Neutrino Astronomy March 2005J. Goodman – Univ. of Maryland Neutrino Astronomy Why Neutrinos Questions in ultra high energy astrophysics –Source of UHE

March 2005J. Goodman – Univ. of MarylandNeutrino Astronomy

Neutrino Astronomy

• Why Neutrinos • Questions in ultra high energy astrophysics

– Source of UHE cosmic rays– GRBs– AGN– Other Physics Questions – DM, Top Down models, etc

• Understanding the W-B bound– Why the kilometer scale or bigger

• Overview of experimental approach– Cherenkov Detectors- IceCube – Nestor, Antares, Baikal– Radio - Rice, Anita, Salsa


Why Neutrinos


Why not protons?

• Protons are bent in the magnetic fields of our galaxy and local cluster

• Energy of >1019eV needed to point back to even galactic sources

• Above a few 1019eV GZK cutoff limits their range too


Effect of IR Absorption on Distant Sources

z = 0.03z = 0.1z = 0.2

z = 0

.3

z = 0.0

e+

e-

~eV

~TeV

• No direct measurement of IR extragalactic background light exists due to zodiacal foreground.

• TeV absorption constrains IR which depends on cosmology of galaxy and star formation models.

IR Model of Stecker & deJager (1998)


Photon Attenuation on IR


Questions in ultra high energy astrophysicsQuestions in ultra high energy astrophysics

Source of UHE cosmic rays

GRBs

AGN

Dark Matter

Other Physics Questions


Origin of Cosmic Rays

Extragalactic flux Extragalactic flux sets scale for manysets scale for manyacceleration modelsacceleration modelsAtmospheric

neutrinos

See Monday PM & Thursday

AM


Knee

Ankle

New component with hard spectrum?


Alternative Models

Bottom upBottom up

– GRB fireballs– Jets in active galaxies– Accretion shocks in

galaxy clusters – Galaxy mergers– Young supernova

remnants– Pulsars, Magnetars– Mini-quasars– …

• Observed showers either protons (or nuclei)

Top-downTop-down– Radiation from topological

defects– Decays of massive relic

particles in Galactic halo– Resonant neutrino

interactions on relic ’s (Z-bursts)

• Mostly pions (s,s,not

protons) • Disfavored!Disfavored!• Highest energy cosmic raysHighest energy cosmic rays• are not gamma raysare not gamma rays• Overproduce TeV-neutrinosOverproduce TeV-neutrinos



SNRs


HESS: RXJ1713

First resolved TeV -ray image of

a Shell type SNR (Resolution ~10

arcmin)

Acceleration source of Cosmic

Rays, but is it evidence of

Protons?


HESS: RXJ1713 – Molecular Clouds


RXJ1713 Spectrum

H.E.S.S.: full remnant

CANGAROO: hotspot

Index 2.2±0.07±0.1

preliminary

Index 2.84±0.15±0.20

In favor of 0:• no cut-off in the

HE tail of HESSspectrum

• signal from thedirection of

molecular clouds

See HESS Talk

Tuesday Afternoon


Have-rays from 0 decay been discovered?

E N (E) = E N (E)

1 < < 8transparent transparent sourcesource

00 = = ++ = = -

acceleratorbeam dump(hidden source)

flux predicted observed -ray flux

~40 per km2 ~40 per km2 RX J1713-3946 RX J1713-3946 per year (galactic center)per year (galactic center)


Milagro (TeV) Diffuse Source

See Milagro

Talk Tues Afternoon


Produces cosmic ray beamProduces cosmic ray beam

Radiation field:Radiation field:

Active Galactic Nuclei


Active Galactic Nuclei (AGN)

Fermi acceleration

Jets

Black Hole

Accretion Disk

Shock fronts


VLA image of Cygnus A

See Monday Morning

AGN Session


GZK

Gamma Beam Energy (GeV)

Cro

ss S

ect

ion (mb)

0.1

0.01

γ + p→Δ （1232）→ π o p or π + n


Cro

ss S

ect

ion (mb)

0.1

0.01

γ + p→Δ （1232）→ π o p or π + n


Cro

ss S

ect

ion (mb)

0.1

0.01

γ + p→Δ （1232）→ π o p or π + n

0.6 x 10-27 cm2

p

n p

π＋ μ＋

e＋

E = 6 x10 19 eV

E ~4 x 10 19 eV

p + p + CMBCMB →→ ++ + n + n

= = (n(ncmbcmb p + p + ))-1-1

= 10 Mpc= 10 Mpc

Cutoff above 50 EeVCutoff above 50 EeV


GZK

Cosmogenic neutrinos are guaranteed if primaries are nucleons.

May be much larger fluxes, for some models, such as topological defects


GZK

See Monday

PM + Thurs AM Sess.


GRBs


GRBs

Shocks: external collisions with interstellar material or internal collisions when slower material is overtaken by faster in the fireball.

See Wed AM+ Thu PM GRB sessions


eenp

e-

p+

R < 108 cmR 1014 cm, T 3 x 103

secondsR 1018 cm, T 3 x 1016 seconds

E 1051 – 1054 ergsShock variability is reflected in the complexity of the GRB time

profile.

6 Hours 3 Days

Radio

Optical

-ray

X-ray (2-10 keV)

Fireball Phenomenology & The Gamma-Ray Burst (GRB) Neutrino ConnectionFireball Phenomenology & The Gamma-Ray Burst (GRB) Neutrino Connection

Progenitor(Massive

star)Magnetic Field

---

Electron

-ray

Meszaros, P


Lorentz Invariance Violation

Bounds on energy dependence of the speed of light can be used to place constraints on the effective energy scale for quantum gravitational effects.

t ~ (E/EQG

) L/c

E2-c2p2~E2(E/EQG

)- This may be modified in some quantum gravity models.

This has the important observational consequence that this will giverise to energy dependent delays between arrival times of photons.

E2 = m2c4 +p2c2 - in the Lorentz invariant case,

The expected time delay is :

This may be measurable for very high energy photons/neutrinos coming from large distances.

See Wed. Afternoon


Galactic Microquasars

See Talk Monday Morning


What About Dark Matter?

• ~85% of the matter in the Universe is Dark Matter– At most a few % of the matter is baryons – Most people believe that the lightest SUSY particle is a

stable neutralino and is probably the dark matter– These are weakly interacting and heavy– Evidence of clustering

See Friday Afternoon

Session on Dark Matter


Wimp Capture

Earth

Detector


Wimp Detection


Neutrino Astronomy Explores Extra Dimensions

100 x 100 x SMSM

GZK rangeGZK range

TeV-scale gravity increases PeV TeV-scale gravity increases PeV -cross section-cross section

See Wednesday Afternoon Session


radiationenvelopingblack hole

black hole

p + p + -> n + -> n + ++

~ cosmic ray + neutrino -> p + -> p + 00

~ cosmic ray + gamma

Cosmic Neutrino Factory


W-B Bound


Evading the Bound

• “Neutrino only” sources that are optically thick to proton photo-meson interactions and from which protons cannot escape. – No observational evidence (from baryons

or high energy photons)• Cores of AGNs (rather than in the jets) by

photo-meson interactions or via p−p collisions in a collapsing galactic nucleus or in a cacooned black hole.– The most optimistic predictions of the

AGN core model have already been ruled out by AMANDA


Mannheim, Protheore and Rachen Model


Neutrinos from Cosmic Rays

~50 events/km2/yr


Size Perspective for KM3

50 m

1500 m

2500 m

300

m

AMANDAII


Detection Technique

neutrino

muon or tau Cerenkov

light cone

detector

interaction

•The muon radiates blue light in its wake

•Optical sensors capture (and map) the light

See Talks in this

Session


Detection ofe

~ 5 m

Electromagnetic and hadronic cascadesO(km) long muon tracks

direction determination by cherenkov light timing

17 m


Eµ= 10 TeVEµ= 6 PeV

Measure energy by counting the number of fired PMT. (This is a very simple but robust method)

Muon Events


Determining Energy

10 TeV 6 PeV 375 TeV Cascade


Double Bang

+ N -->- + X

+ X (82%)

E << 1PeV: Single cascade (2 cascades coincide)E ≈ 1PeV: Double bangE >> 1 PeV: partially contained (reconstruct incoming tau track and cascade from decay)

Regeneration makes Earth quasi transparent for high energie ;(Halzen, Salzberg 1998, …)Also enhanced muon flux due to Secondary µ, and µ

(Beacom et al.., astro/ph 0111482)

Learned, Pakvasa, 1995


Tau Cascades

E << 1PeV: Single cascade (2 cascades coincide)E ≈ 1PeV: Double bangE >> 1 PeV: partially contained (reconstruct incoming tau track and cascade from decay)


Neutrino ID (solid)Neutrino ID (solid)Energy and angle (shaded)Energy and angle (shaded)

e

Log(energy/eV)12 18156 219

e

Neu

trin

o fl

avor


Tau Transparency/Regeneration

• e and µ are absorbed in the Earth via charged current interactions (muons range out)

• Above ~100 TeV the Earth is opaque to e & νµ.

• But, the Earth never becomes completely opaque to

• Due to the short lifetime, ’s produced in charged-current

interactions decay back into • Also, secondary e & νµ. fluxes are

produced in the tau decays.


Flavor Ratios

• The ratio of flavors at the source is expected to be 0:2:1= : : e

• Since the distance to the source is >> than the oscillation length – any admixture at the source should wind up:

1:1:1= : : e

when arriving at earth

• What if that isn’t true?


Exotic neutrino properties if not 1:1:1

• Neutrino decay (Beacom, Bell, Hooper, Pakvasa& Weiler)

• CPT violation (Barenboim& Quigg)

• Oscillation to steriles with very tiny delta δm2

(Crocker et al; Berezinskyet al.)

• Pseudo-Dirac mixing (Beacom, Bell, Hooper, Learned, Pakvasa& Weiler)

• 3+1 or 2+2 models with sterile neutrinos (Dutta, Reno and Sarcevic)

• Magnetic moment transitions (Enqvist, Keränen, Maalampi)

• Varying mass neutrinos (Fardon, Nelson & Weiner; Hung & Pas)


Amanda-II

Amanda-B10

IceCube

0 5 10 sec

Count rates

Supernova Monitor

B10: 60% of Galaxy

A-II:95% of Galaxy

IceCube:up to LMC


Large Scale Neutrino Detectors

NESTOR Pylos, Greece

ANTARESANTARESLa-Seyne-sur-Mer, FranceLa-Seyne-sur-Mer, France

BAIKAL Russia

IceCube, South Pole, Antarctica

NEMOCatania, Italy

See Talks in this

Session


Radio Cherenkov Detectors

Rice Anita Salsa


Acoustic Detectors

SAUND(Study of Acoustic Underwater Neutrino Detection)


Conclusions

Now Soon Future

Amanda Cherenkov arrays ???

SK Radio Detectors

Neutrino Astronomy is just beginning to open a new window on the Universe!

Documents

Neutrino Astronomy March 2005J. Goodman – Univ. of Maryland Neutrino Astronomy Why Neutrinos Questions in ultra high energy astrophysics –Source of UHE