Top: comparison of the number of X-ray photons from 2XMMi J181928.8−145202 within the 0.5–2.6 keV energy range from the PN detector only that are coincident with a radio pulse within a given search window. X-ray photons coincident with the radio pulses are represented by diamonds and a solid line while the results of 10 ⁴ simulations are represented by the boxes (mean coincident photons of the simulations), vertical bars (standard deviation of coincident photons of the simulations), and the dotted line. Middle: the difference between the number of coincident photons for each window size in the data and the mean of the simulations. Bottom: as in the middle plot, normalized by the standard deviation of the simulations. Here the horizontal dotted line indicates one standard deviation of the simulated random sets.