A new study of the supernova remnant G344.7-0.1 located in the vicinity of the unidentified TeV source HESS J1702-420

Abstract

Context. The identification of counterparts of dark gamma-ray sources adds greatly to our understanding of their underlying astrophysical processes. Aims. We investigate the physical properties of the supernova remnant (SNR) G344.7-0.1, to clarify whether it hosts a pulsar wind nebula (PWN), and the possible physical relationship between the SNR and the gamma-ray source HESS J1702-420. Methods. The research was carried out based on new high-resolution radio images produced from archival ATCA and VLA data in combination with X-ray archival XMM-Newton data. The ambient interstellar medium was investigated in HI, 12CO and mid IR (λ 24 μm) with data from the public SGPS, CfA CO and MIPSGAL surveys, respectively. Results. Based on the radio images and the comparison with X-ray and IR observations, we confirm that there is no PWN within G344.7-0.1; the observed emission highlights sites where the SN blast wave is encountering dense material. No radio counterpart is found for the X-ray object CXOU J170357.8-414302. The X-ray radiation completely fills in the interior of the SNR, being thermal in nature and originating in heated ejecta. From the spectral analysis it is inferred that G344.7-0.1 is the result of a core-collapse SN that exploded about 3000 yr ago. On the basis of HI absorption and emission we redetermined its distance in (6.3 ± 0.1) kpc. From the study of the surrounding gas, we conclude that G344.7-0.1 has evolved within an HI bubble created by the SN precursor. This bubble is, in turn, part of a larger HI/IR ring created by the stellar wind of prior-generation stars, about 2.6 × 106 yr ago. A second generation of stars formed in this compressed gas and about 3000 yr ago one of these stars exploded, creating the SNR G344.7-0.1. This study suggests that G344.7-0.1 and its turbulent environment is a plausible counterpart for HESS J1702-420. © 2011 ESO.