English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We present the results of near-infrared [Fe II] and H2 line imaging andspectroscopic observations of the supernova remnant 3C 396 using the Palomar 5m Hale telescope. We detect long, filamentary [Fe II] emission delineating theinner edge of the radio emission in the western boundary of the remnant inimaging observations, together with a bright [Fe II] emission clump close tothe remnant center. There appears to be faint, diffuse [Fe II] emission betweenthe central clump and the western filamentary emission. The spectroscopicobservations determine the expansion velocity of the central clump to be ~56km/s. This is far smaller than the expansion velocity of 3C 396 obtained fromX-ray observations, implying the inhomogeneity of the ambient medium. Theelectron number density of the [Fe II] emission gas is < 2,000 cm-3. The H2line emission, on the other hand, lies slightly outside the filamentary [Fe II]emission in the western boundary, and forms a rather straight filament. Wesuggest that the [Fe II] emission represents dense clumps in the wind materialfrom the red supergiant phase of a Type IIL/b progenitor of 3C 396 which havebeen swept up by the supernova remnant shocks. The H2 emission may representeither the boundary of a wind bubble produced during the main-sequence phase ofthe progenitor or molecular clumps left over inside the bubble. We propose thatthe near-infrared [Fe II] and H2 emission observed in several supernovaremnants of Type IIL/b SNe likely has the same origin.

Near-Infrared [Fe II] and H2 Line Observations of the Supernova Remnant 3C 396: Probing the Pre-supernova Circumstellar Materials