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 Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

X-ray observations of supernova remnants (SNRs) in the last decade have shownthat the presence of recombining plasmas is somewhat common in a certain typeof object. The SNR W49B is the youngest, hottest, and most highly ionized amongsuch objects and hence provides crucial information about how the recombinationphase is reached during the early evolutionary phase of SNRs. In particular,spectral properties of radiative recombination continuum (RRC) from Fe are thekey for constraining the detailed plasma conditions. Here we present imagingand spectral studies of W49B with Nuclear Spectroscopic Telescope Array(NuSTAR), utilizing the highest-ever sensitivity to the Fe RRC at > 8.8keV. Weconfirm that the Fe RRC is the most prominent at the western part of the SNRbecause of the lowest electron temperature (~ 1.2 keV) achieved there. Ourspatially-resolved spectral analysis reveals a positive correlation between theelectron temperature and the recombination timescale with a uniform initialtemperature of ~ 4 keV, which is consistent with the rapid adiabatic coolingscenario as an origin of the overionization. This work demonstrates NuSTAR'ssuitability for studies of thermal emission, in addition to hard nonthermalX-rays, from young and middle-aged SNRs.

Evidence for Rapid Adiabatic Cooling as an Origin of the Recombining Plasma in the Supernova Remnant W49B Revealed by NuSTAR Observations