Suzaku Observations of Thermal and Non-Thermal X-Ray Emission from the Middle-Aged Supernova Remnant G156.2+5.7

TL;DR

This study uses Suzaku X-ray observations to analyze the thermal and non-thermal emissions of the middle-aged supernova remnant G156.2+5.7, revealing details about its composition, shock acceleration, and explosion type.

Contribution

First detailed Suzaku X-ray analysis of G156.2+5.7 revealing its thermal and non-thermal emission characteristics and progenitor type.

Findings

Soft and hard X-ray emissions confirmed in specific regions.

Ejecta composition indicates a core-collapse supernova from a progenitor less than 15 solar masses.

Non-thermal synchrotron emission likely from relativistic electrons accelerated by a slow forward shock.

Abstract

We present results from X-ray analysis of a Galactic middle-aged supernova remnant (SNR) G156.2+5.7 which is bright and largely extended in X-ray wavelengths, showing a clear circular shape (radius about 50'). Using the Suzaku satellite, we observed this SNR in three pointings; partially covering the northwestern rim, the eastern rim, and the central portion of this SNR. In the northwestern rim and the central portion, we confirm that the X-ray spectra consist of soft and hard-tail emission, while in the eastern rim we find no significant hard-tail emission. The soft emission is well fitted by non-equilibrium ionization (NEI) model. In the central portion, a two-component (the interstellar medium and the metal-rich ejecta) NEI model fits the soft emission better than a one-component NEI model from a statistical point of view. The relative abundances in the ejecta component suggest that G156.2+5.7 is a remnant from a core-collapse SN explosion whose progenitor mass is less than 15 M_solar. The origin of the hard-tail emission is highly likely non-thermal synchrotron emission from relativistic electrons. In the northwestern rim, the relativistic electrons seem to be accelerated by a forward shock with a slow velocity of about 500 km/sec.