Electron Scattering Wings on Lines in Interacting Supernovae

Document Type

Article

Publication Date

3-21-2018

Publication Title

Monthly Notices of the Royal Astronomical Society

Volume

475

Issue

1

First page number:

1261

Last page number:

1273

Abstract

We consider the effect of electron scattering on lines emitted as a result of supernova interaction with a circumstellar medium, assuming that the scattering occurs in ionized gas in the pre-shock circumstellar medium. The single scattering case gives the broad component in the limit of low optical depth, showing a velocity full width half-maximum that is close to the thermal velocities of electrons. The line shape is approximately exponential at low velocities and steepens at higher velocities. At higher optical depths, the line profile remains exponential at low velocities, but wings strengthen with increasing optical depth. In addition to the line width, the ratio of narrow to broad (scattered) line strength is a possible diagnostic of the gas. The results depend on the density profile of the circumstellar gas, especially if the scattering and photon creation occur in different regions. We apply the scattering model to a number of supernovae, including Type In and Type Ia-circumstellar medium (CSM) events. The asymmetry to the red found in some cases can be explained by scattering in a fast wind region that is indicated by observations.

Keywords

Shock waves; Circumstellar matter; Supernovae: general

Disciplines

Astrophysics and Astronomy

Language

English

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