12-20 July 2017
BEXCO
Asia/Seoul timezone
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Contribution

BEXCO - Room F(201/202/203/204)

[CRI193] Shock precursors in the northeastern rim of Tycho's supernova remnant

Speakers

  • Sladjana KNEZEVIC

Primary authors

Co-authors

Description

We present Halpha spectroscopic observations and detailed modelling of Balmer filaments in the northeastern rim of Tycho's supernova remnant. Balmer filaments are bright sheets of shocked gas seen edge-on that trace collisionless, non-radiative forward shock which propagates in partially ionized medium. Collisional excitations of unshocked neutral hydrogen and charge-exchange processes between shocked protons and unshocked neutrals produce a narrow (~ 10 km/s) and a broad (~ 1000 km/s) Halpha components, respectively. The observed two-component Halpha profiles constrain ISM and shock properties, and possible pre-shock heating processes. We will present observations of narrow Halpha profiles which we have analysed using Bayesian inference to obtain reliable parameter estimates and quantify the evidence for more complex models than the fiducial single narrow-line model. Not only that the narrow Halpha-line width is much larger than the maximally allowed thermal broadening of 20 km/s across the entire Tycho’s northeastern rim, but we also show that this broadening is not due to the projection effects. In addition, we also find several locations along the rim that demand inclusion of an additional intermediate component with the width of ~ 100 km/s. Suprathermal narrow line widths (~ 53 km/s) are currently explained only by cosmic-ray proton acceleration in the shock, while the intermediate component arises in the processes within the neutral-induced precursor.