"X-ray heartbeats from the nuclei of galaxies"

X-ray Quasi-Periodic Eruptions (QPEs) are the latest and perhaps the most peculiar addition to the zoo of extragalactic transients. They are high-amplitude bursts of X-ray radiation recurring every several hours and originating near the central black holes in galactic nuclei of low-mass galaxies. So far, only a handful of such events has been found, although with rising interest in the broader community given their observational and theoretical connection with tidal disruption events and, possibly, low-frequency gravitational wave sources. Some of the latest models suggest that these eruptions are triggered by extreme mass ratio inspirals (EMRIs), in which the secondary stellar body interacts with the accretion flow of the primary massive black hole. I will outline the observational properties of QPE sources and the latest insights from theoretical models, including their tantalizing connection with LISA EMRis.