This paper documents the 16th data release (DR16) from the Sloan Digital Sky Surveys (SDSS), the fourth and penultimate from the fourth phase (SDSS-IV). This is the first release of data from the Southern Hemisphere survey of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2); new data from APOGEE-2 North are also included

TEIDESAT is an initiative that was born in the University of La Laguna (Tenerife, Canary Islands), in December 2017, and that now involves up to 25 students, mainly from the University of La Laguna (ULL) and the University of Las Palmas de Gran Canaria (ULPGC), but that has extended widely, with students from universities in Madrid, Valencia

IGR J17091-3624 is a low-mass X-ray binary (LMXB), which received wide attention from the community thanks to its similarities with the bright black hole system GRS 1915+105. Both systems exhibit a wide range of highly structured X-ray variability during outburst, with time-scales from few seconds to tens of minutes, which make them unique in the

Stars with an external convective envelope have rotation periods that evolve as the square root of the age on the main sequence. This led to empirical "gyrochronology" relations, which should allow us to determine the age of a star from its surface rotation period. Recently, the exquisite Kepler data showed that there is a stalling of the magnetic

Besides the standard analysis based on mean properties, Surface Brightness Fluctuations (SBF) spectra provide an alternative way for studying stellar populations in galaxies. Metal-poor populations are predicted in galaxy formation models, but so far remain undetected beyond the Local Group. The SBF spectra have the potential to unveil these metal

We investigate the physical nature and origin of the gamma-ray emission from the extended source HESS J1841-055 observed at TeV and GeV energies. We observed HESS J1841-055 at TeV energies for a total effective time of 43 h with the MAGIC telescopes, in 2012 and 2013. Additionally, we analysed the GeV counterpart making use of about 10 yr of Fermi