Real-time evolution of a large-scale relativistic jet

Context. Astrophysical jets are ubiquitous in the Universe on all scales, but their large-scale dynamics and evolution in time are hard to observe since they usually develop at a very slow pace. Aims. We aim to obtain the first observational proof of the expected large-scale evolution and interaction with the environment in an astrophysical jet. Only jets from microquasars offer a chance to witness the real-time, full-jet evolution within a human lifetime, since they combine a 'short', few parsec length with relativistic velocities. Methods. The methodology of this work is based on a systematic recalibraton of interferometric radio observations of microquasars available in public archives. In particular, radio observations of the microquasar GRS 1758-258 over less than two decades have provided the most striking results. Results. Significant morphological variations in the extended jet structure of GRS 1758-258 are reported here that were previously missed. Its northern radio lobe underwent a major morphological variation that rendered the hotspot undetectable in 2001 and reappeared again in the following years. The reported changes confirm the Galactic nature of the source. We tentatively interpret them in terms of the growth of instabilities in the jet flow. There is also evidence of surrounding cocoon. These results can provide a testbed for models accounting for the evolution of jets and their interaction with the environment.Comment: 5 pages, 3 figures, 2 tables. Accepted for publication in Astronomy and Astrophysics Letter

The radio jets of SS 433 at millimetre wavelengths

Context. SS 433 is historically a well-known microquasar in the Galaxy that has been deeply studied during the four decades elapsed since its discovery. However, observations at very high radio frequencies with good angular resolution are still very scarce in the literature. The present paper tries to partially fill this gap using archival data of the source obtained with the Atacama Large Millimeter Array (ALMA). Aims. We aim to study the SS 433 jet properties at radio frequencies corresponding to millimetre wavelengths where the synchrotron emitting particles are expected to lose their energy much faster than at lower frequencies of centimetre wavelengths. Results. A resolved view of the SS 433 radio core and jets is presented. In addition to spectral index and magnetic field measurements, we are able to estimate the age of the oldest visible ejecta still radiating significantly at millimetre wavelengths. By combining our findings with those of previous authors at lower frequencies, we confirm that the energy loss of the radiating electrons is dominated by adiabatic expansion instead of synchrotron radiative losses. In addition, we find suggestive evidence for the previously proposed period of slowed expansion within the first months of the ejecta flow, needed to simultaneously match the radiative lifetime observed in the centimetre domain. Our results argue for the need for future coordinated millimetre and centimetre interferometric observations with good time sampling throughout the SS 433 precessional cycle to better understand energetic processes in stellar relativistic jets.Comment: 14 pages, 7 figures, Accepted for publication in Astronomy & Astrophysic

Aportación al conocimiento del ciclo biológico de Chromulina nevadensis

En este trabajo se amplía y se comenta la descripción de Chromulina nevadensis P.M. Sánchez. El estudio se realiza en una laguna oligotrófica de alta montaña (La Caldera), próxima a la laguna de Aguas Verdes, donde se obtuvo el material para su descripción original.Igualmente realizamos algunas consideraciones sobre el comportamiento mixotrófico de este taxon, ya conocido para otros miembros de las crisofíceas. Para finalizar describimos, por primera vez, la morfología a MEB de su estatosporaIn this paper we present data about enlargement of the original description of Chromulina nevadensis. This study has been carried out on an oligotrophic high mountain lake (La Caldera) close to the lake where it was described (Aguas Verdes). Also we make some consideration about the mixotrophy, a nutritional behavior previously knew for other chrysophyceae taza. Finally we study, by the first time, the morfology of its statospores with SEM

Aplicación de la impresión 3D en el diseño personalizado inclusivo

Trabajo presentado en: Jornada Fabricación Aditiva y sus aplicaciones en el ámbito educativo e industrial, Burgos, 11 de junio de 201