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PSR J0030+0451 Mass and Radius from NICER Data and Implications for the Properties of Neutron Star Matter

Miller, M. C. and Lamb, F. K. and Dittmann, A. J. and Bogdanov, S. and Arzoumanian, Z. and Gendreau, K. C. and Guillot, S. and Harding, A. K. and Ho, W. C. G. and Lattimer, J. M. and Ludlam, R. M. and Mahmoodifar, S. and Morsink, S. M. and Ray, P. S. and Strohmayer, T. E. and Wood, K. S. and Enoto, T. and Foster, R. and Okajima, T. and Prigozhin, G. and Soong, Y. (2019) PSR J0030+0451 Mass and Radius from NICER Data and Implications for the Properties of Neutron Star Matter. Astrophysical Journal Letters, 887 (1). Art. No. L24. ISSN 2041-8213.

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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.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Miller, M. C.0000-0002-2666-728X
Lamb, F. K.0000-0002-3862-7402
Dittmann, A. J.0000-0001-6157-6722
Bogdanov, S.0000-0002-9870-2742
Guillot, S.0000-0002-6449-106X
Harding, A. K.0000-0001-6119-859X
Ho, W. C. G.0000-0002-6089-6836
Lattimer, J. M.0000-0002-5907-4552
Ludlam, R. M.0000-0002-8961-939X
Mahmoodifar, S.0000-0003-2386-1359
Morsink, S. M.0000-0003-4357-0575
Ray, P. S.0000-0002-5297-5278
Strohmayer, T. E.0000-0001-7681-5845
Wood, K. S.0000-0002-7376-3151
Enoto, T.0000-0003-1244-3100
Foster, R.0000-0002-2731-9295
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 ( 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 (
Funding AgencyGrant Number
NASA Einstein FellowshipUNSPECIFIED
Perimeter Institute for Theoretical PhysicsUNSPECIFIED
Department of Energy (DOE)DE-FG02-87ER40317
NASA Hubble FellowshipHST-HF2-51440.001
Subject Keywords:X-ray sources ; Millisecond pulsars ; Neutron stars ; Neutron star cores
Issue or Number:1
Classification Code:Unified Astronomy Thesaurus concepts: X-ray sources (1822); Millisecond pulsars (1062); Neutron stars (1108); Neutron star cores (1107)
Record Number:CaltechAUTHORS:20191213-105048030
Persistent URL:
Official Citation:M. C. Miller et al 2019 ApJL 887 L24
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:100290
Deposited By: George Porter
Deposited On:16 Dec 2019 15:45
Last Modified:16 Dec 2019 15:45

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