| Abstrakt: |
We present refined neutron star masses measured in an Arecibo observing campaign of two binary radio pulsars, and we summarize the masses of the binary radio pulsar population. For PSR J0621+1002, we find the relativistic rate of advance of periastron to be ω = 0.0105±0.0002° yr-1, implying a total system mass (pulsar plus companion) of m1+m2 = 2.37±0.12 M⊙. Combined with the non-detection of Shapiro delay and an assumption that the companion star is a white dwarf, we constrain the mass of this pulsar to be m1 = 1.70-0.17+0.10 M⊙ (68% confidence), in agreement with previous measurements of this pulsar, but with higher precision. For PSR 0751+1807, we find the rate of orbital decay due to emission of gravitational radiation to be Pb = -(3.1±0.5)×10-14. Combining this with detection of Shapiro delay yields a pulsar mass of 1.26±0.14 M⊙ (68% confidence), much smaller than the previously reported value of 2.1±0.2 M⊙. We discuss the reason for this discrepancy. We present a summary of masses if pulsars in the Galactic disk measured via relativistic timing. We find recycled pulsars in neutron star–neutron star binaries to be about 0.05 M⊙ more massive than their unrecycled counterparts, and we find recycled pulsar in neutron star–white dwarf binaries to be about 0.20 M⊙ more massive than unrecycled pulsars. However, we caution against over-interpretation of these numbers. There is a significant spread in the distribution of masses measured in neutron star–neutron star binaries, and there are large uncertainties in masses measured in neutron star–white dwarf binaries, so these values must be considered tentative. [ABSTRACT FROM AUTHOR] |
