new evidence for strong nonthermal effects in tycho’s supernova remnant leonid ksenofontov 1...
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New evidence for strong nonthermal
effects in Tycho’s supernova remnant
Leonid Ksenofontov1
H.J.Völk2, E.G.Berezhko1,
1Yu.G.Shafer Institute of Cosmophysical Research and Aeronomy, Yakutsk, Russia2Max-Planck-Institut für Kernphysik, Heidelberg, Germany
The Multi-Messenger Approach to High Energy Gamma-ray Sources, Barcelona, July 4-7, 2006
The model: supernova explosion
Vp
Vs
shock wave
ejecta (piston)
supernova
CRs
ISM: nH (~1 – 100 cm-3)
T (~104 – 106 K)
B0 (~1 – 100 μG)
SN: ESN (~1051 erg)
Mej (~1 Msun)
Vp0 (~105 km/s)
diffusive shock acceleration
3
f f
f f p Qt p
ww
c g
gg g g a g a c
0,
,
1 ,
t
P Pt
PP P c P
t
w
ww w
w w
3e e
e e e21
1
3
f f pf f p f
t p p p
ww
The model: basic equations
4
2 2 20
4
3
c
c p fP dp
p m c
Hydrodynamicequations
CR transport equationsfor protons and electrons
CR pressure 1 12
( ) ( )4
inj sinj
uQ p p r R
mpInjection term
ρ(r, t) – gas density
w(r, t) – gas velocity
Pg(r, t) – gas pressure
f(p, r, t) – CR distribution function
( ) ( )3
B
pcp p
eBCR diffusion coefficient
2 2
1 2 20
9
4 em c
r B pSynchrotron loss time
Völk et al. 2002, 2005About 10% of the explosion energy has been transferred into CR energy up to now, which means that the CR energy content is Ec = 0.1 Esn.
Distance determinations to Tycho’s supernova:
From the optical measurements d = 2.3 ± 0.8 kpc (Smith et al. 1991)
It is hard to escape from the uncertain range 2 – 4 kpc with the analyses done so far (Ruiz-Lapuente 2004)
What’s new:
From the Chandra measurements Warren et al. (2005) estimate a mean ratio of contact discontinuity (ejecta) radius to blast wave radius as 0.93
Badenes et al. (2005) found that the properties of the X-ray emission are well reproduced by a 1D delayed detonation model with a kinetic energy of ~ 1.2 × 1051 erg.
Conclusions:
HEGRA Upper Limit is consistent with the distance 3.3 − 4 kpc The expected π0-decay γ-ray energy flux is (2 − 5)×10−13 erg/(cm2s)
The new Northern hemisphere IACT such as MAGIC, VERITAS will be able to detect Tycho’s SNR
TeV gamma-rays predominantly have hadronic origin
Detection of a TeV signal is also important for the correct determination of key Supernova parameters
Total (π0-decay + IC) integral γ-ray energy fluxes as a function of γ-ray energy for the same four cases as in Fig.1. For comparison, the respective sensitivities for a 5σ detection in one year with GLAST (Weekes 2003, Proc. 28th ICRC, 8, 3), and in 50 hours at 20º zenith angle for a photon index 2.6 (as for the Crab Nebula) with H.E.S.S. (Funk 2005, in PhD thesis), are shown.