GTC Spectra of z ~ 2.3 Quasars: Comparison with Local Luminosity Analogues

[Abridged] Context: The advent of 8-10m class telescopes makes possible for the first time detailed comparison of quasars with similar luminosity and very different redshifts. Aims: A search for z-dependent gradients in line emission diagnostics and derived physical properties by comparing, in a narrow bolometric luminosity range (log L ~ 46.1 +/- 0.4 [\ergss]), some of the most luminous local (z < 0.6) quasars with some of the lowest luminosity sources yet found at redshift z = 2.1 ~ 2.5. Method: Spectra for 22 high z sources were obtained with the 10.4m Gran Telescopio Canarias (GTC) while the HST (largely FOS) archive provides a low redshift control sample. Comparison is made in the context of the 4D Eigenvector 1 formalism meaning that we divide both source samples into high accreting Population A and low accreting Population B sources. Results: CIV 1549 shows very similar properties at both redshifts confirming at high redshift the CIV profile differences between Pop. A and B that are well established in local quasars. The CIV blueshift that appears quasi- ubiquitous in higher L sources is found in only half (Pop. A) of quasars observed in both of our samples. A CIV evolutionary Baldwin effect is certainly disfavored. We find evidence for lower metallicity in the GTC sample that may point toward a gradient with z. No evidence for a gradient in black hole mass or Eddington ratio is found. Conclusions: Spectroscopic differences established at low redshift are also present in much higher redshift quasars. Given that our samples involve sources with very similar luminosity the evidence for a systematic metallicity decrease, if real, points toward an evolutionary effect. Our samples appear representative of a slow evolving quasar population likely present at all redshifts.Comment: To appear in Astronomy & Astrophysic

Prueba de habilidades practicas CCNP

La cuarta revolución industrial requiere de grandes manejos de información, las nuevas tecnologías de información cada vez aumentan la infraestructura de comunicaciones y redes de transmisión de datos, con diferentes tipologías y tipos de conexión o cableado. Es por este motivo la necesidad de profundizar mediante la plataforma Cisco, permite realizar comprensión de material teórico y práctico en la construcción, programación, conexión de redes LAN/WAN por medio de diferentes laboratorios remotos como Packet Tracer, GNS3, Smart LAB.The fourth industrial revolution requires great information management, new information technologies increasingly increase the communications infrastructure and data transmission networks, with different typologies and types of connection or wiring. It is for this reason the need to deepen through the Cisco platform, allows understanding of theoretical and practical material in the construction, programming, connection of LAN / WAN networks through different remote laboratories such as Packet Tracer, GNS3, Smart LAB

Hernando Domínguez Camargo (1606 - 1659)

Es el diecisiete un siglo más en el que la mayor parte de los hombres limita su vida a comer, beber, dormir, negociar en busca de bienes materiales y gozar esporádicamente de su sexo. Sin embargo en cada sitio poblado del planeta hay una minoría que se esfuerza por superar la vida ordinaria y con vehemente tesón ejecuta obras que afirmarán la calidad del hombre como criatura superior. En Europa, por ejemplo, esas minorías se cuentan por millares; en la desconocida y pequeña aldea de los Andes, los bogotanos de excepción son apenas un puñado

Diplomado de profundización cisco prueba de habilidades prácticas CCNP

La cuarta revolución industrial requiere de grandes manejos de información, las nuevas tecnologías de información cada vez aumentan la infraestructura de comunicaciones y redes de transmisión de datos, con diferentes tipologías y tipos de conexión o cableado. Es por este motivo la necesidad de profundizar mediante la plataforma Cisco, permite realizar comprensión de material teórico y práctico en la construcción, programación, conexión de redes LAN/WAN por medio de diferentes laboratorios remotos como Packet Tracer, GNS3, Smart LAB.The fourth industrial revolution requires great information management, new information technologies increasingly increase the communications infrastructure and data transmission networks, with different typologies and types of connection or wiring. It is for this reason the need to deepen through the Cisco platform, allows understanding of theoretical and practical material in the construction, programming, connection of LAN / WAN networks through different remote laboratories such as Packet Tracer, GNS3, Smart LA

Juan Rodríguez Freile (1556-1638)

Había nacido cerca de la catedral y allí corrió su infancia, pero cuando se comenzó a formar el nuevo barrio alrededor de la recién erigida iglesia de Santa Bárbara, su madre, Catalina Rodríguez, adquirió por ahí, a escasas diez cuadras de la catedral, una casita. Desde los ocho o nueve años de edad, cuando García Zorro le enseñó a leer, había mostrado desmedido interés por la lectura y por eso en la adolescencia, cuando Gonzalo García fue a buscarlo en la casita de Santa Bárbara, es posible que ya hubiese leído un centenar de libros que su padre y los paisanos españoles de su padre le habían facilitado

Efecto de la harina de achote (Bixa Orellana L.) en la pigmentación de pollos de carne COBB- 500

Efecto de la harina de achote (Bixa Orellana L.) en la pigmentación de pollos de carne COBB- 500Tesi

Unveiling the formation route of the largest galaxies in the Universe

Observational evidence indicates that the role of gas is secondary to that of gravity in the formation of the most luminous spheroids inhabiting the centres of galaxy associations, as originally conjectured in the late 80s/early 90s. However, attempts to explain the origin of the Fundamental Plane (FP) of massive early-type galaxies (ETGs) - a tilted version of the scaling relation connecting the size, velocity dispersion and mass of virialized homologous systems - based on sequences of pairwise mergers, have systematically concluded that dissipation cannot be ignored. We use controlled simulations of the pre-virialization stage of galaxy groups to show that multiple collisionless merging is capable of creating realistic first-ranked galaxies. Our mock remnants define a thin FP that perfectly fits data from all kinds of giant ETGs in the local volume, showing the existence of a unified relationship for these systems. High-ranked galaxies occupy in the FP different areas than standard objects, a segregation which is viewed essentially as zero-point offsets in the 2D correlations arising from standard projections of this plane. Our findings make a strong case for considering hierarchical dissipationless merging a viable route for the formation of the largest galaxies in the Universe

The time-scales of major mergers from simulations of isolated binary galaxy collisions

A six-dimensional parameter space based on high-resolution numerical simulations of isolated binary galaxy collisions has been constructed to investigate the dynamical friction timescales, $\tau_{\rm mer}$, for major mergers. Our experiments follow the gravitational encounters between $\sim 600$ pairs of similarly massive late- and early-type galaxies with orbital parameters compliant to the predictions of the LambdaCDM cosmology. We analyze the performance of different schemes for tracking the secular evolution of mergers, finding that the product of the intergalactic distance and velocity is best suited to identify the time of coalescence. In contrast, a widely used merger time estimator such as the exhaustion of the orbital spin is shown to systematically underpredict $\tau_ {\rm mer}$, resulting in relative errors that can reach 60% for nearly radial encounters. Regarding the internal spins of the progenitors, we find that they can lead to total variations in the merger times above 30% in highly circular encounters, whereas only that of the principal halo is capable of modulating the strength of the interaction prevailing throughout a merger. The comparison of our simulated merger times with predictions from different variants of a well-known fitting formula has revealed an only partially satisfactory agreement, which has led us to recalculate the values of the coefficients of these expressions to obtain relations that fit perfectly major mergers. The observed biases between data and predictions, that do not only apply to the present work, are inconsistent with expectations from differences in the degree of idealization of the collisions, their metric, spin-related biases, or the simulation set-up. This hints to a certain lack of accuracy of the dynamical friction modelling, arising perhaps from a still not quite complete identification of the parameters governing orbital decay.Comment: 20 pages, 11 figures, 3 tables. Accepted for publication in A&