arXiv subjects

Innocent Okwudili Eya

Publications and source records attributed to Innocent Okwudili Eya.

3 recordsLinked to original sources

arXiv2025

The Influential Roles of Gravity, Turbulence, and Magnetic Fields in Shaping the Physical Evolution of Dense Massive Clumps

We explore the roles of the three competitors, namely, gravity, turbulence, and magnetic fields, in controlling star formation (SF) within dense, massive clumps identified in the ATLASGAL survey. By examining scaling relations, virial parameters, and turbulent energy spectra, we evaluate the dynamical state of these clumps. We observe a weak velocity dispersion-size relation (sigma proportional to L^0.11), which is much shallower than the classical Larson-like relations, suggesting that turbulence does not mainly drive internal dynamics. The turbulent energy spectrum, E(k) proportional to k^-1.21, is also less steep than what is expected for both incompressible and compressible turbulence. We equally observe a decreasing trend in the virial parameter with increasing mass (alpha_vir proportional to M^-0.37), indicating that more massive clumps are increasingly gravitationally bound. These trends indicate an increasing relative dominance of gravity over turbulence at smaller scales, aligning with multiscale collapse scenarios; however, the absolute energy balance remains unquantifiable with the current data. Although magnetic fields are not directly measured, their potential influence is considered in the interpretation of pressure balance and dynamical support. Our findings imply that gravitational processes appear to primarily regulate the structure and evolution of massive clumps.

astro-ph.GA↗

arXiv2024

Pulsar glitch activities: the spin parameters approach

Glitch activity refers to the mean increase in pulsar spin frequency per year due to rotational glitches. It is an important tool for studying super-nuclear matter using neutron star interiors as templates. Glitch events are typically observed in the spin frequency ($ν$) and frequency derivative ($\dotν$) of pulsars. The rate of glitch recurrence decreases as the pulsar ages, and the activity parameter is usually measured by linear regression of cumulative glitches over a given period. This method is effective for pulsars with multiple regular glitch events. However, due to the scarcity of glitch events and the difficulty of monitoring all known pulsars, only a few have multiple records of glitch events. This limits the use of the activity parameter in studying neutron star interiors with multiple pulsars. In this study, we examined the relationship between the activity parameters and pulsar spin parameters (spin frequency, frequency derivative, and pulsar characteristic age). We found that a quadratic function provides a better fit for the relationship between activity parameters and spin parameters than the commonly used linear functions. Using this information, we were able to estimate the activity parameters of other pulsars that do not have records of glitches. Our analysis shows that the relationship between the estimated activity parameters and pulsar spin parameters is consistent with that of the observed activity parameters in the ensemble of pulsars.

astro-ph.HE↗

arXiv2020

Microglitches in radio pulsars: the role of strange nuggets

Strange Nuggets are believed to be among the relics of the early universe. They appear as dark matter due to their low charge-to-mass ratio. Their distribution is believed to be the same as that of dark matter. As such, they could be accreted by high magnetic field objects and their collisions with pulsars are inevitable. Pulsar glitches are commonly seen as sudden spin-ups in pulsar frequency. It is still an open debate with regard to mechanisms giving rise to such a phenomenon. However, there is a class of sudden changes in pulsar spin frequency known as microglitches. These event are characterized by sudden small change in pulsar spin frequency ($ δν/ν\approx \pm 10^{-9}$). Clearly, the negative signature seen in some of the events is inconsistent with the known glitch mechanisms. In this analysis, we suggest that accretion of strange nuggets with pulsars could readily give rise to microglitch events. The signature of the events depends on the energy of the strange nuggets and line of interaction.

astro-ph.HE↗