Optical and Infrared Observations of the X-ray source 1WGA J1713.4$-$3949 in the G347.3-0.5 SNR

TL;DR

This study uses deep optical and infrared observations to investigate the nature of the central compact object 1WGA J1713.4-3949 in the G347.3-0.5 supernova remnant, aiming to identify its counterpart and understand its properties.

Contribution

First deep multi-wavelength optical and IR observations of 1WGA J1713.4-3949, providing constraints on its possible counterparts and nature.

Findings

Detected faint candidate counterparts near the X-ray position.

None of the candidates can be confidently associated with the neutron star.

Faintest candidate's identification with the neutron star cannot be excluded.

Abstract

X-ray observations unveiled the existence of enigmatic point-like sources at the centre of young supernova remnants (SNRs). These sources, dubbed Central Compact Objects (CCOs), are thought to be neutron stars formed by the supernova explosion. However, their multi-wavelength phenomenology is surprisingly different from that of most young neutron stars.The aim of this work is to understand the nature of the CCO 1WGA J1713.4-3949 in the G347.3-0.5 SNR, through deep optical and IR observations, the first ever performed for this source.By exploiting its derived Chandra X-ray position we carried out optical (BVI) observations with the NTT and Adaptive Optics IR (JHKs) observations with the VLT. We detected two faint (I~23.5, I~24.3.) patchy objects in the NTT images, close to the Chandra error circle. They were clearly resolved in our VLT images which unveiled a total of six candidate counterparts (17.8<H<20.3) with quite red colours (H-Ks~0.6). If they are stars, none of them can be associated with 1WGA J1713.4-3949 for the most likely values of distance and hydrogen column density. The identification of the faintest candidate with the neutron star itself can not be firmly excluded, while the identification with a fallback disk is ruled out by its non-detection in the I band. No other candidates are detected down to B~26, V~26.2, I~24.7, H~21.3 and K~20.5. Our high-resolution IR imaging of unveiled a few objects close/within the Chandra X-ray position of 1WGA J1713.4-3949. However, at present none of them can be firmly identified as its likely counterpart.