PSR J0030+0451 Mass and Radius from NICER Data and Implications for the Properties of Neutron Star Matter
Abstract
Neutron stars are not only of astrophysical interest, but are also of great interest to nuclear physicists because their attributes can be used to determine the properties of the dense matter in their cores. One of the most informative approaches for determining the equation of state (EoS) of this dense matter is to measure both a star's equatorial circumferential radius R e and its gravitational mass M. Here we report estimates of the mass and radius of the isolated 205.53 Hz millisecond pulsar PSR J0030+0451 obtained using a Bayesian inference approach to analyze its energy-dependent thermal X-ray waveform, which was observed using the Neutron Star Interior Composition Explorer (NICER). This approach is thought to be less subject to systematic errors than other approaches for estimating neutron star radii. We explored a variety of emission patterns on the stellar surface. Our best-fit model has three oval, uniform-temperature emitting spots and provides an excellent description of the pulse waveform observed using NICER. The radius and mass estimates given by this model are R_e 13.02_(-1.06)^(+1.24) km and M = 1.44_(-0.14)^(+0.15) M_⊙ (68%). The independent analysis reported in the companion paper by Riley et al. explores different emitting spot models, but finds spot shapes and locations and estimates of R_e and M that are consistent with those found in this work. We show that our measurements of R_e and M for PSR J0030+0451 improve the astrophysical constraints on the EoS of cold, catalyzed matter above nuclear saturation density.
Additional Information
© 2019. The American Astronomical Society. Received 2019 August 9; revised 2019 October 9; accepted 2019 October 24; published 2019 December 12. Focus on NICER Constraints on the Dense Matter Equation of State. This work was supported by NASA through the NICER mission and the Astrophysics Explorers Program. The authors acknowledge the University of Maryland supercomputing resources (http://hpcc.umd.edu) that were made available for conducting the research reported in this Letter. M.C.M. is grateful for the hospitality of the Kavli Institute for Theoretical Physics at the University of California, Santa Barbara, where part of this Letter was written. This Letter was therefore supported in part by the National Science Foundation under grant No. NSF PHY-1748958. M.C.M. was also supported by a Visiting Researcher position at Perimeter Institute for Theoretical Physics in the last stages of this project. W.C.G.H. appreciates the use of computer facilities at the Kavli Institute for Particle Astrophysics and Cosmology. J.M.L. acknowledges support from NASA through grant 80NSSC17K0554 and the U.S. DOE from grant DE-FG02-87ER40317. R.M.L. acknowledges the support of NASA through Hubble Fellowship Program grant HST-HF2-51440.001. The authors acknowledge the use of NASA's Astrophysics Data System (ADS) Bibliographic Services and the arXiv. Facility: NICER (Gendreau et al. 2016). Software: emcee (Foreman-Mackey et al. 2013), MultiNest (Feroz et al. 2009), Python and NumPy (Oliphant 2007), Matplotlib (Hunter 2007), Cython (Behnel et al. 2011), SuperMongo (https://www.astro.princeton.edu/~rhl/sm/sm.html).Attached Files
Published - Miller_2019_ApJL_887_L24.pdf
Accepted Version - 1912.05705.pdf
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Additional details
- Eprint ID
- 100290
- Resolver ID
- CaltechAUTHORS:20191213-105048030
- NASA Einstein Fellowship
- PHY-1748958
- NSF
- Perimeter Institute for Theoretical Physics
- 80NSSC17K0554
- NASA
- DE-FG02-87ER40317
- Department of Energy (DOE)
- HST-HF2-51440.001
- NASA Hubble Fellowship
- Created
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2019-12-16Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field