Aims: The fine-structure of the magnetic field in a sunspot penumbra in the upper chromosphere is to be explored and compared to that in the photosphere. Methods: Spectropolarimetric observations with high spatial resolution were recorded with the 1.5-m GREGOR telescope using the GREGOR Infrared Spectrograph (GRIS). The observed spectral domain

La formación y evolución de las galaxias son cuestiones cruciales aún sin responder en la Astrofísica moderna. Las poblaciones estelares resueltas ofrecen la posibilidad de estudiar las galaxias cercanas a través de sus estrellas individuales, proporcionando de esta manera un gran número de observables y restricciones a los modelos, que son

Context. Active regions are the most prominent manifestations of solar magnetic fields; their generation and dissipation are fundamental problems in solar physics. Light bridges are commonly present during sunspot decay, but a comprehensive picture of their role in the removal of the photospheric magnetic field is still lacking. Aims: We study the

For the first time, we explore the dynamics of the central region of a galaxy cluster within r 500 ∼ 600 h‑1 kpc from its center by combining optical and X-ray spectroscopy. We use (1) the caustic technique, which identifies the cluster substructures and their galaxy members with optical spectroscopic data, and (2) the X-ray redshift fitting

Until recently, only a handful of dusty, star-forming galaxies (DSFGs) were known at z > 4, most of them significantly amplified by gravitational lensing. Here, we have increased the number of such DSFGs substantially, selecting galaxies from the uniquely wide 250, 350, and 500 μm Herschel-ATLAS imaging survey on the basis of their extremely red