Cosmology and AstroparticlePhysics

¬ Introduction

­ Dark Matter Searches

® High Energy Astronomy

(mostly taken from J. Carr’s lectures for summer students at CERN)

What is Astroparticle Physics ?

ParticlePhysics Astronomy

Astrophysicsand cosmology

PARTICLE

ASTROPHYSICS

Particle Astrophysics/ Nuclear Astrophysics

Use input from Particle Physics to explain universe: Big Bang, Dark Matter, ….

Use techniques from Particle Physics to advance Astronomy

Use particles from outer space to advance particle physics

Astronomy Scales

4.5 pc 450 kpc 150 Mpc

Nearest Stars Nearest Galaxies Nearest Galaxy Clusters

1 pc= 3 light years

Milky Way Galaxy

Magnetic field∼ few µG

Galactic Co-ordinate System

+180°−180°

+90°

−90°

What do we know about the Universe ?

• Many things, including the facts that…– It expands– Particles are coming on Earth at energies 108 times larger

than we are able to produce…

1920: Edwin Hubble e l’espansione dell’Universo

• Hubble osservo’ che le galassie si allontanano da noi con una semplice relazione tra distanza e velocita’ di allontanamento

Redshift

Legge di Hubble

Pendenza = Ho (costante di Hubble)

Oggi: H0 = 72 ± 8 km/s/Mpc

Aspetti della legge di Hubble

• Ogni punto recede da ogni altro punto (ogni punto sembra essere al centro di un Universo in espansione)

• Piu’ lontano e’ un punto e piu’ velocemente si allontana– La relazione e’ lineare: doppia distanza, doppia velocita’

• L’oggetto sembra piu’ “rosso” (effetto Doppler)

Viaggio nel tempo passato...L’Universo una volta era piu’ piccolo

Singolarita’

primordiale !!!

=> BIG BANG

E “prima” ancora ?

• Interrelazione spazio-tempo-movimento: Aristotele, FisicaNON CITO: il concetto di tempo è legato a quello di movimento, spazio, cambiamento. Il tempo determina il movimento, essendo la misura di esso, ma il movimento determina a sua volta il tempo, poiché il tempo è dovuto alla percezione di una relazione d'ordine relativa al movimento.

Quanto indietro nel tempo ?• Estrapolando la velocita’ attuale di espansione

indietro al Big Bang

T = 1/H0 ~ 15 miliardi di anni

• Consistente con l’eta’ delle stelle piu’ vecchie

Tempo e temperatura• L’Universo una volta era piu’ caldo

– L’espansione richiede lavoro contro la gravita’– La temperatura e’ proporzionale all’energia cinetica

media

n Si pensi all’espansione del gas contenuto in un accendino

915~ 10T K

t

Disaccoppiamento• Fotoni γ ↔ Particelle + Antiparticelle

(finche’ l’energia dei fotoni e’ sufficiente)

γ ↔ protone-antiprotoneγ ↔ elettrone-antielettrone

(…)dopodiche’ la materia diviene stabile

Tem

po

Due epoche

Particle Physics after Big Bang

time since Big Bang

charged particles protonsionselectrons

neutral particles photonsneutrinos

at ground level :~ 1/s/m²

Primary cosmic raysproduce showers in high atmosphere

Primary: p 80 %, α 9 %, n 8 %e 2 %, heavy nuclei 1 %γ 0.1 %, ν 0.1 % ?

Secondary at ground level: ν 68 %µ 30 %p, n, ... 2 %100 years after discovery by Hess origin still uncertain

Cosmic Rays

Particle Acceleration

R ∼ 1015km, B ∼ 10−10T ⇒ E ∼ 1000 TeV

R ∼ 10 km, B ∼ 10 T ⇒ E ∼ 10 TeV

Large Hadron Collider

Tycho SuperNova Remnant

E ∝ BR

( NB. E ∝ Z → Pb/Fe higher energy)

Energy of accelerated particles

Dia

met

er o

fcol

lider

Cyclotron Berkeley 1937

Particle Physics ⇒ Particle Astrophysics

LHC CERN, Geneva, 2007

Terrestrial Accelerators Cosmic Accelerators

Active Galactic Nuclei

Binary Systems

SuperNovaRemnant

Ultra High Energy from Cosmic Rays

1 102 104 106 108 1010 1012

Energy GeV1 102 104 106 108 1010 1012

Energy GeV

cros

s-se

ctio

n (m

b)

part

icle

flux

/m2 /s

t/sec

/GeV

From laboratory accelerators From cosmic accelerators

FNAL LHC FNAL LHC

Flux of cosmic ray particlesarriving on Earth

Particle cross-sections measured in accelerator experiments

Ultra High Energy Particles arrive from space for free: make use of them

CollidersColliders

Fixed targetbeamlines

Multi Messenger Astronomy

Télescope radio (Bonn) Télescope optique (Palomar, USA) Satellite Rayon X (INTEGRAL, Europe) Télescope gamma (CAT, France)

1 0 - 5 1 0 -4 1 0 -3 1 0 - 2 1 0 -1 1 1 0 1 0 2 1 0 3 1 0 4 1 0 5 1 0 6 1 0 7 1 0 8 1 0 9 1 0 1 0 1 0 1 1 1 0 1 2 1 0 1 3 1 0 1 4 1 0 1 5 e Vm c m m m µ m n m Å

O p t i q u eR a d i o I n f r a r o u g e R a y o n s G a m m aR a y o n s X

Radio Lumière visible Rayon X Rayon gamma

Visualisations du ciel (repère galactique) avec lumières en quatre longueurs d’onde différentes

View of sky in Galactic Coordinates in four different photon wavelengths

Radio Visible light X - rays γ rays

Radio Telescope Optical Telescope X - ray Satellite γ - ray Telescope ( Bonn) (Palomar) (INTEGRAL/ESA) ( CAT Pyrenees)

Radio 408 Mhz

Infrared 1-3 µm

Visible Light

Gamma Rays

Centre of Galaxy in Different Photon Wavelengths

absorption cut-off mean free pathγ-rays: γ + γ2.7k >1014eV 10 Mpcproton: p + γ2.7k→ π0 + X >5.1019eV 50 Mpcnuclei: photo-disintegration >5.1019eV 50 Mpcneutrinos: ν + ν1.95K → Z+X >4.1022eV (40 Gpc)

magnetic deflection∆θ(rad)= L(kpc) Z B(µG)/E(EeV) Galaxy B=2µG, Z=1, L=1kpc -> ∆θ =12deg at 1019eV

Photons absorbed on dust and radiation

Protons deviated by magnetic fields

Neutrinos direct

Multi-Messanger Astronomy

Multi-Messengers to see Whole Universe

Distant universeinvisible in high energy photons

need neutrinos

Quasarformationperiod

Surprises in History of AstronomyNew astronomic instruments often give unexpected results:

With future new detector can again hope for completely new discoveries

Telescope User date Intended Use Actual use

Optical Galileo 1608 Navigation Moons of Jupiter

Optical Hubble 1929 Nebulae ExpandingUniverse

Radio Jansky 1932 Noise Radio galaxies

Micro-wave Penzias,Wilson 1965 Radio-galaxies, noise 3K cosmic

background

X-ray Giacconi … 1965 Sun, moon neutron stars

accreatingbinaires

Radio Hewish,Bell 1967 Ionosphere Pulsars

γ-rays military 1960? Thermonuclearexplosions

Gamma raybursts

neutrino

Evidence for Matter Density- Galaxy Dynamics- Strong Gravitational Lensing- SN Ia- Cosmic Microwave Background Radiation

Searches- Astronomy Dark Matter Candidates (Baryonic)

- Particle Dark Matter CandidatesNeutrinosWIMPs: Direct and Indirect Searches

Dark Matter Searches

Galaxy Rotation

Gravity:G M(r) / r2 = v2 / renclosed mass: M(r) = v2 r / G

velocity, vradius, r

Luminous stars only small fraction of mass of galaxy

Mass in a typical galaxyRotation curve Mass from rotation curve

Density

halo

disk

bulgeDark matter

in halo

but detailed distribution?

CandidatesM > ~ 40 GeV if SUSY (LEP)

Neutrino Mass

ν νν

νννν ν

Atmospheric Neutrino Oscillations:disappearance of νµ

Pdis = sin22θ sin2(1.27 ∆m2L/E), ∆m mass difference, θ mixing angle E energy of ν, L oscillation length

Data from SuperKamiokande

M( νµ) − M( ντ) ∼ 0.05 eV

( M( νe) − M( νµ) < 0.01 eV Solar Neutrinos)

Gravitational Lensing by Dark Matter

Hubble Space Telescopemultiple imagesof blue galaxy

Reconstructed matter distribution

Magellanic Clouds

Halo of DarkBrown Dwarfs?

Lines of view

GalaxyEarth

Gravitational Lensing Searches for MACHOs

~ 200 km/s

Dark Halo ObjectBright star in

Magellanic CloudTelescopeon Earth

t

A

Gravitational Microlensing

Large Magellanic Cloud

Two colours to eliminate variable stars

SupernovaeImplosiondu noyaud ’étoile

Explosion d ’étoile

Expansion du matière onde de choc ⇒ accélération

Supernova Restes du Supernova

Implosion of core ofred giant

Expansion of mattershock wave ∼ 0.5 c

Explosion of star

Supernova Supernova Remnant

SNIa occurs at Chandrasekar mass, 1.4 Msun ⇒ ‘Standard Candle’

measure brightness → distance: B = L / 4πd2

measure host galaxy redshift → get recession velocity

test Hubble’s Law: v = H d, at large distances

Expansion with Supernovae Ia

Acceleration ofuniverse expansion

effe

ctiv

e m

agni

tude

→br

ight

ness

→di

stan

ce

non-linear v = H(t) d

redshift → recession velocity

Matter/Energy in the Universe

baryons neutrinos cold dark matter

ΩΜ = Ωb + Ων + ΩCDM ∼ 0.4

Ωtotal = ΩΜ + ΩΛ∼ 1matter dark energy

Baryonic matter :Ωb ∼ 0.05stars, gas, brown dwarfs, white dwarfs

Matter:

Cold Dark Matter :ΩCDM ∼ 0.3

WIMPS/neutralinos, axions

Neutrinos:Ων ∼ 0.003if Μ(ν) ∼ 0.1 eV as from oscillations

WIMP Direct Detection

ER

χχ

~ 10 keV

Elastic interaction on nucleus, typical χ velocity ~ 250 km/s (β ~ 10-3)

Motion of Earth in the χ wind

vsun = 230 km/s

δ = 30o

vorb = 30 km/s

1 2 3 4 5 6 7 8 9 100(E

or/R

o)*d

R(v

E,v

esc)

/dE

RE/(E0r)

0123456789

10

dRdER

= Ro

Eore -ER/Eor

Recoil Spectrum

Featureless recoil energy spectrum ---> looks like electron background

Examples of Direct WIMP Detectors

χχ

χχ

Na I

GeLi

ght a

mpl

itude

Ioni

zatio

n

time

Total energy

signal

signal

background

background

Rejection of background is the critical issue

WIMP Modulation

6

600

~30 kms-1

~220 kms-1Sun

Earth

Jun 2nd

WIMPWIMP

Annual modulationFew percent effect in rate > Ethreshold

(Eor

/Ro)

dR/d

E

E/(Eor)

DAMA - NaI Annual Modulation

• Total 4 years annual modulation - 57986 kg.days• Annual modulation few % of signal• No recoil discrimination

-0.10

-0.05

0.00

0.05

0.10

300 600 900 1200 1500 1800

DAMA Annual Modulation 2-6 keV Bin

ResidualDAMA Fit

Res

idua

l (kg

-1da

y-1ke

V-1

)

Day Number

( INFN/AE-00/01)Evidence for WIMP observation

Energy of accelerated particles

Dia

met

er o

fcol

lider

Cyclotron Berkeley 1937

Particle Physics ⇒ Particle Astrophysics

LHC CERN, Geneva, 2007

Terrestrial Accelerators Cosmic Accelerators

Active Galactic Nuclei

Binary Systems

SuperNovaRemnant

Probing dark matter: WIMPs

Good energy resolution in the few % range is needed

Some dark matter candidates (e.g. SUSY particles) would lead to mono-energetic γ lines through annihilation

X

X

q

qor γγ or Zγ

tracker

ACD

Dd γ

CsIcalorimeter

Types of Cosmic Ray Detectors

Satellites

Array of particle detectors on ground

Whippleγ >1 TeV

Compton Gamma Ray Obs.

EGRET

BATSEγ 0.1-10GeV

KASCADEp,N 0.3-100PeV

KASCADEp,N 0.3-100PeVGround based telescopes

looking at light produced in atmosphere

Arrays of particle detectors

ground level

top ofatmosphere

Ground, Air Shower Arrays

CASA - KASCADE - AGASA - AUGER

Space observedShower

EUSO

Satellite, ballons AMS

Whipple-CAT-HEGRA-CELESTEH.E.S.S.-MAGIC-VERITAS

γ satellite

γ telescopes

ν telescopes

CCGO, GLAST

AMANDA, ANTARES

Charged Cosmic Ray Energy Spectrum

‘knee’

‘ankle’

Whythese

features?

Features of Cosmic Ray SpectrumE

2dN

/dE

[cm

-2s-1

sr-1

eV]

E [ eV/nucleus]

E−2.7

E−3.2

E−2.8ankle

dN/dE ∼ E α + δpro

pagatio

n

source

α = −2.0 to −2.2,..

δ = −0.3 to −0.6

‘Conventional Wisdom’: Galactic SNR

Extragalactic E > 3 1018 eVexotic E > 7 1019 eV

Source acceleration:

Source cut-off eV

GZK cut-off on CMB γ E ≈ 7 1019 eV

Diffusion models

Galactic lossesE < 3 1018 eVE > 4 1014 eV

Ingredients of models:

isotropicMass composition ?

BµGE <1018 Z R

kpcknee

Cosmic Rays Spectrum: Knee and Ankle

Flux × E2.7 Flux × E3

Mass composition from shower depth

1015 1016 1017

1.5

2.5

0.5

3.5

<ln A>

Energy eV

CASA-BLANCA

Flux × E2.5Mean ln(A)

Mass composition at kneeAverage shower depth and ratio Nµ / Ne sensitive to primary mass

(NB. Mass composition extracted is very sensitive to Monte Carlo simulation)

KASCADEKASCADE

KASCADE ⇒ series of knees at different energies: p,He,..,C,..,Fe.E(Knee) ∝ Z ⇒ knee due to source confinement cut-off ?

‘GZK cutoff ’ HE cosmic rays

HE gamma raysMrk 501 120Mpc

Mrk 421 120Mpc

Sources uniformin universe

100 Mpc

10 Mpc

γ γ → e+ e−

p γ → π N

Interaction with background γ( infrared and 2.7K CMBR)

• ‘Bottom-Up’ : acceleration - pulsars in galaxy, - radio lobes of AGN (proximity a problem due to GZK, also should see source)

• ‘Top-Down’ : decay of massive particles - GUT X particles with mass > 1020 eV and long lifetimes - Topological defects- Neutrinos as messenger particle

• New Physics

Explanations of Ankle/ E > 1020 eV events

Particle Physics type explanations

Astronomy type explanations

Water CherenkovTanks

(1600 each 10m2)

Fluorescence Telescopes (6 telescopes each 30° ×30° at 4 sites)

2 sites each 3000km2, E > 5.1018eV

Southern site, Mendoza Province, Argentina

3.5m mirrors

AUGER experiment

AMS

Space Shuttle June 1998

Detailed measurements on Cosmic Ray composition: anti-matter ?

⇒ limit on anti-helium/helium ratio < 10−6

International Space Station 2004

We see only partly what surrounds us

• We see only a narrow band of colors, from red to purple in the rainbow

• Also the colors we don’t see have names familiar to us: we listen to the radio, we heat food in the microwave, we take pictures of our bones through X-rays…

What about the rest ?• What could happen if we would see only, say, green

color?

The universe we don’t see

• When we take a picture we capture light(a telescope image comes as well from visible light)

• In the same way we can map into false colors the image from a “X-ray telescope”

• Elaborating the information is crucial

The high-energy spectrumEγ > 30 keV (λ ~ 0.4 A, ν ~ 7 109 GHz)

Although arbitrary, this limit reflects astrophysical and experimental facts:

• Thermal emission -> nonthermal emission

• Problems to concentrate photons (-> telescopes radically different from larger wavelengths)

• Large background from cosmic particles

Many sources radiate over a wide range of wavelengths

Gamma Ray Astronomy

Energy Spectra of AGN- acceleration process: leptonic or hadronic- GZK cut-off/ background radiation field

Are Supernova Remnants the Source of Cosmic Rays ?

Which sources gives TeV γ, which do not, and why?

Some issues for High Energy Gamma Astronomy:

Low Energy Gamma Astronomy from satellites (EGRET)

E >100 MeV

Transparency of the atmosphere

• Energetic protons and electrons in the vicinity of astrophysical objects might produce gammas

• Synchrotron radiation by electrons in magnetic fields could be boosted to TeV energies by inverse Compton scattering

• If acceleration mechanisms involve hadronic interactions, there are many π0 -> γγ (& the γ give a clear signature)

Acceleration mechanisms and the origin of cosmic rays

Study of exotic objects: Active galaxies

• Many sources, mostly classified according to observational criteria

• Unified AGN model (Begelman et al. 1984): 10% of the accreted mass is transformed into radiation

• Different models predict different γ spectra

But warning : ~300 sources @ the GeV scale, only 15 @ the TeV

Exotic objects: Pulsars• Rapidly rotating neutron stars

with – T between ~1ms and ~1s

– Strong magnetic fields (~100 MT)

– Mass ~ 3 solar masses

– R ~ 10 Km (densest stable object known)

• For the pulsars emitting TeVgammas, such an emission is unpulsed

Crab pulsar

X-ray image (Chandra)

Study of exotic objects: γ-ray bursts (History, I)

• An intriguing puzzle of today’s astronomy… A brief history– Beginning of the ‘60s: Soviets are

ahead in the space war• 1959: USSR sends a satellite to

impact on the moon• 1961: USSR sends in space the 27-

years old Yuri Gagarin

– 1963: the US Air Force launches the 2 Vela satellites to spy if the Soviets are doing nuclear tests in space or on the moon

• Equipped with NaI (Tl) scintillators

Study of exotic objects: γ-ray bursts (History, II)

– 1967 : an anomalous emission of X and γ rays is observed. For a few seconds, it outshines all the γ sources in the Universe put together. Then it disappears completely. Another in 1969...After careful studies (!), origination from Soviet experiments is ruled out

• The bursts don’t come from the vicinity of the Earth

– 1973 (!) : The observation is reported to the world

– Now we have seen hundreds of gamma ray bursts...

Sky coverage in 2002/03

An armada of detectorsat different energy ranges

…some are coming now

MAGIC 2002

GLAST verra’ spedito in orbita nel 2006 da un vettore della NASA. Lo strumento e’ ispirato alle tecniche della fisica delle particelle. Utilizzando un know-how costruito in una pluriennale collaborazione con il CERN di Ginevra e una preziosa sinergia con Informatica, noi Fisici Computazionali di Udine abbiamo la responsabilita’ del software di simulazione e dell’event display e studiamo come interpretare i segnali.

Come ci aspettiamo una mappadel cielo nello spettro dei raggigamma dopo un anno di lavoro di GLAST. Al centro la Via Lattea, la nostra galassia.

A new concept: EUSO (and OWL)

• The Earth atmosphere is the ideal detector for the Extreme Energy Cosmic Rays and the companion Cosmic Neutrinos. The new idea of EUSO (2007-) is to watch the fluorescenceproduced by them from the top

Sensitivity

neutrino

Photons absorbed on dust and radiation

Protons deviated by magnetic fields

Neutrinos direct

In the 100 TeV -100 PeV region…

Neutrino Telescope Projects

NESTOR : Pylos, Greece

ANTARES La-Seyne-sur-Mer, France( NEMO Catania, Italy ) BAIKAL: Lake Baikal, Siberia

DUMAND, Hawaii(cancelled 1995)

AMANDA, South Pole, Antarctica

AMANDASouth Pole: glacial ice

1993 First strings AMANDA A1998 AMANDA B10 ~ 300 Optical Modules

2000 ~ 700 Optical Modules

→ ICECUBE 8000 Optical Modules

AMANDAν > 50GeV

1997 data

... best limits for northern sky ...

319 sky bins

bins

100

10

1

0.1

1 0.1 0.01 0.001

Flux (>10 GeV) < 10-7 cm-2 s-1 @90%

chance probability

1097 events in final sample(75% muons, 25% atmo.ν)319 sky bins

background

equatorial coordinates

24 h 0 h

900

-900

AMANDA: Search for Point Sources

Angular resolution 3°

Future in ν telescopes: ANTARES1996 Started 1996 - 2000 Site exploration and demonstrator line2001 - 2004 Construction of 10 line detector, area ~0.1km2 on Toulon sitefuture 1 km3 in Mediterranean

Angular resolution <0.4° for E>10 TeV

2500m2500m

300m300mactiveactive

ElectroElectro--opticopticsubmarine cablesubmarine cable

~40km~40km

Junction boxJunction box

Readout cablesReadout cables

Shore stationShore station

anchoranchor

floatfloat

Electronics containersElectronics containers

~60m~60mCompass,Compass,tilt metertilt meter

hydrophonehydrophone

Optical moduleOptical module

Acoustic beaconAcoustic beacon

ANTARES 0.1km2 Detector

~100m

13 strings12 m between storeys

Region of sky seen by Neutrino Telescopes

AMANDA (South Pole) ANTARES (43° North)

Gamma ray flux >100 MeV observed by EGRET EGRET Source Type number of sources seen by Antares seen by Amanda

All 271 89% 43%

AGN 94 86% 52

Pulsars 5 100% 40%

Unidentified Gal. Plane 55 93% 36%

Unidentified off Gal. Plane 116 90% 40%

Complementary sky coverage, ANTARES sees Galactic CentreGreat hope for major discoveries

Never seen

seen<25% time

Indicative, assumesefficiency=100%for 2π downwards