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

dc.contributor.authori Bernadich, Miquel Colom
dc.contributor.authorSerylak, Maciej
dc.contributor.authorKrishnan, Vivek Venkatraman
dc.date.accessioned2025-01-22T06:49:27Z
dc.date.available2025-01-22T06:49:27Z
dc.date.issued2024
dc.description.abstractPSR 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 of 3.33 < β < 3.62, and a mean flux density of 0.53−0.62 mJy at 1 GHz with a steep spectral index of 2.06 < α < 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 [Formula Presented], and a Shapiro delay with an orthometric amplitude of h3 = 3.6 ± 0.5 µs and an orthometric ratio of ς = 0.85 ± 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 [Formula Presented], and 77.5 < i/deg < 80.3. We also constrain the longitude of ascending node to either Ωa = 266 ± 78 deg or Ωa = 86 ± 78 deg. We argue against a neutron star nature of the companion based on the very low orbital eccentric of the system (e = 1.15 × 10−3), and instead classify the companion of PSR J1227−6208 as a rare, massive ONeMg white dwarf close to the Chandrasekhar limit.
dc.identifier.citationi Bernadich, M.C., Krishnan, V.V., Champion, D.J., Freire, P.C., Kramer, M., Tauris, T.M., Bailes, M., Ridolfi, A., Lower, M.E. and Serylak, M., 2024. PSR J1227− 6208 and its massive white dwarf companion: Pulsar emission analysis, timing update, and mass measurements. Astronomy & Astrophysics, 690, p.A253.
dc.identifier.urihttps://doi.org/10.1051/0004-6361/202450724
dc.identifier.urihttps://hdl.handle.net/10566/19892
dc.language.isoen
dc.publisherEDP Sciences
dc.subjectBinaries
dc.subjectStars: evolution
dc.subjectStars: fundamental parameters
dc.subjectWhite dwarfs
dc.subjectStars: neutron
dc.titlePSR J1227−6208 and its massive white dwarf companion: pulsar emission analysis, timing update, and mass measurements
dc.typeArticle

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