Molecular Clouds associated with the Type Ia SNR N103B in the Large Magellanic Cloud

TL;DR

This study investigates the molecular environment of the Type Ia supernova remnant N103B in the Large Magellanic Cloud, revealing a giant molecular cloud and expanding gas motions, supporting a single-degenerate progenitor scenario.

Contribution

First detailed CO observations of N103B revealing molecular clouds and gas dynamics, supporting the wind-bubble explosion model for Type Ia supernovae in the LMC.

Findings

Confirmed a giant molecular cloud near N103B

Detected expanding gas motion with ~5 km/s velocity

Supported the single-degenerate progenitor scenario

Abstract

N103B is a Type Ia supernova remnant (SNR) in the Large Magellanic Cloud (LMC). We carried out new $^{12}$CO($J$ = 3-2) and $^{12}$CO($J$ = 1-0) observations using ASTE and ALMA. We have confirmed the existence of a giant molecular cloud (GMC) at $V_\mathrm{LSR}$ $\sim$245 km s$^{-1}$ towards the southeast of the SNR using ASTE $^{12}$CO($J$ = 3-2) data at an angular resolution of $\sim$25$"$ ($\sim$6 pc in the LMC). Using the ALMA $^{12}$CO($J$ = 1-0) data, we have spatially resolved CO clouds along the southeastern edge of the SNR with an angular resolution of $\sim$1.8$"$ ($\sim$0.4 pc in the LMC). The molecular clouds show an expanding gas motion in the position-velocity diagram with an expansion velocity of $\sim5$ km s$^{-1}$. The spatial extent of the expanding shell is roughly similar to that of the SNR. We also find tiny molecular clumps in the directions of optical nebula knots. We present a possible scenario that N103B exploded in the wind-bubble formed by the accretion winds from the progenitor system, and is now interacting with the dense gas wall. This is consistent with a single-degenerate scenario.