Neutrino Astronomy

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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

Slide 2

Why Neutrinos

Slide 3

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

Slide 4

Effect of IR Absorption on Distant Sources

e+

e-

~eV g

~TeV g

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)

Slide 5

Photon Attenuation on IR

Slide 6

Questions in ultra high energy astrophysics

Source of UHE cosmic rays

GRBs

AGN

Dark Matter

Other Physics Questions

Slide 7

Origin of Cosmic Rays

Extragalactic flux

sets scale for many

acceleration models

Atmospheric

neutrinos

See Monday PM & Thursday AM

Slide 8

Slide 9

Alternative Models

Bottom 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-down

Radiation from topological defects

Decays of massive relic particles in Galactic halo

Resonant neutrino interactions on relic n’s (Z-bursts)

Mostly pions (ns,gs,not protons)

Disfavored!

Highest energy cosmic rays

are not gamma rays

Overproduce TeV-neutrinos

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