We present multi-wavelength analysis of 1LHAASO J1740+0948u and its surroundings including the pulsar wind nebula of middle-aged pulsar PSR J1740+1000. Although a dozen X-ray sources are found within the UHE emission site, careful analysis shows that they are unlikely to produce the observed UHE emission. The most likely particle accelerator is pulsar J1740+1000 which if offset by 13' north of the UHE source but appears to be connected to it by an extended feature seen in X-rays. For a plausible pulsar distance of 1.2 kpc, 1LHAASO J1740+0948u must be located about 5 pc away which requires rapid transport of electrons along the feature to avoid radiative losses. This poses several challenges for standard pulsar theory. Firstly, being produced $\lesssim$ 10 kyrs ago, particles must have been accelerated to the energy corresponding to a large fraction of the pulsar's full potential drop across the polar cap. Secondly, due to the lack of TeV emission extension toward the pulsar, particles must be accumulating in the UHE region. In this context, we discuss two possible scenarios: a tail filled with pulsar wind and confined by the bow-shock due to the fast pulsar's motion and an ISM filament filled by the most energetic pulsar wind particles escaping from the apex of the bow-shock.

The XMM-Newton observatory has accumulated a vast archive of over 17,000 X-ray observations over the last 25 years. However, the standard data processing pipelines may fail to detect certain types of transient X-ray sources due to their short-lived or dim nature. Identifying these transient sources is important for understanding the full range of temporal X-ray behaviour, as well as understanding the types of sources that could be routinely detected by future missions such as Athena. This work aims to reprocess XMM-Newton archival observations using newly developed dedicated software in order to identify neglected and missed transient X-ray sources that were not detected by the existing pipeline. We use a new approach that builds upon previous methodologies, by transforming event lists into data cubes, which are then searched for transient variability in short time windows. Our method enhances the detection capabilities in the Poisson regime by accounting for the statistical properties of sparse count rates, and allowing for transient search in previously discarded periods of high background activity. Our reprocessing efforts identified 32,247 variable sources at the 3-sigma level and 4,083 sources at the 5-sigma level in 12,926 XMM archival observations. We highlight four noteworthy sources: A candidate quasi-periodic eruption (QPE), a new magnetar candidate, a previously undetected Galactic hard X-ray burst and a possible X-ray counterpart to a Galactic radio pulsar. Our method demonstrates a new, fast, and effective way to process event list data from XMM-Newton, which is efficient in finding rapid outburst-like or eclipsing behaviour. This technique can be adapted for use with future telescopes, such as Athena, and can be generalised to other photon counting instruments operating in the low-count Poisson regime.