Related papers: Solar-like oscillations in Procyon A
Cool main-sequence, sub-giant and red-giant stars all show solar-like oscillations, pulsations that are excited and intrinsically damped by near-surface convection. Many overtones are typically excited to observable amplitudes, giving a…
We present a spectrum of Sgr A* observed simultaneously on June 17, 2003 at wavelengths from 90 to 0.7 cm with the VLA. In the spectrum, we also include the measurements of Sgr A* observed on the same day with the GMRT at 49 cm, the SMA at…
We present deep total intensity and polarization observations of the Coma cluster at 1.4 and 6.6 GHz performed with the Sardinia Radio Telescope. By combining the single-dish 1.4 GHz data with archival Very Large Array observations we…
The radio spectra of main-sequence stars remain largely unconstrained due to the lack of observational data to inform stellar atmosphere models. As such, the dominant emission mechanisms at long wavelengths, how they vary with spectral…
We report observations of solar spicules at millimeter wavelengths (mm-$\lambda$) using the Atacama Large Millimeter/submillimeter Array (ALMA). These are supplemented by observations in optical (O), ultraviolet (UV) and extreme ultraviolet…
We report here multi-epoch, multi-frequency observations of the circular polarization in Sagittarius A*, the compact radio source in the Galactic Center. Data taken from the VLA archive indicate that the fractional circular polarization at…
Stochastically-triggered photospheric light variations reaching $\sim$$40$ mmag peak-to-valley amplitudes have been detected in the O8Iaf supergiant V973 Scorpii as the outcome of two months of high-precision time-resolved photometric…
In the present analysis of Procyon-A and Eta-Bootis, we use the local-wave formalism which, despite its lack of precision inherent to any semi-analytical method, uses directly the model profile without any modification when calculating the…
High-frequency waves (5 mHz to 20mHz) have previously been suggested as a source of energy accounting partial heating of the quiet solar atmosphere. The dynamics of previously detected high-frequency waves is analysed here. Image sequences…
Aims. With the Solar Optical Telescope on Hinode, we investigate the basic properties of high-degree solar oscillations observed at two levels in the solar atmosphere, in the G-band (formed in the photosphere) and in the Ca II H line…
The supermassive black hole Sagittarius A* (Sgr A*) exhibits temporal and spectral variability across the electromagnetic spectrum. However, variability at radio frequencies below ~ 5 GHz for timescales shorter than a day remains largely…
We present a three epoch survey for transient and variables in the extended Chandra Deep Field South at 5.5 GHz with the Australia Telescope Compact Array. A region covering $\sim$0.3 deg$^{2}$ was observed on timescales of 2.5 months and…
We report detection of oscillations in brightness temperature, size, and horizontal velocity of three small bright features in the chromosphere of a plage/enhanced-network region. The observations, which were taken with high temporal…
After reionization, emission in the 21 cm hyperfine transition provides a direct probe of neutral hydrogen distributed in galaxies. Different from galaxy redshift surveys, observation of baryon acoustic oscillations in the cumulative 21 cm…
We present the results of observations of the radio halo in the Coma galaxy cluster at 4.8 GHz performed with the Sardinia Radio Telescope. The radio halo in this cluster is detected for the first time at this frequency with a statistical…
A grid of stellar evolution models for Procyon A has been calculated. These models include the best physics available to us (including the latest opacities and equation of state) and are based on the revised astrometric mass of Girard et…
Spectra of the cellular photospheric flows are determined from full-disk Doppler velocity observations acquired by the Helioseismic and Magnetic Imager (HMI) instrument on the Solar Dynamics Observatory (SDO) spacecraft. Three different…
Fibrils in the solar chromosphere carry transverse oscillations as determined from non-spectroscopic imaging data. They are estimated to carry an energy flux of several $\mathrm{kW~m}^{-2}$, which is a significant fraction of the average…
The Rapid Oscillations in the Solar Atmosphere (ROSA) instrument reveals solar atmospheric fluctuations at high frequencies. Spectra of variations of the G-band intensity (IG) and CaII K-line intensity (IK) show correlated fluctuations…
Faraday rotation measurements of the solar corona made with the Very Large Array (VLA) at frequencies of 1465 and 1665 MHz are reported. The measurements were made along 20 lines of sight to 19 extragalactic radio sources in March and…