Using the XMM-Newton satellite and the Hubble Space Telescope (HST), astronomers made X-ray and near-infrared observations of a middle-aged pulsar known as PSR B1055-52. Results of the observation campaign published on the Preprints server arXivThis provides important information about the pulsar’s properties.

Pulsars are rotating neutron stars with strong magnetization that emit a beam of electromagnetic radiation. They often appear as short bursts of radio radiation; but some are also observed with optical, X-ray and gamma-ray telescopes.

While the distance to PSR B1055–52 is uncertain, preliminary studies suggest it is not 2,300 light-years from Earth. The PSR B1055–52 has a rotation period of 197 milliseconds, a rotational age of approximately 535,000 years, a rotational force of 30 decillion erg/sec, and a surface magnetic field of 1.1 TG.

PSR B1055–52 is a well-studied pulsar, but there is some disagreement about its X-ray spectral parameters and fluxes. That’s why a team of astronomers led by Bettina Posselt of the University of Oxford, England, decided to examine PSR B1055–52 with XMM-Newton and HST.

“Previous observations of midlife gamma-ray, X-ray, and radio pulsar B1055-52 showed several features, such as a suspicious change in X-ray flux and spectral parameters, a large excess of the predicted thermal component. Expansion of the Rayleigh-Jeans X-ray thermal spectrum. A possible double discontinuity in the ultraviolet (UV) spectrum over the ultraviolet (UV) spectrum and the non-thermal spectral component between the optical and X-ray bands, the researchers explained, in the XMM-Newton Observatory in X-rays and the Hubble Space Telescope in the near-infrared (NIR) range.

The study found that, based on a comparison between the 2000 observations and the new XMM-Newton observations in 2019, the long-term X-ray properties of PSR B1005-52 appear stable. Also, the possibility that the short-lived X-ray flux may not be completely eliminated by changes that occurred before or around 2012. Astronomers think a calibration problem with the 2012 Chandra observation may explain the discrepancies reported in previous studies.

The power spectral index for the PSR B1005-52 was measured to be -0.57 in the energy range of 3–10 keV, and the calculated power law slope was approximately -0.24 for a color index of 0.03 mag. It was noted that the power law components in the UV-optical-infrared and X-ray spectra have similar slopes and are neatly interconnected, indicating common acceleration and emission mechanisms.

Additionally, the X-ray spectrum of PSR B1005-52 is inconsistent with the pattern spectra of a neutron star atmosphere similar to other middle-aged pulsars. This could indicate the condensed surface of a neutron star, whose spectrum is probably closer to that of a black body. The new observations also allowed the researchers to precisely measure the accurate motion of PSR B1005-52, which could be important for estimating the kinematic age of this pulsar.

“In principle, the now well-known appropriate movement can be used to limit kinematic age and provides an independent age estimation superior to the rather uncertain characteristic age. Such information provides a more reliable comparison with other NS.” [нейтронними зірками]Besides theoretical predictions such as the cooling curves of NS,” the authors of the paper concluded.