PSR J1227$-$6208 and its massive white dwarf companion: pulsar emission analysis, timing update and mass measurements

Abstract

PSR J1227$-$6208 is a 34.53-ms recycled pulsar with a massive companion. This system has long been suspected to belong to the emerging class of massive recycled pulsar-ONeMg white dwarf systems such as PSR J2222$-$0137, PSR J1528$-$3146 and J1439$-$5501. Here we present an updated emission and timing analysis with more than 11 years of combined Parkes and MeerKAT data, including 19 hours of high-frequency data from the newly installed MeerKAT S-band receivers. We measure a scattering timescale of 1.22 ms at 1 GHz with a flat scattering index 3.33<$\beta$<3.62, and a mean flux density of 0.53-0.62 mJy at 1 GHz with a steep spectral index 2.06<$\alpha$<2.35. Around 15% of the emission is linearly and circularly polarised, but the polarisation angle does not follow the rotating vector model. Thanks to the sensitivity of MeerKAT, we successfully measure a rate of periastron advance of 0.0171(11) deg/yr, and a Shapiro delay with an orthometric amplitude of 3.6$\pm$0.5 $\mu$s and an orthometric shape of 0.85$\pm$0.05. The main source of uncertainty in our timing analysis is chromatic correlated dispersion measure noise, which we model as a power law in the Fourier space thanks to the large frequency coverage provided by the Parkes UWL receiver. Assuming general relativity and accounting for the measurements across all the implemented timing noise models, the total mass, companion mass, pulsar mass and inclination angle are constrained at 2.3<Mt/$M_{\odot }$<3.2, 1.21<Mc/$M_{\odot }$<1.47, 1.16<Mp/$M_{\odot }$<1.69 and 77.5<i/deg<80.3. We also constrain the longitude of ascending node to either 266$\pm$78 deg or 86$\pm$78 deg. We argue against a neutron star nature of the companion based on the very low orbital eccentric of the system (e=1.15e-3), and instead classify the companion of PSR J1227-6208 as a rare, massive ONeMg white dwarf close to the Chandrasekhar limit.

Paper accepted for publication at Astronomy & Astrophysics. Main text: 17 pages, 8 figures. Appendices: 3 pages, 5 figures

References in corpus (32)

• The Gaia mission
• Gaia Data Release 3: Summary of the content and survey properties
• TEMPO2, a new pulsar timing package. I: Overview
• The mass distribution and gravitational potential of the Milky Way
• PSRCHIVE and PSRFITS An Open Approach to Radio Pulsar Data Storage and Analysis
• Refined Mass and Geometric Measurements of the High-Mass PSR J0740+6620
• An Ultraluminous X-ray Source Powered by An Accreting Neutron Star
• Formation of Double Neutron Star Systems
• Tempo2, a new pulsar timing package. II: The timing model and precision estimates
• The Parkes multibeam pulsar survey: VI. Discovery and timing of 142 pulsars and a Galactic population analysis
• Super-critically accreting stellar-mass black holes as ultraluminous X-ray sources
• An accreting pulsar with extreme properties drives an ultraluminous x-ray source in NGC 5907
• Formation of millisecond pulsars with CO white dwarf companions - II. Accretion, spin-up, true ages and comparison to MSPs with He white dwarf companions
• On measuring the gravitational-wave background using Pulsar Timing Arrays
• A highly magnetised and rapidly rotating white dwarf as small as the Moon
• Constraining the dense matter equation-of-state with radio pulsars
• Closing a spontaneous-scalarization window with binary pulsars
• An ultra-massive white dwarf with a mixed hydrogen-carbon atmosphere as a likely merger remnant
• PSR J2222--0137. I. Improved physical parameters for the system
• Discovery of Five Recycled Pulsars in a High Galactic Latitude Survey
• The Relativistic Binary Programme on MeerKAT: Science objectives and first results
• A 1.05 $M_{\odot }$ Companion to PSR J2222-0137: The Coolest Known White Dwarf?
• Discovery of a hot ultramassive rapidly rotating DBA White Dwarf
• The Thousand-Pulsar-Array programme on MeerKAT -- V. Scattering analysis of single-component pulsars
• The High Time Resolution Universe Survey - XI. Discovery of five recycled pulsars and the optical detectability of survey white dwarf companions
• FAST early pulsar discoveries: Effelsberg follow-up
• The LOFAR Tied-Array All-Sky Survey: Timing of 21 pulsars including the first binary pulsar discovered with LOFAR
• Searches for Shapiro delay in seven binary pulsars using the MeerKAT telescope
• A precise mass measurement of PSR J2045+3633
• Optical Detection of Two Intermediate Mass Binary Pulsar Companions
• On the Chandrasekhar Limit in Generalized Uncertainty Principles
• Relativistic effects in a mildly recycled pulsar binary: PSR J1952+2630

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• The FAST Galactic Plane Pulsar Snapshot Survey: VII. Six millisecond pulsars in compact orbits with massive white dwarf companions