An exploratory study is made of the influence, during the equinoxes, of the interplanetary magnetic field (IMF) sector structure on the ionospheric F-region using ionosonde data from several equatorial stations for a 3-yr ...

Wave traveltime shifts in the vicinity of sunspots are typically interpreted as arising predominantly from magnetic fields, flows and local changes in sound speed. We show here that the suppression of granulation related ...

We investigated the ionosphere response to the two severe geomagnetic storms in the ascending phase of solar cycle 25 which occurred during the 23-24 March 2023 (SYM-Hmin = −169 nT) and 23-24 April 2023 (SYM-Hmin = −233 ...

We report high angular resolution observations of NGC 1333 IRAS 4A, a protostellar binary including A1 and A2, at 0.84 mm with the Atacama Large Millimeter/submillimeter Array. From the continuum observations, we suggest ...

The observation of intense gamma-ray line emission from the Orion complex, attributed by Bloemen et al. to de-excitation of cosmic-ray carbon and oxygen nuclei, has important implications for emission from Orion in the ...

Gamma-ray bursts (GRB) are the most luminous physical phenomena in the universe, consisting of flashes of gamma rays that last from seconds to hours. In this paper we look at possible alternate scenarios for both short and ...

The dynamical models for neutron star glitches and postglitch behaviour, and the information they yield on the crustal moment of inertia, are applied to a catalogue of neutron star models. The implications for neutron star ...

Angle-frequency coupling in scattering of polarized light on atoms is represented by the angle-dependent (AD) partial frequency redistribution (PRD) matrices. There are several lines in the linearly polarized solar spectrum, ...

Scattering on a multi-level atomic system has dominant contributions from resonance and Raman scattering. While initial and final levels are the same for resonance scattering, they are different for Raman scattering. The ...

The incidence of intranight optical variability (INOV) is known to differ significantly among different classes of powerful active galactic nuclei (AGN). A number of statistical methods have been employed in the literature ...