Seismicity induces ground vertical and horizontal displacements that could affect the image quality obtained by telescopes in a similar fashion than atmospheric turbulence. In this work, we study the effect of local seismicity relative to atmospheric turbulence upon the image quality of astronomical observations at El Teide observatory and Roque de

We discuss the effects of microlensing on the broad emission lines (BELs) of QSOs in the light of recent determinations of the size of the broad-line region (BLR) and its scaling with QSO luminosity. Microlensing by star-sized objects can produce significant amplifications in the BEL of some multiple-imaged QSOs, and could be very relevant for high

From observations of almost 500 red giant branch stars in 29 Galactic open and globular clusters, we have investigated the behavior of the infrared Ca II triplet (8498, 8542, and 8662 Å) in the age range 13 Gyr

We present subarcsecond resolution mid-infrared (mid-IR) photometry in the wavelength range from 8 to 20 μm of 18 Seyfert galaxies, reporting high spatial resolution nuclear fluxes for the entire sample. We construct spectral energy distributions (SEDs) that the active galactic nucleus (AGN) dominates, relatively uncontaminated by starlight, adding

We report on time series Hα profiles of the late B-type supergiant Rigel (beta Orionis A). Our observations indicate the presence of variable and asymmetric outflows and infalls of matter. We have recorded a blueshifted high-velocity absorption component in Hα almost simultaneously with Kaufer et al. The final part of this extraordinary event has

Eight low-resolution near-infrared spectra (0.8-2.4 μm) of 32522 Thereus were obtained on 2002 August 28 from 0:30 to 5:30 UT, covering more than half of its rotation period, with the 3.56 m Telescopio Nazionale Galileo (TNG) at El Roque de los Muchachos Observatory (ORM, Canary Islands, Spain). All the spectra are red, probably due to a mantle of