arXiv subjects

M. Rah

Publications and source records attributed to M. Rah.

3 recordsLinked to original sources

arXiv2026

Dust and Ices in the SNR

The presence of dust in supernova remnants (SNRs) is confirmed by extensive infrared data from observatories such as Spitzer, Herschel, and JWST, alongside theoretical models of dust formation. This study explores the existence of dust and ices, particularly water ice via 62 {\mu}m in SNRs such as the Crab Nebula and N49, using observational data and preliminary modeling with Cloudy. Observations suggest that water ice may be present in IC 443 and possibly other remnants, though the 63 {\mu}m band could also indicate [OI] emission. Theoretical models indicate that water ice could survive under certain conditions in SNRs, with densities and temperatures analyzed. Further observations and refined simulations are needed to confirm these findings.

astro-ph.HE↗

arXiv2026

Dynamical Preconditions for Ice Formation in Supernova Remnant and Cloud Interactions: A 2D MHD Study

Water ice has been detected in several supernova remnants despite the strong heating and radiation in these environments. This challenges standard expectations for dust survival. Using two dimensional magnetohydrodynamic simulations, we study how a supernova shock interacts with a dense interstellar cloud. The simulations show that the shock naturally compresses the cloud into dense structures similar to those inferred in well known remnants. Although temperatures remain high in the adiabatic phase, simple considerations indicate that cooling would act quickly once included. These results suggest that shock cloud interactions create the physical conditions needed for water ice to form. Future work including radiative cooling and grain surface chemistry will allow direct modelling of ice growth in these compressed regions.

astro-ph.HE↗

arXiv2026

Pulsars and Millisecond Pulsars III: Tracing Compact Object Dynamics in Globular Clusters with NBODY6++GPU

Neutron stars in globular clusters follow complex evolutionary pathways shaped by binary interactions, mass transfer, and dynamical exchanges. Direct N-body simulations such as NBODY6++GPU successfully model stellar dynamics and compact object formation, but they usually do not track pulsar spin evolution or magnetic field decay explicitly. Building on Papers I and II of this series, we identify this gap and present a case study from an existing simulation with N = 105000 particles, showing how a neutron star forms and evolves for 200 Myr without any pulsar-physics tracking. We compare this situation with recent implementations and outline a seven-scenario framework that includes magnetic dipole spin-down, exponential magnetic field decay, environmental torques, accretion-driven spin-up, gravitational-wave emission, and merger-driven evolution. As an example, the neutron star we label Pulsar973 forms at t = 800 Myr with a post-supernova mass of 5.35 solar masses and evolves to 2.52 solar masses by t = 1000 Myr, but still lacks period P, period derivative Pdot, magnetic field B, and scenario classification. We provide mathematical formulations and specific integration points within NBODY6++GPU (Hermite scheme, Ahmad-Cohen neighbors, KS regularization, and BSE stellar evolution) to enable scenario-based pulsar evolution within direct N-body simulations.

astro-ph.HE↗