENGTHENED, EVEN FOR VERY GENERAL MODELS LY-α LY-α ∑∑mmνν <<02.48.623 eV eVeV @ @@ 95% 95%95% No BAO 1011 FREE PARAMETERS ν ν ΩΩM ,,ΩΩBB,,Hw0,,Hn,0τ,,nA,,τb,,Am,b, ,Nmν ,Q, N,αν s WMAP, BOOMERANG, CBI SDSS, 2dF SNLS SNI-A,SNI-A SDSS BARYONS GOOBAR, HANNESTAD, MÖRTSELL, TU (astro-ph/0602155, JCAP) WITH THE INCLUSION OF LYMAN-ALPHA DATA THE BOUND STRENGTHENS TO m < 0.2 − 0.45 eV @ 95% ∑ ν 103 AssumptionsAssumptions && ResultsResults 104 NewNew excitingexciting SNSN datadata--setssets SDSSSDSS II:II: intermediateintermediate--zz SNeSNe • Three year project started in September 2005. • Aiming at filling in the ”gap” left by eg SNLS and ESSENCE with 200 well measured, accurately calibrated, multicolor LCs 106 SDSSSDSS--IIII SNeSNe fromfrom 20052005 107 ResultsResults fromfrom 20052005 • 126 spectroscopically confirmed SN Ia ( Χ SDSS SNLS 109 AsAs ofof todaytoday ~noon~noon 110 TheThe highesthighest redshiftsredshifts Working at z>1 FindingFinding SupernovaeSupernovae withwith HSTHST 112 VeryVery--highhigh ZZ supernovaesupernovae fromfrom ACS/HSTACS/HST (Riess et al 2004) •By now >40 SNe discovered from space, up to z=1.7 •Reported CL-regions due to statistical errors 113 SNSN 1997ff1997ff aa SNSN atat zz==1.71.7 114 SeenSeen thethe transition?transition? 115 CouldCould gravitationalgravitational lensinglensing affectaffect thethe SNSN resultsresults?? ””BlurringBlurring”” ofof standardstandard candlecandle duedue toto gravitationalgravitational lensinglensing (Bergström, Goobar, Goliath, Mörtsell) • SN light (de)magnified by inhomogeneous foreground matter • The error increases with redshift • Different lensing models — Smooth halo models — Admixture of compact objects? 117 LensingLensing ((de)magnificationde)magnification inin thethe GOODSGOODS SNSN surveysurvey:: aa studystudy casecase • The photometric redshift catalogue for GOODS used to study the line- of-sight properties of the SNIa in the Riess et al 2004 sample (see Gunnarsson et al ApJ 2006 and Jönsson et al ApJ 2006) • Faber-Jackson & Tully Fischer relations used for M/L • Galaxy halos modelled as truncated SIS or NFW • Self-consistency loop: mass density in galaxies + unresolved matter=ΩM 118 MagnificationMagnification probabilityprobability • We find evidence for magnified and z=1.27 demagnified supernovae (µ≠1) • Uncertainty computed by error progation from: ¾ Finite field size error ¾ Redshift and position errors ¾ Scatter in FJ&TF relations ¾ Survey magnitude limit (incompleteness) PDF built up by randomizing the contributions above according to their individual uncertainties, z=1.75 • Estimate of magnification in SN1997ff smaller than in Benitez et al 2002, Riess et al 2004. This is understood, both authors now agree with our result. 119 LensingLensing PDFsPDFs forfor GOODSGOODS SNSN--samplesample We found NO evidence for selection effects due to lensing in the GOODS SN sample.Negligible corrections to Ω’s & w. Expected lensing bias on SNLS results is also small: |δΩM| ~0.01 in ΩM-ΩΛ plane. Added uncertainty on w0 is σw~0.014 for BAO prior (SNOC simulation) 120 CosmologicalCosmological parametersparameters • We found NO evidence for selection effects due to lensing in the GOODS SN sample. • Lensing distributions compatible with simulations, e.g SNOC. • JDEM: statistical uncertainty due to weak lening can be reduce by about Only GOODS SNe corrected for lensing 50% by including l-o-s galaxy (and LSS) information measured with same instrument. • Possible lensing bias on SNLS results is small: |δΩM| ~0.01 in ΩM-ΩΛ plane. Added uncertainty on w0 (after prior on baryon oscillations) is σw~0.014 121 DownloadDownload:: www.physto.sewww.physto.se/~ariel/~ariel MC + cosmology fitting code specifically developed to understand science reach and systematic uncertainties in observations of high-z SNe, e.g. due to intervening dust gravitational lensing, search biases, non-SNIa contamination, etc. A.G et al (2002) Astronomy & Astrophysics, 392,757 122 WhatWhat aboutabout dustdust oror somethingsomething elseelse attenuatingattenuating thethe signal?signal? Dust/Dust/reddeningreddening:: aa realreal problem!problem! B-V color • Dust in SN host galaxy (or along line of of low-z SNe sight) • Correction assumes some reddening law, typically Galactic type dust (SCP,High-Z Team) or average fit to any kind of reddening/blueing (SNLS) • Can only be estimated for individual SNe with Extinction: a) accurate multi-wavelength data b) good knowledge of intrinsic ”color” ∆MB=RB·E(B-V) with RB~ 2 - 5 of SNe • Extinction probabilty in a given galaxy Extinction correction dominates depends on where the SN explosion happens measurement error! Exception: Elliptical galaxies (E/S0) have little star-formation & dust. 124 MilkyMilky WayWay dustdust • Wavelength dependence parametrized by Rv, • Av= Rv E(B-V) • Average value Rv=3.1 -4 • Rv ~1 → Rayleigh scattering , Aλ=kλ • Rv »3 → “Gray” dust, weak wavelength dependence (especially in UV and optical) Cardelli, Clayton & Mathis, 1989 125 SystematicSystematic effectseffects No extinction correction. Reddened SNe excluded With extinction correction Largest source of identified syst in Knop et al 126 ExtinctionExtinction//reddeningreddening correctionscorrections Riess et al 2004 (gold sample) Latest news: non-linearity in • z-dependence in reported Av ? ? • Problems with K-corrections/assumed NICMOS detector requires intrinsic colors in UV part of the ~0.2 mag corrections that seem SNIa spectrum? to explain this!!! • Changing dust properties ? ∆Μ∆ • Selection effects? ΜV • Degeneracy in global fit? • Watch out for priors on A ! Riess et al Β V assume P(Av)~exp(-Av) • Potential inconsistency for elliptical hosts SN97ff: assumed extinction- Uncertainties ? free, E-host 127 SNSN cosmologycosmology atat longerlonger wavelengthswavelengths?? • Use restframe I-band lightcurves to check cosmological results: different systematics! (S.Nobili, PhD thesis, Nobili et al 2005) 128 ””DustfreeDustfree andand decelerateddecelerated”” Sullivan et al 2003 • 219 HST/ACS Orbits awarded (PI: Perlmutter) in galaxy type dispersion C14 for rolling search for SNe on galaxy clusters 0.9 Cluster RCS0221-03 at z = 1.02 Host was cataloged Cluster member. Spectrum taken for confirmation. preliminary ACS z band ACS I band Nicmos J band 130 ACSACS isis backback afterafter aa glitchglitch thisthis summer!summer! 131 DustDust betweenbetween galaxiesgalaxies?? Grey intergalactic dust GreyGrey IGIG dustdust AG,Bergström & Mörtsell, A&A, 2002 • Large dust grains (weak wavelength dependence) may exist in the IG- Model A medium Concordance • Evolution of dust density: two limiting cases: Milne 3 ModelB; 1. ρdustα (1+z) [Model A] ΩM=1 3 2. ρdustα (1+z) for z<0.5 & ρdust(z>0.5)= ρdust(z=0.5) [Model B] • Hard to rule out from SN-colors (c.f Nobili et al) • X-ray point-sources at very high-z, (e.g. Petric et al) do not exclude e.g Model B • SDSS QSO colors (>16000 objects, IG Dust cannot explain observed z<2) <0.1 mag extinction for SN1a at faintness of SNe – but is a serious z=1; faintness of SNe cannot be only concerndue to IG-dust for precision cosmology Mörtsell & AG, 2003, 133 Östman & Mörtsell, 2005 WhatWhat improvementimprovement inin understandingunderstanding ofof darkdark energyenergy cancan bebe expectedexpected inin nearnear futurefuture fromfrom SNIaSNIa?? WhatWhat toto expectexpect fromfrom onon--goinggoing effortsefforts?? • Data-sets in the making: SNLS ~ 700 SNe (+ ESSENCE) SDSS- II ~ 200 SNe low-z ~ 100 SNe very high-z ~ 100 SNe ”combo” ------Total 1200 SNe • Simulate a ”combo” data-set using the same z-distributions as today, just scale up numbers • Neglect systematics – to begin with! today 135 ””ComboCombo”” MCMC datadata--setset:: w/ow/o systematicssystematics Sne + flat BAO prior Current SNLS Current BAO 136 ””ComboCombo”” MCMC datadata--setset:: w/ow/o systematicssystematics SNLS Sne + flat BAO prior Combo Current SNLS Current BAO 137 HostHost galaxygalaxy extinctionextinction systematicssystematics Bias if no correction added 138 PlanckPlanck satellitesatellite • Next European lead CMB mission • Launch ¾ of 2008 • Significantely better S/N compared with WMAP • Better angular sensitivity • Good polarization capability 139 ΩΩGW::GravityGravity waveswaves affectaffect mapsmaps ofof polarizedpolarized radiationradiation 140 WMAPWMAP vsvs PlanckPlanck 141 WMAPWMAP vsvs PlanckPlanck 142 ””WishWish listlist”” forfor futurefuture SNSN projectsprojects • Large statistics – also to constrain systematics: compare ”like to like” • Ideally, build entire Hubble diagram with e.g. only SNe on ellipticals (less dust) • Multi-wavelength coverage (UV-NIR): 1) cover wider range of redshift 2) fit extinction law in host and line-of- sight 3) Find optimal match – minize K-correction uncertainty 4) Accurate photometric redshifts • Spectroscopic capability: hope to find a second parameter that sharpens the ”standarizable” candle, or else it seems unfeasible to reach below σ <0.2 w1 with current techniques. • Instrument should allow a varity of complementary techniques: weak- lensing, baryon oscillations, cluster counting, strong lensing, other candles like Type II Sne, etc. 143 ProjectsProjects forfor thethe nextnext 55--1010 yearsyears?? • Pan-STARRS, four 1.8-m telescopes, each with a 3 degrees FOV. First unit in June 06 in Haleakala on Maui (Hawaii); Full operations by 2010? • Dark Energy Camera: a new 2.2 deg. FOV optical CCD camera on the 4-m telescope at CTIO, Chile. Instrument R&D and Construction 2005-2009. Survey 2009-2014(?) 144 ””BigBig”” FutureFuture ProjectsProjects • LSST: 8-meter class telescope with 10 sq.degrees FOV • JDEM: satellite mission:~2-meter class telescope reaching NIR. Either optical+NIR imaging + spectrosocopy (SNAP) or NIR optical+spectrsocopy (JEDI) NIR grism (DESTINY) • It’s all about minimizing the systematics and (hopefully!) sharpen the standard candle by comparing ”like to like” • Time scales ~10 years from now! Exact time for JDEM unknown but highest priority among ”Beyond Einstein Probes” 145 146 SNAP:SNAP: probingprobing DarkDark EnergyEnergy modelsmodels 147 SNAPSNAP precisionprecision onon ww’’ Frieman, Huterer, Linder, Turner 2002 148 WhyWhy inin spacespace?? 149 Atmospheric emission spectum 150 SNeSNe ++ WeakWeak LensingLensing Bernstein, Huterer, Linder, & Takada √ • Comprehensive: no external priors required! • Independent test of flatness to 1-2% • Complementary: w0 to 5%, w′ to 0.11 (with systematics) +baryon oscillations? SNAP:SNAP: otherother GLGL sciencescience potentialspotentials • Independent measurement of H0,ΩM,ΩΛ,w from time delay of multiply imaged supernovae, mainly Type II (AG, Mörtsell, Amannulah & Nugent). 2 ∆θ DDl s ∆=tzfr1(); + ()l flux 2 Dls DDzzH=ΩΩ(, ; , , , w ) ij ij ij 0 MXx The Refsdal method 152 Strong lensing science potential: 3 year run, optical + NIR 20 º SNIa H0 exactly known A.G, Mörtsell, Amanullah & Nugent, 2002 153 SNAPSNAP –– TheThe moviemovie 154 155