Astrometric configuration of J202040−621509. All images are centred on the optical position of the new quasar J202040−621509 and have sizes 100″ × 100″. Left panel: Broadband (0.5−7 keV) Chandra image. Chandra sources detected with 30″ (black, dashed circle) of the quasar coordinates with wavdetect are marked in red. The centroid of 1eRASS J202039.8−621525 catalogue detection is marked by a green triangle. The contours were obtained from the smoothed eRASS:4 0.5−7 keV image. Central panel: DES DR2 z-band image. Circular coloured markers denote counterpart candidates for 1eRASS J202039.8−621525 from the DESI Legacy Survey catalogue. They are colour-coded according to their relative probability p_i of being the best counterpart. The DESI Legacy Survey source with the highest p_i is spatially co-incident with the quasar coordinates. Right panel: CatWISE 2020 W1 image. Among the Chandra and eROSITA X-ray detections, only the quasar is unambiguously detected.