Thermal X-ray in SNRThermal 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 thermal

radiation mechanism

synchrotron ejecta shocked gasreflected shock forward shock

model powerlaw vnei(hard to fit)

vnei apec

note P index is 2.5 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 0102.2-7219, 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