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Goals
• Construction of a hadronic model for the
production of neutrinos and the associated
gamma-rays in galactic sources
• Prediction of neutrino signals in TeV-range
(c.f. IceCube –south; Nemo -north)
• Analysis of correlated gamma-ray detection:
luminosity and opacity
(c.f. MAGIC: Major Atm. Gamma Imaging Cerenkov E>30GeV –North
HESS: High Energy Stereoscopic System E>100GeV –South
GLAST satelite E>100MeV)
Motivation:
• High energy neutrinos can provide crucial data
for the understanding of the origin of cosmic
rays: where they come from, how are they
produced, how are they accelerated ...
• Neutrinos point straight to the source thus
avoiding ambiguities, and are not absorbed
along their long way
Cosmic Rays (CR)
• 86 % protons, 11% alphas, 2% electrons and 1% heavy íons.
NB: This 1% is particularly large as compared with the same
quantity in the solar system (e.g. Li, Be, B, are several orders
less present).
• Most CR are relativistic (even ultra-relativistic, > 10(20) eV, of
most enigmatic origin).
• Most are non-solar but still galactic.
• Interstellar secundaries are produced in primary CR versus
interstellar íons collisions: their study can shed light on fields
and particles of interstellar medium.
• Neutrinos and photons secundaries produced near the source
can explain their origin and the mechanism involved
Where to look for:
•
In our Galaxy, in (compact object + massive star) binary
systems
Why:
•
compacts exhibit strong magnetic fields
potential
accelerators, massive stars present circumstellar matter
fields
lot of material for particle collisions.
•
Be /X binary systems present strong and variable radio
and X ray emission, and are found within positional error
boxes of gamma ray sources probably galactic
probability of correlated neutrinos.
•
Disruption of magnetic fields can generate ejection
phenomena : bipolar jets.
Microquasars: binary systems with jets.
Primary: massive B star, generates a matter field
around.
Secondary: compact object, a mass accretor, generates
a jet (neutron star or BH, determined by Doppler
shift of absortion lines of the primary –analysis of
changes of radial velocity vs. orbital position).
Miniatures of quasars.
• LS I +61 303 is a galactic Be/X binary (den Heuvel &
Rapapport 1987) distant 2.0  0.2 kpcs (Frail & Hjellming
1991) presents strong periodic radio emission (Gregory
et al. 1979) and moderated periodic X (inverse-Compton)
(Harrison et al. 2000).
• Persistent radio bursts 2.5 - 4 days after periastron.
• LS I already associated with gamma ray sources 2CG
135 +01 (Kniffen et al. 1997), and 3EG J0241 +61 03
(Hartman et al. 1999). Recently stated by EGRET main
peak coincident with periastron (Massi 2004)
Explanation: Microquasars, bizarre binary star systems generating high-energy radiation and blasting out jets of particles at
nearly the speed of light, live in our Milky Way galaxy. The energetic microquasar systems seem to consist of a very compact
object, either a neutron star or a black hole, formed in a supernova explosion but still co-orbiting with an otherwise normal star.
Using a very long array of radio telescopes, astronomers are reporting that at least one microquasar, LSI +61 303, can be
traced back to its probable birthplace -- within a cluster of young stars in the constellation Cassiopeia. About 7,500 light-years
from Earth, the star cluster and surrounding nebulosity, IC 1805, are shown in the deep sky image above. The cluster stars are
identified by yellow boxes and circles. A yellow arrow indicates the common apparent motion of the cluster stars, the green
arrow shows the deduced sky motion of the microquasar system, and the red arrow depicts the microquasar's motion relative
to the star cluster itself. Seen nearly 130 light-years from the cluster it once called home, a powerful kick from the original
supernova explosion likely set this microquasar in motion. Credit: I. F. Mirabel, I. Rodrigues, Q. Z. Liu, NRAO / AUI / NSF
2004 September 24
• Primary: B0 V [white-blue,10-18 M  , main seq.
M (Be)
(dwarf)] dense fast matter wind - equatorial disc
(Hutchings & Crampton 1981, by UV spectroscop.
Paredes & Figueras 1986, photometr. anal.) orbit
26.5 days (radio, Gregory 2002), high eccentricity
0.72 (IR spectrosc., Martí & Paredes 1995).
• Secundary: probably neutron star with a bipolar jet of
200 AU each (dist. Earth-Sun).
• Presumed presence of protons in the jet. c.f.
microquasar SS 433 (first discovered, Margon 1979)
íons detected in jet (Migliari al. 2002, X ray analysis).
Scketch of Model
Model of microquasar LSI



Be starcircumstellar disc distribution density
(Marti & Paredes 1995, Gregory & Neish 2002)
wind velocity
Everything given by orbital position (keplerian)
major semiaxes a, high eccentricity e= 0.72
(psi=0.23 at periastron, Casares 2005)
pp




Mass accretion rate depends on relative velocity of neutron
star with respect to the (radial) wind velocity.
Accretion rate and jet kinetic power are proportional (Falcke &
Biermann 1995)
For jet cold protons qj=0.1 (Lorentz factor  = 1.25, Massi et
al. 2001). qj =0.01 – 0.001 for relativistic jet protons.
Conic jet, normal to orbital plane, with injection point and radius
at base R0 = z0 /10
High energy neutrinos:
arise from collisions of relativistic (jet) protons and
cold (wind) protons after pion decay


On average, 1/3 of the energy goes into each flavor
Both products are easily correlated:
2   and 2   mean energy E  /4 each, for each
energy E  /2
E = E / 2



mean
Microscopics




Proton flux along the jet axis (ph/erg cm2 s): power law
 =2.2 (reproduces EGRET obs.);
in lab/observer frame
-approx. emerging photon
 angle between proton and jet axis
o
or observing position:    obs  30
 bulk vel. (c units).
(Casares et al. 2005)
Ko normalization cons., related to particle density at base
(Romero et al. 2003)
Magnetic field, Penetration and Acceleration

Provided p gyro-radius smaller than cone radius, it can
penetrate inside. Magnetic field must be

namely Bjet>2.8 10^-6 G
shock formation in boundary layers prevents penetration thus
introduce a penetration factor fp = 0.1 (reproduces GeV gamma
ray flux observed by EGRET)
Admitting

Difussive particle acceleration by quasi-parallel shocks

Adiabatic field and matter evolution along the jet

Equipartition of energy between B and jets cold protons

Larmor radius= jet radius then proton Emax
Maximal magnetic field and maximal jet proton energy
Pion Multiplicity 





For Ep<10TeV (Mannheim & Schilckeiser 1994)
For Ep higher we extrapolate with a 1/5 power such
that psi=14 at Ep=100 TeV (Orth 1976) and for
Ep>100TeV with 1/6 power implying psi=26 for
Ep=50PeV
(Ginzburg & Syravatskii)
K=0.5 inelasticity coef. (on average, pions leave the
fireball with half the max. energy)
E =1/2 E  (aver. kinematics)
Maximal neutrino energy
(it results from orbital variation of
maximal proton energy and pion multiplicity)
Neutrino Signal (& noise)

Convolution of source intensity and event probability

Convolution of atmospheric flux
Flux of neutrinos out of gamma flux
Conservation of energy relates luminosities of neutrino
& gamma
Average production kinematics in
In the reaction channel pp: D =1

decay

Spectral intensity (ph/s erg):
V : interaction region between jet & wind

Density of wind particles penetrating the jet

Gamma-ray emissivity from  0 decays
(e.g. Aharonian & Atoyan 1996):


Z  p spectral moment, related to the fraction of
kinetic energy transferred to the pion (Gaisser 1990)
 A =1.4 takes into account the contribution of
different nuclei in wind and jet
TeV-neutrino events detectable by
ICECUBE
Production of mu-neutrinos at the source
(c.f. upper limit of AMANDA II 2005)
Neutrino mixing
flavor oscillations (e.g. SNO 2002, solar).
Relative neutrino production at source (pp):
Becomes 1
such that
: 1 : 1 for astrophysical distances
50% reduction mu-nu flux
(Costantini & Vissani 2005)
(Athar et al. 2005)
Total luminosity LSI


From 30 GeV up to:
(vide MAGIC 2005)
Excess (x4) over experimental limit for total intensity for
E  >350 GeV (Fegan et al. 2005):
Local (source) Opacity

Optical depth for a
E gamma ray among Eph ambient photons
distance to the neutron star: 
Threshold for pair creation: Emin  (mec ) / E
2 2
Cross section of the reaction:
me, r0 electron mass and radius
Main contributions given by photon densities
nph1 (Be star), and nph2 (disk)

The black body bright function
Teff,1= 22500 K, Teff,2= 17500 K (Martí & Paredes 1995).
Opacity: optical depth
(gamma) Luminosity and Opacity
Conclusions




Model for production of galactic neutrinos and
correlated gamma-rays: hadronic origin.
case study: microquasar LSI (recent parameters)
Predictions compatible with observed periodicity in
gamma frequencies (EGRET 2004). Pronounced
peak at periastron, secondary maximum near
apastron in contrast with radio/X frequencies.
(lepton models have difficulties with this).
Predictions of luminosity (source) and detectability:
neutrino signal to noise relationship, and gamma
opacity: correlated ICECUBE and MAGIC briefly…