Speaker
Description
The quest for the maximum mass possibly achieved by a neutron star (NS) is an old venerable subject. 50+ years ago very low values were considered, mainly put forward from a theoretical point of view. The discovery of the binary pulsar PSR 1913+16, and later on, similar systems, allowed the determination of the mass with two or more decimal places, leading to the (now proved wrong) idea of a “canonical” value of $1.4 M_{\odot}$. However, progressively higher values were reported and confirmed. Today the consensus is that at least $2 M_{\odot}$ neutron star exist. Higher values are not only possible, but actually published by many authors. We shall discuss in this presentation how the existing sample of 104 measured NS masses leads to infer a maximum mass of $\sim 2.5-2.6 M_{\odot}$, using Bayesian techniques with an without a cutoff (related to the very end of a theoretical sequence), and a few important individual cases which may indicate that the maximum mass may be well above the $2.2 M_{\odot}$ ballpark generally accepted. These cases include PSR J0952-0607, PSR J1748-2021B in NGC 6440, 4U 1820-30 and the GW events in which enigmatic low-mass members have been seen.
