arXiv subjects

Lucas G. Barão

Publications and source records attributed to Lucas G. Barão.

3 recordsLinked to original sources

arXiv2026

Spin-down changes in PSR B0540-69 induced by a drift of the magnetic axis

The dynamics of the solid crust + magnetic field lines of pulsars is a much debated issue, and remains unsettled after 50 years. Some pieces of evidence have emerged to complete and confirm theoretical calculations and expectations. We discuss in the present work an interpretation of the behavior of the ''Crab Twin'' pulsar PSR B0540-69 in terms of the evolution of the magnetic field/quakes, connecting the behavior of the braking index with the underlying platelet drift and sudden discontinuous rearrangement (fast-slip) and long-term ones (slow-slip events), suggested by analogy with existing theoretical picture observed in the Earth's crust. The relationship of this scenario with permanent torque-changing glitches seen in the Crab and other young pulsars, and a set of similar events in the same object and others is addressed. We conclude that this physical approach is in principle consistent with all these sudden events, and point out future work to clarify the whole picture.

astro-ph.HE↗

arXiv2024

Evolution of long-period compact radio sources driven by winds

We address in this work the nature and evolution of the long-period compact star sources, which has recently added several unexpected members. The central hypothesis is that particle winds drive their evolution, being an important factor for these relatively old sources. We show the consistency of this picture and remark some unsolved problems and caveats within it.

astro-ph.HE↗

arXiv2023

Mass Distribution and Maximum Mass of Neutron Stars: Effects of Orbital Inclination Angle

Matter at ultra-high densities finds a physical realization inside neutron stars. One key property is their maximum mass, which has far-reaching implications for astrophysics and the equation of state of ultra dense matter. In this work, we employ Bayesian analysis to scrutinize the mass distribution and maximum mass threshold of galactic neutron stars. We compare two distinct models to assess the impact of assuming a uniform distribution for the most important quantity, the cosine of orbital inclination angles ($i$), which has been a common practice in previous analyses. This prevailing assumption yields a maximum mass of $2.25$~$M_\odot$ (2.15--3.32~$M_\odot$ within $90\%$ confidence), with a strong peak around the maximum value. However, in the second model, which indirectly includes observational constraints of $i$, the analysis supports a mass limit of $2.56^{+0.87}_{-0.58}~M_\odot$ ($2σ$ uncertainty), a result that points in the same direction as some recent results gathered from gravitational wave observations, although their statistics are still limited. This work stresses the importance of an accurate treatment of orbital inclination angles, and contributes to the ongoing debate about the maximum neutron star mass, further emphasizing the critical role of uncertainties in the individual neutron star mass determinations.

astro-ph.HE↗