New X-ray supernova remnants in NGC 7793

This work focuses on the detection of X-ray supernova remnants (SNRs) in the galaxy NGC 7793 and the study of their properties. X-ray SNRs in galaxies beyond the Local Group are rare, mainly due to the limited sensitivity of current X-ray instruments. Additionally, their identification requires an optical counterpart, making incomplete optical identification methods an extra challenge. Detecting X-ray SNRs in other galaxies is crucial to understanding their feedback in different evolutionary phases and gaining insights into their local interstellar medium (ISM). In NGC 7793, only one X-ray SNR was previously known, while a recent study reported nearly 240 optical SNRs. The discovery of a new, larger optical SNR sample motivated a re-examination of the X-ray SNR population by comparing optical SNRs with X-ray sources. To identify X-ray SNRs, we utilised ̧handra’s spatial resolution and analyzed all available archival data of NGC 7793, totaling 229. 9 ks over 19 years. After data reduction, we performed source detection and analysis, searching for X-ray sources coinciding with optical SNRs. We also used (1. 1 Ms combined EPIC MOS) for a spectral analysis of the confirmed and candidate SNRs. We detected 58 X-ray sources down to an observed luminosity of ̊m ∼ 1. 5 erg, s^. Among them, five X-ray counterparts to optical SNRs were identified, all presenting soft emission (<1. 2 keV) with no short- or long-term variability. One corresponds to the previously known X-ray SNR, while four are newly detected. Spectral modelling of two SNRs shows thermal spectra exceeding 2. 5 million K, with strong O, VII, O, VIII, and Ne, IX emission lines. A correlation between density, X-ray luminosity, and source softness was observed. We also report X-ray emission from supernova 2008bk, refining its position, and suggest two candidate X-ray SNRs with soft, non-variable spectra, one resembling the identified X-ray SNRs.