We report striking changes in the broadband spectrum of the compact jet of the black hole transient MAXI J1836–194 over state transitions during its discovery outburst in 2011. A fading of the optical-infrared (IR) flux occurred as the source entered the hard-intermediate state, followed by a brightening as it returned to the hard state. The

We demonstrate in this work that it is possible to derive spectra of integrated absorption lines for any type stellar system using the GTC/OSIRIS Tunable Filters and a novel observing technique which allows for a reconstruction of the line profiles. The method has been successfully proven for the globular cluster system of VCC1261, a dwarf

Context. The derivation of the effective temperature of a star is a critical first step in a detailed spectroscopic analysis. Spectroscopic methods suffer from systematic errors related to model simplifications. Photometric methods may be more robust, but are exposed to the distortions caused by interstellar reddening. Direct methods are difficult

We report the discovery of a highly eccentric, double-lined spectroscopic binary star system (TYC 3010-1494-1), comprising two solar-type stars that we had initially identified as a single star with a brown dwarf companion. At the moderate resolving power of the MARVELS spectrograph and the spectrographs used for subsequent radial-velocity (RV)

We present the results of the analysis of the first black hole confirmed with GTC in the X-ray binary system XTE J1859+226. By combining optical photometry taken with the INT, WHT and NOT with long-slit spectroscopy with OSIRIS+GTC, we have obtained an orbital period of 6.58 h, a secondary star radial velocity amplitude of K_2=541±70 km s^-1 and an

Bars are strong drivers of secular evolution in disk galaxies. Bars themselves can evolve secularly through angular momentum transport, producing different boxy/peanut and X-shaped bulges. Our Milky Way is an example of a barred galaxy with a boxy bulge. We present a self-consistent N-body simulation of a barred galaxy which matches remarkably well