• FERMI-LAT
• glitches
• gravitational waves
• multi-messenger
• pulsars

Pulsars are among the most extreme astrophysical objects in the Galaxy. They are highly magnetized spinning neutron stars, characterized by pulsed periodic electromagnetic emission, which takes place at the expense of the rotational energy. Therefore, pulsars slow down in time, in a process generally referred to as pulsar braking. However, sudden deviations from this expected behavior have been observed and labeled with the name "glitches". Glitches are unpredictable events, supposedly caused by an abrupt redistribution of angular momentum within the crust of the neutron star, because of a non-uniform internal composition. Among the known pulsars, those emitting gamma-rays are of particular interest, because they are very young and energetic, and the study of their glitches can be very interesting. Moreover, since a glitch leads to a rearrangement of the pulsar interior, a dislocation of matter is most likely to occur too, causing a variation in the mass quadrupole moment of the star, with consequent emission of a gravitational wave signal (GW). However, this emission has not yet been detected by current GW detectors. In this work, we present a systematic analysis of gamma-ray glitches for a selection of radio-quiet pulsars, reported in the Fermi Third Pulsar Catalog (3PC), which is the result of more than 15 years of observation performed by the Fermi Large Area Telescope (Fermi-LAT). Furthermore, we select those glitches that occurred within LIGO-Virgo-KAGRA (LVK) observing runs, computing the corresponding expected GW strain amplitude. We decided to analyze the radio-quiet pulsars because they can reveal important information about the pulsar emission mechanisms and they permit a complementary insight on pulsar physics with respect to radio observations alone, also considering that Fermi-LAT permits continuous monitoring in the gamma-ray frequency band. After selecting 17 radio-quiet gamma-ray pulsars form the 3PC, we analyzed the Fermi-LAT data of each source, over a period spanning between August 4, 2008 and May 5, 2025. For each pulsar, we performed a periodicity search aimed at tracking the pulsar spin-down evolution, detecting glitches, and measuring their parameters. By plotting the spin frequency as a function of time, we confirmed the glitches already reported in the 3PC and we also discovered new uncataloged glitches. We selected all the glitches that occurred during one of the LVK observing runs and we computed their expected GW strain amplitude. These estimates are important to understand the potential of glitch detection by present and future GW detectors, and to provide useful input in order to develop new detection pipeline, selecting the best glitches to look for, in order to maximize the scientific output of the next multi-messenger investigations of pulsars.