Speaker
Description
Understanding the birthrate of magnetars, highly magnetized neutron stars, is essential for constraining their role in high-energy astrophysical phenomena such as gamma-ray bursts (GRBs) and fast radio bursts (FRBs). In this talk, we aim to estimate the magnetar birthrate in the Milky Way by analyzing the Galactic population of observed young neutron stars. In this sample, magnetars appear to make up approximately 35% of this population, with the remainder classified as central compact objects (CCOs) or rotation-powered pulsars (RPPs). However, this percentage may be significantly affected by selection effects and observational biases. An important bias in defining a sample of young pulsars is the discrepancy between a neutron star’s characteristic age and its true age, particularly relevant for young neutron stars with low magnetic fields, which tend to appear much older than they actually are. Moreover the beamed nature of pulsar radio emission, causes many neutron stars to go undetected because their radio beams do not intersect our line of sight. These effects likely lead to an underrepresentation of pulsars in the observed young neutron star population. To investigate these biases, we collect a sample of nearby supernova remnants (SNRs) associated with neutron stars. We then model the spatial distribution and dynamical evolution of SNRs in the Galaxy to determine how many are required to reproduce the observed number in the Solar neighborhood. This enables us to estimate a lower limit for the Galactic core-collapse supernova rate. By combining this information with pulsar population synthesis models, we estimate the expected number of young pulsars, correcting for both age and beaming-related biases. This allows us to refine the inferred fraction of magnetars among the young neutron star population. The resulting magnetar birthrate provides an independent constraint that complements estimates based solely on population synthesis, offering new insights into the connection between strongly magnetized neutron stars and the high-energy and radio transient sky.
