Post on 04-Aug-2020
transcript
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