2024/11/05 by Pacholski, Dominik P., Arrigoni, Edoardo, Mereghetti, Sandro +1
#Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE)
paper · doi:10.48550/arxiv.2411.03235
Giant flares from magnetars can reach, for a fraction of a second, luminosities greater than 1047 erg s-1 in the hard X-ray/soft γ-ray range. This makes them visible at distances of several megaparsecs. However, at extragalactic distances (farther than the Magellanic Clouds) they are difficult to distinguish from the short γ-ray bursts, which occur much more frequently. Since magnetars are young neutron stars, nearby galaxies with a high rate of star formation are optimal targets to search for magnetar giant flares (MGFs). Here we report the results of a search for MGFs in observations of the Virgo cluster and in a small sample of nearby galaxies obtained with the IBIS instrument on the INTEGRAL satellite. From the currently known MGF sample we find that their energy distribution is well described by a power law with slope γ=2 (with 90% c.l. interval [1.7-2.2]). From the lack of detections in this extensive data set (besides 231115A in M82) we derive a 90% c.l. upper limit on the rate of MGF with E>3×1045 erg of ∼2×10-3 yr-1 per magnetar and a lower limit of R(E)>∼4×10-4 yr-1 magnetar-1 for E<1045 erg.