Fondo Cosmico di Microonde: implicazioni delle moderne osservazioni, prospettive future Carlo Baccigalupi SISSA, Trieste Societa’ Italiana di Fisica Italiana September 23°, 2013
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Fondo Cosmico di Microonde: implicazioni delle moderne osservazioni,
prospettive future Carlo Baccigalupi
SISSA, Trieste Societa’ Italiana di Fisica Italiana
September 23°, 2013
Outline
• CMB anisotropies in the new era:
– Effects from Large Scale Structure make the CMB a Dark Energy Probe
– Searching from Cosmological Gravitational Waves
• The status of observations as set by Planck
• Latest discoveries and future directions
CMB anisotropies
CMB: where and when?
• Opacity: λ = (neσT)-1 « horizon
• Decoupling: λ ≈ horizon
• Free streaming: λ » horizon
• Cosmological expansion, Thomson cross section and electron abundance conspire to activate decoupling about 380000 years after the Big Bang, at about 3000 K CMB photon temperature
A postcard from the big bang
• From the Stephan Boltzmann law, regions at high temperature should carry high density
• The latter is activated by perturbations which are intrinsic of the fluid as well as of spacetime
• Thus, the maps of the CMB temperature is a kind of snapshot of primordial cosmological perturbations
CMB physics: Boltzmann equation
d photons
= gravity + Compton scattering
dt
d baryons+leptons
= gravity + Compton scattering
dt
CMB physics: Boltzmann equation
d neutrinos = gravity + weak interaction dt
d dark matter = gravity + weak interaction (?) dt
gravity = photons + neutrinos + baryons + leptons + dark matter
CMB physics: gravity
CMB Physics: Compton scattering
• Compton scattering is anisotropic
• An anisotropic incident intensity determines a linear polarization in the outgoing radiation
• At decoupling that happens due to the finite width of last scattering and the cosmological local quadrupole
e-
CMB anisotropy: total intensity
+
+
CMB anisotropy: polarization
+
+
+
Gradient (E):
Curl (B):
Last scattering
Forming structures
LSS effects on CMB
? ?
?
? ?
? ? ?
Categories for LSS effects on CMB
• Re-scattering
• Gravitation
Categories for LSS effects on CMB
• Re-scattering
– Re-ionization
• Gravitation
– Time evolution of the metric tensor
– Deflection
CMB anisotropy: reionization
e-
e-
e-
Last scattering
Forming structures
Integrated Sachs-Wolfe
Sachs & Wolfe 1967
Last scattering
Forming structures
Integrated Sachs-Wolfe
Sachs & Wolfe 1967
Last scattering
Forming structures
Integrated Sachs-Wolfe
Sachs & Wolfe 1967
Last scattering
Forming structures
Integrated Sachs-Wolfe
Sachs & Wolfe 1967
H-1
Last scattering
Forming structures
Integrated Sachs-Wolfe
Sachs & Wolfe 1967
Last scattering
Forming structures - lenses
CMB lensing
Bartelmann, Schneider 2001, Hu 2000
T
Forming structures - lenses
E B
CMB lensing
Last scattering
Kamionkowski, Kosowsky & Stebbins, Zaldarriaga & Seljak1998
T Forming structures - lenses
E B
CMB lensing
acceleration
Last scattering
z
Energ
y d
ensity
104 0.5
dark energy
The promise of CMB lensing
z
Ener
gy d
en
sity
104 0.5
dark energy
The promise of CMB lensing
Dark energy matter equivalence
CMB last scattering
Matter radiation equivalence
103
Dark energy domination
z
Ener
gy d
en
sity
104 0.5
dark energy
The promise of CMB lensing
Dark energy matter equivalence
CMB last scattering
Matter radiation equivalence
103
Dark energy domination
Stru
ctu
re f
orm
atio
n
z
Energ
y d
ensity
104 0.5
dark energy
The promise of CMB lensing
z
Energ
y d
ensity
0.5
The promise of CMB lensing
1 1.5
z
Energ
y d
ensity
0.5
The promise of CMB lensing
dark energy
The promise of CMB lensing
• By geometry, the lensing cross section is non-zero at intermediate distances between source and observer
• In the case of CMB as a source, the lensing power peaks at about z=1
• Any lensing power in CMB anisotropy must be quite sensitive to the expansion rate at the onset of acceleration
Lensin
g p
robabili
ty
z 1
z
Energ
y d
ensity
0.5
The promise of CMB lensing
Le
nsin
g p
rob
ab
ility
1 1.5
z
Ener
gy d
en
sity
0.5
Lensing strength recording the cosmic density at the onset of acceleration
Len
sin
g p
rob
abili
ty
1 1.5
Cosmological constant
z
Ener
gy d
en
sity
0.5
Lensing strength recording the cosmic density at the onset of acceleration
Len
sin
g p
rob
abili
ty
1 1.5
Cosmological constant
dark energy
Anisotropies
T(θ,φ), Q(θ,φ), U(θ,φ), V(θ,φ)
X=T,E,B
X(θ,φ)=Σlm almX Ys
lm(θ,φ)
spherical
harmonics
s=0 for T, 2 for Q and U
E and B modes have opposite parity
Angular power spectrum
T(θ,φ), Q(θ,φ), U(θ,φ), V(θ,φ)
aXlm, X=T,E,B
Cl=Σm [(almX)(alm
Y)*]/(2l+1)
spherical
harmonics
information
compression
CMB angular power spectrum
Angle ≈ 200/l degrees
CMB angular power spectrum
Angle ≈ 200/l degrees
Primordial power
Gravitational waves
Acoustic oscillations
CMB angular power spectrum
Angle ≈ 200/l degrees
Primordial power
Gravitational waves
Acoustic oscillations
Reionization
Lensing
ISW
The status of observations as set by Planck
Planck
• Hardware: ~600 ME, third generation CMB probe, ESA medium size mission, NASA (JPL, Pasadena) contribution on cooling systems
• Low Frequency Instrument (LFI, Nazareno Mandolesi PI, instrument design and construction supervised by Marco Bersanelli) based on radiometer technology operating at three frequency channels, 30, 44, 70 GHz
• High Frequency Instrument (HFI, Jean-Loup Puget PI) based on bolometer technology, operating at 100, 143, 217, 353, 545 GHz
• About 16 years (1993-2009) of design and construction
The Planck focal plane
Planck detectors
Planck frequency coverage
The Planck launch, May 14th, 2009
Planck milestones
• May 14th, 2009, launch, the High Frequency Instrument (HFI, bolometers) is on
• June 1st, 2009, active cryogenic systems are turned on
• June 8th, 2009, the Low Frequency Instrument (LFI, radiometers), is turned on
• Summer 2009, Planck gets to L2, survey begins, 14 months
• 2 years of proprietary period and data analysis
• Mission extended! High frequency observations ended in early 2013, Low frequency observations ended this summer
• Early papers on extra-Galactic astrophysics, 2011
• Intermediate papers on extra-Galactic and Galactic astrophysics, 2012
• More astrophysics and first Cosmological Results based on total intensity, 2013
• Astrophysics and Cosmology results based on total intensity and polarization expected in 2014
Data flow and analysis levels
• Level 1, telemetry, timeline processing, calibration
• Level 2, map-making
• Level 3, multi-frequency analysis, production of Galactic, extra-Galactic and CMB science products
Mission Operation Center, Darmstadt
Trieste LFI timeline processing and map-making
Paris HFI timeline processing and map-making
Map exchange, separation of astrophysical foreground and backgrounds, Galactic, extra-Galactic astrophysics, CMB science
Planck contributors
Davies
Berkeley
Pasadena Rome
Helsinki
Copenhagen Brighton
Oviedo
Santander Padua
Bologna
Trieste Milan
Paris Toulouse
Oxford
Cambridge Munich
Heidelberg
Bucarest
Planck data processing sites
Trieste Paris
A Dark Universe
53
The birth of Cosmic Structures I
• The Planck is the first single experiment mapping the Earliest cosmological structures from a few million to tens of billions light years
• The Statistical Distribution Spots on the CMB map tells us about the process which imprinted them, likely a short period of accelerated expansion, the Inflation, immediately after the Big Bang
• According to Planck, spots with smaller sizes are fainter than the ones which larger size, indicating a dynamics and an actual «end» of the Inflation
54
The birth of Cosmic Structures II
• The Planck capability of imaging the early Universe is unprecedented
• The Statistical Distribution Spots on the CMB map tells us about the process which imprinted them, likely a short period of accelerated expansion, the Inflation, immediately after the Big Bang
• According to Planck, spots follow the Gauss distribution, which means no «order» is detected in the generation of Cosmological Perturbations
• Ripercussions of this discovery are ongoing
55
Dark Lenses bending Light
56
The Dark Lenses as seen by Planck
57
Planck reveals Cosmic Light Bending
58
Early dark energy and CMB lensing
Acquaviva & Baccigalupi 2006
CMBreaking projection degeneracy
Acquaviva & Baccigalupi 2006
CMB lensing detection
Keisler et al. 2011
CMBroken degeneracy
Sherwin et al. 2011
CMBroken degeneracy
Van Engelen et al. 2012
Planck XV, 2013
A few questions…
Carlo Baccigalupi « Cosmology from Planck 2013"
65
• Can we know more about the Inflation?
• Can we know more about the Dark Cosmological Components?
• Are there challenges to the basic cosmological principles?
• What Planck and Cosmology can tell us in the near future?
Latest discoveries and future directions
The first evidence of lensing B modes
Hanson et al. 2013
The first evidence of lensing B modes
Hanson et al. 2013
Future directions
69
• Near future
– Sub-orbital experiments targeting lensing B modes
– Gradually extending fields to search for gravitational waves on the degree scale
• Far future
– The extreme early Universe: proposals for future CMB satellites
– Pushing CMB-LSS cross-correlation to its limits: Euclid
Upper bounds on B modes
Bischoff et al. 2011
B modes hunters
• See lambda.gsfc.nasa.gov for a full list of operation or planned experiments
• Forecasted performance from – LSPE
– EBEX
– PolarBear
COsmic oRigin Explorer
White paper: arxiv.org/abs/1102.2181
PRISM
White Paper arxiv.org/abs/1306.2259
Satellites: Euclid, to fly in 2020
74
Next ESA selected Cosmology Satellite Mission Designed to study Dark Energy and Matter in Cosmological Structures
See the Euclid groups at ICTP, INAF-OATs, SISSA, UniTs. sci.esa.int/euclid
Concluding remarks
• Present and future lines for CMB exploitation: – Effects from the LSS for investigating the dark components – The extreme early Universe through the quest for
detecting Cosmological Gravitational Waves
• Intense observation campaigns are being carried out from sub-orbital probes as well as satellites, for both lines
• LSS effects have been detected, and being used to constrain the Dark Cosmological Components
• B modes from gravitational lensing have been detected • The quest for B modes from Cosmological Gravitational
Waves is in progress
Concluding remarks: Planck
76
• Planck confirms the existence of Dark Energy and Matter • Bending of Light as seen by Planck reveals Dark Lenses acting in the same epoch of the
accelerated cosmic expansion • Gravitational waves, if existing, are less than 10% of the density perturbations • Sum of mass of neutrino is less than 0.2 eV • The Dark Energy is a Cosmological Constant, within errors • Planck reveals that the «transient» energy driving inflation was actually dynamic, and
«decreasing» in time • Planck sees no «order» in the process which generated cosmological perturbations • Data Analysis still ongoing, published data concern less than half of the mission • 2014: Planck increases accuracy on the above results • 2014: Planck publishes polarization data, along with constraints on Cosmological
Gravitational Waves from large scales • 2014-2016: results from sub-orbitals came on-line with constraints on Cosmological
Gravitational Waves from the degree angular scale • Beyond: studies of cross-correlation of Planck CMB and Large Scale Structure make
progresses, heading to the next Cosmology ESA Satellite • Beyond: post-Planck CMB polarisation satellite
The scientific results that we present today are a product of the Planck Collaboration, including individuals from more than 100 scientific institutes in Europe, the USA and Canada
Planck is a project of the European Space Agency, with instruments provided by two scientific Consortia funded by ESA member states (in particular the lead countries: France and Italy) with contributions from NASA (USA), and telescope
reflectors provided in a collaboration between ESA and a scientific Consortium led and funded by Denmark.
CITA – ICAT
UNIVERSITÀ DEGLI STUDI
DI MILANO
ABabcdfghiejkl
Carlo Baccigalupi « Cosmology from Planck 2013"
77
Backup slides
Carlo Baccigalupi SISSA, Trieste
On behalf of the Planck collaboration
Trieste, time ordered data processing,
Component separation, cosmological parameters
Rome, GLS map-making, power spectra,
cosmological parameters
Bologna, beam reconstruction,
power spectra,
cosmological parameters
The LFI DPC
Helsinki, destriper map-making
Milano, calibration,
component separation
Berkeley, simulations
Padova, component separation
The Planck Data Processing Centre
Carlo Baccigalupi « Cosmology from Planck 2013"
80
A mini-Dark Energy course
Fighting the cosmological constant
Gµν=8πTµν
Fighting the cosmological constant
Gµν+Λg µν=8πTµν +Vgµν
geometry
quantum vacuum
Fighting the cosmological constant
Λ:???
Fighting the cosmological constant
Λ:???
V:M4Planck
???
Fighting the cosmological constant
Λ:???
V:M4Planck
???
|Λ-V|/M4Planck≲10
-123
Fighting the cosmological constant
Λ:???
V:M4Planck
???
|Λ-V|/M4Planck=10-123
percent precision
(Boh?)2
• Why so small with respect to any other known energy scale in physics?
• Why comparable to the matter energy density today?
z
Ener
gy d
en
sity
104 0.5
dark energy
Dark Energy
z
Ener
gy d
en
sity
104 0.5
cosmological constant
Dark Energy
Einstein 1916
z
Ener
gy d
en
sity
104 0.5
tracking quintessence
Dark Energy
Ratra & Peebles, 1988
z
Ener
gy d
en
sity
104 0.5
early quintessence
Dark Energy
Wetterich 1988
z
Ener
gy d
en
sity
104 0.5
Dark Energy
z
Ener
gy d
en
sity
104 0.5
dark energy
Parametrizing cosmic acceleration is …
ρ(z)
z
Ener
gy d
en
sity
104 0.5
…parametrizing cosmic density
ρ∝(1+z)3[1+w]
constant w
z
Ener
gy d
en
sity
104 0.5
Parametrizing cosmic density
ρ∝exp{3∫0z [1+w(z)]dz/(1+z)}
variable w
a=1/(1+z)
w
0.5 1
w=w0-wa(1-a)=w0+(1-a)(w∞-w0)
-1
w0
w∞
Chevallier & Polarski 2001, Linder 2003
Constraining Dark Energy: models
a=1/(1+z)
w
0.5 1
-1
Crittenden & Pogosian 2006, Dick et al. 2006,Said et al. 2013
Constraining Dark Energy: binning
Constraining Dark Energy: latest pre-Planck constraints
Said et al. 2013
Cosmological expansion and CMB: projection
D= H0-1
dz
[ΣiΩi(1+z)3(1+wi)]1/2 ∫ 0
z
w D
Cosmological expansion and CMB: Integrated Sachs-Wolfe
Cosmological friction for cosmological perturbations∝H
w ρ H
Integrated Sachs-Wolfe
Cosmological friction for cosmological perturbations∝H
w ρ H
Cross-correlating with LSS
Cross-correlating with LSS
Perturbation statistics and dynamics → early Universe
Cross-correlating with LSS
Geometry and perturbation dynamics → dark energy effects
ISW-LSS correlation detection
Fosalba, Gaztagnaga 2003 Padmanabhan et al. 2005
ISW-LSS impact on cosmology
Xia et al. 2010 Giannantonio et al. 2008
Planck XIX, 2013
Planck XIX, 2013
CMB lensing
Acquaviva et al. 2004
CMB lensing
Geometry Acquaviva et al. 2004
CMB lensing
Perturbation dynamics Acquaviva et al. 2004
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