Neutrinos as probes of ultra-high energy astrophysical phenomena Jenni Adams, University of Canterbury, New Zealand

up to 10 MeV MeV GeV – 10sTeV Neutrino sources J. Becker Phys. Rep. 458

How do we know there are high energy astrophysical phenomena? Observe high energy particles Observe radiation that is indicative of high energy processes There might be hidden sources…

Cosmic messengers

Astroparticle physics High energy photon astrophysics astroparticle physics Neutrino astrophysics Cosmic ray astrophysics

Origin of the ultra-high energy cosmic rays? ?

How do we accelerate a particle? Fermi Acceleration

How do we accelerate a tennis ball? Not with a steady tennis racket!

Need a moving racket

Back to particles… ball ↔ charged particle racket ↔ magnetic mirror

Fermi Acceleration 2 nd Order: randomly distributed magnetic mirrors slow and inefficient 1 st Order: acceleration in strong shock waves

Hillas Plot What condition is used to estimate the maximum energy which can be obtained from a given site? The gyroradius is less than the linear size of the accelerator

Auger sky map At energies > 6 X eV can get indications of origin (why not a lower energies?) significance reduced in larger data set…?

How do we know there are high energy astrophysical phenomena? Observe high energy particles Observe radiation that is indicative of high energy processes There might be hidden sources…

Non-thermal radiation – what do we mean by non-thermal?

Nature’s accelerators

Information from Gamma-Rays Lots of sources identified Morphology of galactic sources resolved but most sources can be described by leptonic models as well as hadronic

Source of the highest energy cosmic rays Why detect neutrinos?

Neutrino production p + p or p +  give pions which give neutrinos eg. p    +   + n/  0 p –  +   +   e + e   –  0    (E  ~TeV) Animation generated with povray

Why detect neutrinos? Figure: Wolfgang Wagner, PhD thesis

Krawczynski et al., ApJ 601 (2004) BL Lac Object

Short, intense, eruptions of high energy photons, with afterglow detected in X-ray to radio Isotropic distribution in the sky Bimodal distribution of burst times Non-thermal photon spectrum Energy output of erg to erg What can you tell us about GRBs? Accidentally discovered by the military Vela satellites in the late 1960’s

Progenitors Long duration bursts result from collapse of massive star to black hole –GRB observed by HETE II linked to type 1C Supernova –Long duration bursts in galaxies with young massive stars Short duration bursts result from collision of some combination of black holes and neutron stars –GRB050509B observed by Swift with limited afterglow –Appears to have occurred near a galaxy with old stars Theories may be rewritten by Swift observations –050502B X-ray spike after burst, indications of multiple explosions

GRB progenitors duration > 2 s typically ~ 40 s duration < 2 s ~ms - s Animated movies: Nasa Long GRBs  Supernova ExplosionsShort GRBs  binary mergers

Fireball Model Radiation dominated soup of leptons and photons implied by high optical depth Radiation pressure drives relativistic expansion of material outward M. Aloy et al. ApJL2000

Inner Engine Relativistic Wind External Shock Afterglow Internal Shocks  -rays But observed spectrum is non-thermal and significant energy is expected to be transferred to the baryonic content in the wind

Shock fronts Afterglow produced in external shocks – softened spectrum due to decreasing Lorentz factor Prompt  –ray emission produced by dissipation of fireball kinetic energy in internal shocks - supported by microstucture

Burst spectrum GRB1122    b = ± 2.1 keV  = ±  = ± 0.07  bbbb Band et al., ApJ 413 (1993)

Burst spectrum    b = 100 – 300 keV  ~ - 1  ~ -2  bbbb Synchrotron radiation from accelerated electrons Inverse Compton scattering

Example of neutrino spectrum for high energy astrophysical object – GRB Spectrum

Example of neutrino spectrum

GRB Spectrum (I) e.g. Waxman/Bahcall, hep-ph/

Highest energy pions lose energy via synchrotron emission before decaying reducing the energy of the decay neutrinos Effect becomes important when the pion lifetime is comparable to the synchrotron loss time Neutrino spectrum steepens by a power of two after this second break energy GRB Spectrum (II)

   

GRB Spectrum (III) f  : fraction of proton energy going into pions f e : fraction of electron to proton total energy  charged pions   per particle ax

Neutrino production p + p or p +  give pions which give neutrinos eg. p    +   + n/  0 p –  +   +   e + e   –  0    (E  ~TeV) Animation generated with povray

IceCube and fundamental physics

up to 10 MeV MeV GeV – 10sTeV Neutrino sources J. Becker Phys. Rep. 458

Other neutrino detectors in proportion Super Kamiokande SNO

AMANDA, RICE, IceCube, ANITA ANTARES NEMO NESTOR KM3NET Lake Baikal DUMAND Neutrino telescopes around the globe

Topological Flavour Identification   produce long  tracks  Angular resolution ~ 1 0  e CC, x NC cause showers  ~ point sources ->’cascades’  Good energy resolution   ‘double bang events  Other  topologies under study Muon – IC 40 data  PeV   simulation e (cascade) simulation

Neutrino-nucleon cross-section

Earth becomes opaque for e  and  

Coming to a cinema (conference, journal) near you soon… Astrophysical neutrinos caught Neutrinos