High Energy Neutrinos from Astrophysical Sources Dmitry Semikoz UCLA, Los Angeles & INR, Moscow.

High Energy Neutrinos High Energy Neutrinos from Astrophysical from Astrophysical

Sources Sources

Dmitry SemikozDmitry SemikozUCLA, Los Angeles & INR, MoscowUCLA, Los Angeles & INR, Moscow

Ultra High Energy \\ Cosmic Rays

Neutrino Oscillation Workshop, September 16, 2004

Overview: Introduction: cosmic rays, gamma-rays and neutrinos Diffuse neutrino fluxes

Neutrinos from UHECR (Friday, F.Halzen , G.Miele) Neutrinos from AGN

Most probable point-like neutrino sources AGN Galaxy center Microquasars SuperNova high energy E>TeV neutrinos GRB (Friday, P.Meszaros)

Conclusion


INTRODUCTION


Conditions required for production of high energy neutrinos in astrophysical sources:

Acceleration of charged particles (protons or nuclei) to high energies E>1015 eV

Accelerated particles should lose energy through pion production or neutron decay

Obey gamma-ray and neutrino flux limits

1 pBBnR


Neutrinos from pion production

ee

...

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i

b

i

b

PP

NN

p

n

20

eepn

Conclusion: photon and neutrino fluxes are connected in well-defined way. If we know one of them we can predict other: tottot EE ~


High energy photons from pion decay cascade down in GeV region


The high energy gamma ray detector on the Compton Gamma Ray Observatory (20 MeV - ~20 GeV)

EGRET: gamma-ray flux


Photon flux at E>100 MeV as measured by EGRET till 1995

The Flux of Diffuse Photons Point sources


The next-generation ground-based and space-based experiments are well matched.

Complementary capabilities

ground-based space-based ACT EAS Pairangular resolution good fair goodduty cycle low high higharea large large smallfield of view small large large+can reorient

energy resolution good fair good, w/ smaller systematic uncertainties

High energy gamma ray experiments


EGRET flux can consist of:

Inverse Compton scattered photons Synchrotron photons from high energy

protons Photons from pion decay, which cascade

down in intergalactic space or in source Thus EGRET flux give just upper limit on

diffuse or point source neutrino flux


Diffuse flux of neutrinos


Cosmic rays and AGNs

Diffused flux from cosmic rays Many unresolved sources

AMANDA II


GLAST: 10000 sourcesLAT 1st Catalog: >9000 sources possible


AGN as neutrino sources


Only few classes of astrophysical objects are able to accelerate particles to highest energies

For neutrino production we have to look for the sources with high density of background photons or protons


Can sources accelerate protons to such high energies? AGASA data E> 1019 eV:

AGNs are one of most probable sources


Neutrino production in AGN core


Neutrinos from AGN core

AMANDA II

J.Alvarez-Muniz and P.Mezsaros, astro-ph/0409034


Most probable point-like neutrino

sources


Point source fluxes

Background of atmospheric neutrinos against flux of given source. Position of source given a priori.

AMANDA II 1.8 degrees resolution: 3 background 6 observed

ANTARES 0.3 degrees ICECUBE 0.5 degrees KM^3 0.3 degrees<


Most probable single sources- AGN

Blazars GeV-loud Optical depth for

protons should be large:

pnR

Only 22 sources from 66 are GeV - loud


TeV blazars does not obey last condition

Indeed, in order TeV blazars be a neutrino sources:

pnR nRp= 6x10-28cm2 while for TeV gamma-rays

= 6.65 x 10-25cm2

CONTRADICTION!!! Except if proton background density is as high as photon one, because pp= 6x10-26cm2 This is unlikely in BL Lacs, where emission lines are absent.


Which sources ?

Blazars (angle – energy correlation) Blazars should be GeV loud Optical depth for protons should be large:

pnR No 100 - kpc scale jet detected (model-dependent)


Neutrino production in AGN


Bound on blazars which can be a neutrino sources

A.Neronov, D.S., 2002


Collimation of neutrino flux in compare to GeV flux

AMANDA II


Galaxy center: cosmic rays

AGASA experiment see anisotropy towards the Galactic center.

This signal can be explained by neutrons.


Galaxy center

Cosmic ray neutrons decay on the way and produce neutrinos.

L.Archadoqui, H.Holdberg, F.Halzen and T.Weiler, astro-ph/0311002

eepn


Microquasars

AGN on star scales. Protons are

accelerated by shock wave up to 1016 eV

In interaction with X-ray photons from accretion disk protons produce 1-100 TeV neutrinos

A.Levinson and E.Waxman, 2001C.Distefano et al, 2002

psEFE

1.0

cm

eV10)(

222


Galactic SN When shock came out of star it

start to accelerate protons. Up to 200 events with E>1 TeV

in ICECUBE within few hours (E.Waxman and A.Loeb, astro-ph/0102317)

Extra 1000-10000 events in first year (V.Berezinsky and V.Ptuskin, 1988)

Can help to detect SN location up to 0.1 degree. (R.Tomas, D.S., G.Raffelt, M.Kachelriess and A.Dighe, hep-ph/0307050)

Supernova 1987A Supernova 1987A 23 February 198723 February 1987


Conclusions Diffuse neutrino flux can be combination of cosmic ray and

AGN neutrinos. GeV-loud blazars with high optical depth for protons are good

candidates for point-like neutrino sources.

Galaxy center can be good source of neutrinos and flux can be predicted based on AGASA signal.

Galactic microquasars, GRB, galactic SN are sources of neutrinos.

We have a good chance to detect those sources with km2 detectors.

High Energy Neutrinos from Astrophysical Sources Dmitry Semikoz UCLA, Los Angeles & INR, Moscow.

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