# X-ray and radio studies of SNR CTB 37B hosting the magnetar CXOU J171405.7-381031

## TL;DR

This study combines X-ray and radio observations to analyze the supernova remnant CTB 37B, revealing its morphology, spectral properties, and physical parameters, and suggesting it is a young remnant expanding in a low-density environment.

## Contribution

It provides a comprehensive multi-wavelength analysis of CTB 37B, including distance estimation, spectral modeling, and physical parameter derivation, which enhances understanding of its evolution and environment.

## Key findings

- Distance to SNR estimated at 9.8 kpc
- Remnant is approximately 6200 years old
- Shock velocity around 915 km/s

## Abstract

We present a Chandra and XMM-Newton study of the SNR CTB 37B, along with archival radio observations. In radio wavelengths, CTB 37B is an incomplete shell showing bright emission from the eastern side while the X-ray morphology shows diffuse emission from regions surrounding the magnetar CXOU J171405.7-381031. We used archival HI absorption measurements to constrain the distance to the remnant as 9.8+/-1.5 kpc. The X-ray spectrum of the remnant is described by a thermal model in the 1-5 keV energy range, with a temperature of 1.3+/-0.1 keV. The abundances from the spectral fits are consistent with being solar or sub-solar. A small region of diffuse emission is seen to the southern side of the remnant, best fitted by a nonthermal spectrum with an unusually hard photon index of 1.3+/-0.3. Assuming a distance of 9.8 kpc to the SNR, we infer a shock velocity of 915+/-70 km/s and explosion energy of (1.8+/-0.6)e50 ergs. The overall imaging and spectral properties of CTB 37B favor the interpretation of a young SNR (6200 yr) propagating in a low-density medium, under the assumption of a Sedov evolutionary phase.