A NICER View of the Massive Pulsar PSR J0740+6620 Informed by Radio Timing and XMM-Newton Spectroscopy

We report on Bayesian estimation of the radius, mass, and hot surface regions of the massive millisecond pulsar PSR J0740+6620, conditional on pulse-profile modeling of Neutron Star Interior Composition Explorer X-ray Timing Instrument event data. We condition on informative pulsar mass, distance, a...

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Published inAstrophysical journal. Letters Vol. 918; no. 2; p. L27
Main Authors Riley, Thomas E., Watts, Anna L., Ray, Paul S., Bogdanov, Slavko, Guillot, Sebastien, Morsink, Sharon M., Bilous, Anna V., Arzoumanian, Zaven, Choudhury, Devarshi, Deneva, Julia S., Gendreau, Keith C., Harding, Alice K., Ho, Wynn C. G., Lattimer, James M., Loewenstein, Michael, Ludlam, Renee M., Markwardt, Craig B., Okajima, Takashi, Prescod-Weinstein, Chanda, Remillard, Ronald A., Wolff, Michael T., Fonseca, Emmanuel, Cromartie, H. Thankful, Kerr, Matthew, Pennucci, Timothy T., Parthasarathy, Aditya, Ransom, Scott, Stairs, Ingrid, Guillemot, Lucas, Cognard, Ismael
Format Journal Article
LanguageEnglish
Published Goddard Space Flight Center The American Astronomical Society 01.09.2021
IOP Publishing
Bristol : IOP Publishing
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Summary:We report on Bayesian estimation of the radius, mass, and hot surface regions of the massive millisecond pulsar PSR J0740+6620, conditional on pulse-profile modeling of Neutron Star Interior Composition Explorer X-ray Timing Instrument event data. We condition on informative pulsar mass, distance, and orbital inclination priors derived from the joint North American Nanohertz Observatory for Gravitational Waves and Canadian Hydrogen Intensity Mapping Experiment/Pulsar wideband radio timing measurements of Fonseca et al. We use XMM-Newton European Photon Imaging Camera spectroscopic event data to inform our X-ray likelihood function. The prior support of the pulsar radius is truncated at 16 km to ensure coverage of current dense matter models. We assume conservative priors on instrument calibration uncertainty. We constrain the equatorial radius and mass of PSR J0740+6620 to be-+12.390.981.30km and-+2.0720.0660.067Me respectively, each reported as the posterior credible interval bounded by the 16% and 84% quantiles, conditional on surface hot regions that are non-overlapping spherical caps of fully ionized hydrogen atmosphere with uniform effective temperature; a posteriori, the temperature is=-+TlogK5.99100.060.05([])for each hot region. All software for the X-ray modeling framework is open-source and all data, model, and sample information is publicly available, including analysis notebooks and model modules in the Python language. Our marginal likelihood function of mass and equatorial radius is proportional to the marginal joint posterior density of those parameters(within the prior support)and can thus be computed from the posterior samples.
Bibliography:AAS31658
GSFC
Goddard Space Flight Center
FG02-87ER40317
USDOE Office of Science (SC), Nuclear Physics (NP)
ISSN:2041-8205
2041-8213
DOI:10.3847/2041-8213/ac0a81