Related papers: Anomalous frequency shifts in the solar system
In the solar wind an equipartition of kinetic energy densities can be easily established between thermal and suprathermal electrons and the instability conditions are markedly altered by the interplay of these two populations. The new…
Spectral distortions of the Cosmic Microwave Background (CMB) offer the possibility of probing processes which occurred during the evolution of our Universe going back up to Z$\simeq 10^7$. Unfortunately all the attempts so far carried out…
The Sun may copiously produce hypothetical light particles such as axions or dark photons, a scenario which can be experimentally probed with so-called helioscopes. Here we investigate the impact of the angular and spectral distribution of…
We present a proof of concept on the coupling of radio astronomical receivers and spectrometers with chemical reactorsand the performances of the resulting setup for spectroscopy and chemical simulations in laboratory astrophysics. Several…
We consider the inverse problem of recovering the spherically symmetric sound speed, density and attenuation in the Sun from the observations of the acoustic field randomly excited by turbulent convection. We show that observations at two…
The solar chromosphere exhibits a variety of waves originating from the photosphere and deeper layers, causing oscillations at different heights with distinct frequencies. This study identifies and analyze Atmospheric Gravity Waves (AGWs)…
Using full-disk observations obtained with the Michelson Doppler Imager (MDI) on board the Solar and Heliospheric Observatory (SOHO) spacecraft, we present variations of the solar acoustic mode frequencies caused by the solar activity…
We search for signatures of high-frequency oscillations in the upper solar photosphere and low chromosphere in the context of acoustic heating of outer stellar atmospheres. We use ultraviolet image sequences of a quiet center-disk area from…
Fluctuations in the Galactic synchrotron emission can be traced by the angular power spectrum of radio maps at low multipoles. At frequencies below few GHz, large-scale anisotropies are mainly induced by magnetic field turbulence. By…
We explore the microwave anisotropies at large angular scales produced by the emission from cold and large dust grains, expected to exist in the outer parts of the Solar System, using a simple toy model for this diuse emission. Its…
We investigate the effects of atmospheric dispersion on observations of the Sun at the ever-higher spatial resolutions afforded by increased apertures and improved techniques. The problems induced by atmospheric refraction are particularly…
In collision-poor plasmas from space, e.g., solar wind, terrestrial magnetospheres, kinetic instabilities are expected to play a major role in constraining the temperature anisotropy of plasma particles, but a definitive answer can be given…
Solar limb and disc spicule quasi- periodic motions have been reported for a long time, strongly suggesting that they are oscillating. In order to clear up the origin and possibly explain some solar limb and disc spicule quasi-periodic…
Spatial maps of the high-pass frequency filtered time-averaged root-mean-squared (RMS) Doppler velocities tend to show substantial decrements within regions of strong field and curiously, randomly distributed patches of enhancement in the…
This paper presents an overview of the radiative transfer problem of calculating the spectral line intensity and polarization that emerges from a (generally magnetized) astrophysical plasma composed of atoms and molecules whose excitation…
The very nature of the solar chromosphere, its structuring and dynamics, remains far from being properly understood, in spite of intensive research. Here we point out the potential of chromospheric observations at millimeter wavelengths to…
The Sun and $\alpha$ Cen A and B are the nearest stars to us. Despite the general agreement between their models and seismic and non-seismic constraints, there are serious problems pertaining to their interior. The good agreement between…
The Simons Observatory (SO) is a new experiment that aims to measure the cosmic microwave background (CMB) in temperature and polarization. SO will measure the polarized sky over a large range of microwave frequencies and angular scales…
Anomalous redshifts of some galactic objects such as binary stars, early-type stars in the solar neighborhood, and O stars in a star clusters are discussed. It is shown that all these phenomena have a common characteristic, that is, the…
Implications of the recently discovered systematic abundance difference between the Sun and two collections of `solar twins' are discussed. The differences can be understood as an imprint on the abundances of the solar convection zone…