Transcript Thermal X-ray in SNR

Thermal X-ray in SNR
Patrick Slane
Zhang Ningxiao
three regions
• fast shocks in SNR heat matter to millions
of degrees
• 1.behind the forward shock, ISM heat by
forward shock
• 2.interior to the SNR, cold eject heat by
reverse shock
• 3.outside PWN, eject heat by expand
nebular
The components inside the SNR
synchroton non-thermal
radiation
mechanism
synchrotron
model
powerlaw
note
P index is 2.5
thermal
ejecta
shocked gas
reflected shock
forward shock
vnei
(hard to fit)
vnei
apec
lots of
emission
lines
really high
temperature
& low τ
low
temperature
electron temperature
• lower than the ion (low mass)
• the detected temperature is lower than
estimate.
• 1) slow temperature equilibration
• 2) cosmic-ray acceleration
• In some case, high Te/Tp provide
equilibration. Electron heated by lower
hybrid waves. (Balmer lines, high-res
spectra)
τ
• The plasma reaches collisional ionization
equilibrium forτ>=10^12.5 cm^-3 s; if τ is
lower than this, means nonequilibrium
ionization.
• The Chandra observation of 1E 0102.27219, show a smaller radius of OVII than
OVIII. And this indicates reverse shock
heated the eject. The same thing in
G292.0+1.8 for forward shock.
overionized
• In some case, the ionization temperature
is higher than Te indicates an overionized
plasma.(W49B)
• rapid expansion and adiabatic cooling
have lowered the plasma temperature to a
value below its ioniztion state.
Ejecta
• define the type of SNRs.
• Type Ia dominated by Fe,
• Type II contain much larger amounts of O
• When the SNR is young the thermal X-ray
spectra provide rich information of ejecta.
Example
•
•
•
•
Kepler's SNR Type Ia (dominate Si, S, Fe)
Based on this CC always asymmetric
1) the environments
2) itself
Shocked Circumstellar Material
• RSG or WR wind episodes is expected to
show the signatures of CNO cycle, leads
to an environment with enhanced N/O
ratio. so study the X-ray behind the FS can
lead us know late-phase properties of the
progenitor star. (type, age, mass...)
Example
• G296.1-0.5 RGS spectra shows
overabundance of N and an
underabundace of O, this indicate a result
of CC event from a fairly massive
progenitor.
Particle Acceleration(?)
• Much of this evidence is provided by
synchorotron radiation significant
information is provided by thermal X-ray
emission as well. (1E 0102.2-7219)
• The temperature of X-ray is much lower
than indicate from shock velocity. --> more
energy accelerate particles instead of
heating the gas. (Tycho,FS and RS small)
• need a factor of 100!!!
phabs*vnei
• Thank you