Constraining the Equation of State of Neutron Stars through GRB X-Ray Plateaus

The unknown equation of state (EoS) of neutron stars (NSs) is puzzling because of rich non-perturbative effects of strong interaction there. A method to constrain the EoS by using the detected X-ray plateaus of gamma-ray bursts (GRBs) is proposed in this paper. Observations show some GRB X-ray plateaus may be powered by strongly magnetized millisecond NSs. The properties of these NSs should then satisfy: (i) the spin-down luminosity of these NSs should be brighter than the observed luminosity of the X-ray plateaus; (ii) the total rotational energy of these NSs should be larger than the total energy of the X-ray plateaus. Through the case study of GRB 170714A, the moment of inertia of NSs is constrained as $I>1.0\times 10^{45}\left ( \frac{P_{\rm cri}}{1\;\rm ms} \right )^{2} \;\rm g\cdot cm^{2}$, where $P_{\rm cri}$ is the critical rotational period that an NS can achieve. The constraint of the radii of NSs according to GRB 080607 is shown in Table 1.Comment: 6 pages, 2 figute, The Astrophysical Journal, 886:87, 2019 December 1, https://doi.org/10.3847/1538-4357/ab490

Infrared imaging - case studies and applications

Recent advancements in the manufacture of solid state detectors have led to significant improvements in the use and applications of infrared (IR) imaging. Compared with traditional imaging in visible light, infrared imaging has abilities to convey significant additional information. Applications in medicine require wavelengths in the range of 0.8 to 25 microns while metrology and astronomy, traditionally, require wavelengths in the range of 25 microns to 1 mm. In this study, infrared imaging has been used as a tool to characterize a variety of objects and systems. Some of these case studies have been considered under conditions of thermodynamic non-equilibrium. The results obtained are analyzed by considering the radiative properties of various materials

On the transition stage of pulsar pulsed radio emission and its potential association with radio pulsar nulling

While the precise mechanism of generating pulsed coherent radio emission from pulsars remains elusive, certain gap-invoking models (especially, the inner gap model) offer a comprehensive and plausible explanation for the genesis and termination of such emissions. However, the transition stage between the period of persistent radio emission and the period of radio quiet remains poorly understood, despite observations indicating that a radio pulsar in the pulse nulling state is undergoing the transition stage. In this study, we present a qualitative explanation for the elusive transition stage by modeling pulsar magnetospheres analytically as equivalent RC circuits based on the inner gap model. Our result indicates that, due to lengthy spin-down, older radio pulsars will gradually shift from the state of persistent radio emission to a certain type of pulse nulling state by delayed sparks within their inner gaps.Comment: 5 pages, 2 figures, ApJ accepte