2025ApJ...991...44L

Globular clusters (GCs) offer a unique environment for discovering and studying millisecond pulsars. In this paper, we present a multiepoch search and detailed timing analysis of millisecond pulsars in the GC M2, using the Five-hundred-meter Aperture Spherical radio Telescope. We have discovered two new binary millisecond pulsars in M2, designated M2F and M2G. We provide measurements of the emission properties of all known pulsars in M2, including their polarization profiles, rotation measures (RMs), flux densities, scintillation characteristics, and so forth. In particular, we report the first RM at the distance and direction of this cluster. Additionally, we report the first phase-coherent timing solutions for the M2 pulsars. From our Bayesian timing analysis, we have measured their spin and orbital parameters with high precision, including the advance of periastron for M2A and M2E indicating total system masses of 1.75(13) and 1.80(5) solar masses, respectively. Using archival data from the Hubble Space Telescope, we have identified an optical counterpart of M2C, which is likely the white dwarf companion of the pulsar. By combining results from optical and radio observations, we have reconstructed the binary evolution track of this system and estimated the cooling age of the companion to be approximately 10 Myr, making it the youngest white dwarf in any known GC binary pulsars. Furthermore, using the spin period derivatives of M2 pulsars, we have investigated the gravitational potential of the cluster and found that our results strongly support the latest central stellar velocity dispersion measurement in M2.