Non-Maxwellian Velocity Distributions on Tycho’s SNRJ.C. Raymond, P.F. Winkler, W.P. Blair, J.J. Lee, S. Park

Balmer lines Profiles

H from H atoms excited before ChargeTransfer form Narrow Component.

H from atoms excited after ChargeTransfer form Broad Component.

H I

e-

proton

h

Ghavamian et al. 2002

Shock

Narrow Component Unresolved

Broad post-shock f(v) (weighted by CX

Heng & McCray)

Tycho’s SNR Shock

HST; Lee et al.

MMT slit positionsAlso HET spectra of 4 positions

2 and 3 Gaussian fits to profile

FWHM = 1540 km/sV = 120 km/s

FWHM = 1160, 2230 km/sV = 115, 140 km/s

Explanations:

Superposition of different Proton Temperaturesalong LOS

Fits give factor of 2 difference in FWHM, which implies factor of 4 in n0

Implies rapid changes in morphology

Charge Transfer velocity dependence Heng, van Adelsberg, McCray Cuts off wings rather than enhances, but sums different profiles. Looks like Gaussian for 2000 km/s

Van Adelsberg et al.

MORE Explanations

Modified Shock

Continuous range of T Blends Narrow & Broad components? Subshock jump could be 2X.

Power Law Tail

Vladimirov et al.

Non-Maxwellian Proton Distributions

Potentially Important for Injection as well as Diagnostics

Neutrals ionized downstream are like Pickup Ions (Related to ACRs)

VSVS/4

VPERP = ¾ VS SinVPAR = ¾ VS Cos

Bispherical Velocity Distribution Thermal + Pickup Distribution

Proton Velocity Distribution

Formation of bispherical distribution transfers energy to waves; may heat protons or electrons.

Raymond, Isenberg & Laming

Better fit than two GaussiansNot as good as three, but fewer free parametersParameter space not fully explored

In Conclusive

Good enough data reveal non-Gaussian profiles

Superposition of different T must happen at some level

Pickup Ion profiles must be present at some level

Charge transfer distortion of profile probably not important in Tycho

CR modified shock temperature profile might contribute

Power law tail due to acceleration might contribute