Related papers: Where the granular flows bend
From the inversion of a time series of high resolution slit spectrograms obtained from the quiet sun, the spatial and temporal distribution of the thermodynamical quantities and the vertical flow velocity is derived as a function of…
In the past two decades, the complex nature of sunspots has been disclosed with high-resolution observations. One of the most important findings is the "uncombed" penumbral structure, where a more horizontal magnetic component carrying most…
Continuous observations of sunspot penumbrae with the Solar Optical Telescope aboard \textit{Hinode} clearly show that the outer boundary of the penumbra fluctuates around its averaged position. The penumbral outer boundary moves inward…
Plasma flow measurements in solar active region filaments are rare, particularly in the infrared and ultraviolet ranges that probe the chromosphere and transition region. In addition, previous studies generally focused on prominences and…
The O I 1355{\AA} spectral line is one of the only optically thin lines that are both routinely observed and thought to be formed in the chromosphere. We present analysis of a variety of observations of this line with the Interface Region…
Internetwork (IN) magnetic fields are highly dynamic, short-lived magnetic structures that populate the interior of supergranular cells. Since they emerge all over the Sun, these small-scale fields bring a substantial amount of flux, and…
Searches for small exoplanets around solar-type stars are limited by stellar physical variability. While chromospheric variability is well studied, observing, modeling. and understanding the much smaller fluctuations in photospheric…
Recent numerical simulations of sunspots suggest that overturning convection is responsible for the existence of penumbral filaments and the Evershed flow, but there is little observational evidence of this process. Here we carry out a…
A triplet of subordinate lines of Mg II exists in the region around the h&k lines. In solar spectra these lines are seen mostly in absorption, but in some cases can become emission lines. The aim of this work is to study the formation of…
We explore the weak lensing effects by ministructures in the line-of-sight in a quadruply lensed quasar MG0414+0534 that shows an anomaly in the flux-ratios. We find that the observed flux-ratio anomaly can be explained by a presence of…
Magnetic fields emerging from the Sun's interior carry information about physical processes of magnetic field generation and transport in the convection zone. Soon after appearance on the solar surface the magnetic flux gets concentrated in…
Emission-line variability studies have the potential to provide key information about the structures of the near-nuclear outflow regions of AGN. Here we present a VLT/Xshooter spectrum of the nucleus of the ULIRG F01004-2237 that was taken…
Ubiquitous small-scale vortices have recently been found in the lower atmosphere of the quiet Sun in state-of-the-art solar observations and in numerical simulations. We investigate the characteristics and temporal evolution of a…
Recent analysis revealed that supergranules (convection cells seen at the Sun's surface) are advected by the zonal flows at depths equal to the widths of the cells themselves. Here we probe the structure of the meridional circulation by…
We present near-infrared medium-resolution ($R \sim 875$) spectra of the microquasar GRS 1915+105 on 1997 August 13-15 UTC from the Hale 200-inch telescope. The spectra showed broad emission lines of He I (2.058 $\mu$m) and H I (2.166…
High-resolution time series of sunspots have been obtained with the Swedish 1m Solar Telescope between 2003 and 2006 at different locations on the solar disc. Proper motions in seven different active regions have been studied. The analysis…
Magnetic reconnection is the key mechanism for energy release in solar eruptions, where the high-temperature emission is the primary diagnostic for investigating the plasma properties during the reconnection process. Non-thermal broadening…
Twisting motions of different nature are observed in several layers of the solar atmosphere. Chromospheric sunspot whorls and rotation of sunspots or even higher up in the lower corona sigmoids are examples of the large scale twisted…
A high level of complex structure, or ``granularity'', has been observed in the distribution of infrared-obscuring material towards the Galactic Centre (GC), with a characteristic scale of 5arcsec - 15arcsec, corresponding to 0.2 - 0.6pc at…
We point out that luminous magnetic flares, thought to occur in standard AGN accretion disks, cannot be located much higher than few pressure scale heights above the disk. Using this fact, we estimate the fraction of the disk surface…