The Microlensing Properties of a Sample of 87 Lensed Quasars

Gravitational microlensing is a powerful tool for probing the physical properties of quasar accretion disks and properties of the lens galaxy such as its dark matter fraction and mean stellar mass. Unfortunately the number of lensed quasars ($\sim 90$) exceeds our monitoring capabilities. Thus, estimating their microlensing properties is important for identifying good microlensing candidates as well as for the expectations of future surveys. In this work we estimate the microlensing properties of a sample of 87 lensed quasars. While the median Einstein radius crossing time scale is 20.6 years, the median source crossing time scale is 7.3 months. Broadly speaking, this means that on $\sim 10$ year timescales roughly half the lenses will be quiescent, with the source in a broad demagnified valley, and roughly half will be active with the source lying in the caustic ridges. We also found that the location of the lens system relative to the CMB dipole has a modest effect on microlensing timescales, and in theory microlensing could be used to confirm the kinematic origin of the dipole. As a corollary of our study we analyzed the accretion rate parameters in a sub-sample of 32 lensed quasars. At fixed black hole mass, it is possible to sample a broad range of luminosities (i.e., Eddington factors) if it becomes feasible to monitor fainter lenses.Comment: 31 pages, 7 figures, 2 tables, corrected typos in Table 2, revised version accepted for publication in Ap

El “otro” como definidor del “yo” en el Siglo de Oro: la estrategia imagológica

Numerosos críticos han analizado obras literarias en general, y textos del Siglo de Oro en particular, detectando los prejuicios que utilizan los escritores para describir lo ajeno, la otredad. Este trabajo se fija en el caso concreto de Francisco de Quevedo para precisar que, aunque el retrato del otro puede servir para identificar características del autor, también está fuertemente determinado por las circunstancias concretas (históricas y, sobre todo, genéricas) del texto. Many critics have analyzed literary works in general, and Golden Age texts in particular, to detect in them the prejudices that writers employ to describe that which is foreign, otherness. This paper focuses on the specific case of Francisco de Quevedo in order to highlight that, while the portrait of the Other may serve to identify information relevant to the author, it is also fundamentally determined by the concrete historical, and above all generic, circumstances of the text

Los textos de la "Segunda parte" de Calderón

El artículo se ocupa de discutir la validez de los textos que componen la “Segunda parte” de comedias de Pedro Calderón de la Barca, a partir de trabajos previos sobre cada texto en específico llevados a cabo por el Grupo Calderón de la Universidad de Santiago de Compostela (GIC). El análisis detenido de textos como “El mayor encanto, amor”, “El médico de su honra” o “El mayor monstruo” lleva a afirmar que, en general, los textos de la “Segunda parte” deben ser manejados como base para la edición de comedias calderonianas, si bien existe desequilibrio entre la cantidad de errores presentes en el texto de unas comedias frente a otras

El motivo de la tormenta: la transformación de la épica

Este trabajo pretende explicar la técnica mediante la cual Quevedo resemantiza un motivo ya muy desgastado a la altura del siglo XVII. Como en otros aspectos estilísticos de su literatura, el escritor acudirá al uso catacrético de los tropos y se dirigirá, en lo ideológico, hacia un significado más alegórico que descriptivo y épico del tópico. This essay will attempt to explain the technique by which Quevedo revitalized a motif which was overused in the Sixteenth Century. As in othe stylistic aspects of his work, the writer calls on the catachretical use of tropes and looks, ideologically speaking, towards a more allegorical, descriptive and epic meaning of the cliché

Revealing the Structure of an Accretion Disk Through Energy Dependent X-ray Microlensing

We present results from monitoring observations of the gravitationally lensed quasar RX J1131-1231 performed with the Chandra X-ray Observatory. The X-ray observations were planned with relatively long exposures that allowed a search for energy-dependent microlensing in the soft (0.2-2 keV) and hard (2-10 keV) light curves of the images of RX J1131-1231. We detect significant microlensing in the X-ray light-curves of images A and D, and energy-dependent microlensing of image D. The magnification of the soft band appears to be larger than that in the hard band by a factor of ~ 1.3 when image D becomes more magnified. This can be explained by the difference between a compact, softer-spectrum corona that is producing a more extended, harder spectrum reflection component off the disk. This is supported by the evolution of the fluorescent iron line in image D over three consecutive time-averaged phases of the light curve. In the first period, a Fe line at E = 6.36(-0.16,+0.13) keV is detected (at > 99% confidence). In the second period, two Fe lines are detected, one at E = 5.47(-0.08,+0.06) keV (detected at > 99% confidence) and another at E = 6.02(-0.07,+0.09) keV (marginally detected at > 90% confidence), and in the third period, a broadened Fe line at 6.42(-0.15,+0.19) keV is detected (at > 99% confidence). This evolution of the Fe line profile during the microlensing event is consistent with the line distortion expected when a caustic passes over the inner disk where the shape of the fluorescent Fe line is distorted by General Relativistic and Doppler effects.Comment: 20 pages, includes 10 figures, submitted to Ap

A Robust Determination of the size of quasar accretion disks using gravitational microlensing

Using microlensing measurements from a sample of 27 image-pairs of 19 lensed quasars we determine a maximum likelihood estimate for the accretion disk size of an {{\em}average} quasar of $r_s=4.0^{+2.4}_{-3.1}$ light days at rest frame $=1736$\AA\ for microlenses with a mean mass of $=0.3M_\odot$. This value, in good agreement with previous results from smaller samples, is roughly a factor of 5 greater than the predictions of the standard thin disk model. The individual size estimates for the 19 quasars in our sample are also in excellent agreement with the results of the joint maximum likelihood analysis.Comment: 6 pages, 3 figures, submitted to Ap

Hubble Diagram of Gamma-Rays Bursts calibrated with Gurzadyan-Xue Cosmology

Gamma-ray bursts (GRBs) being the most luminous among known cosmic objects carry an essential potential for cosmological studies if properly used as standard candles. In this paper we test with GRBs the cosmological predictions of the Gurzadyan-Xue (GX) model of dark energy, a novel theory that predicts, without any free parameters, the current vacuum fluctuation energy density close to the value inferred from the SNIa observations. We also compare the GX results with those predicted by the concordance scenario $\Lambda$-CDM. According to the statistical approach by Schaefer (2007), the use of several empirical relations obtained from GRBs observables, after a consistent calibration for a specific model, enables one to probe current cosmological models. Based on this recently introduced method, we use the 69 GRBs sample collected by Schaefer (2007); and the most recently released SWIFT satellite data (Sakamoto et al. 2007) together with the 41 GRBs sample collected by Rizzuto et al. (2007), which has the more firmly determined redshifts. Both data samples span a distance scale up to redshift about 7. We show that the GX models are compatible with the Hubble diagram of the Schaefer (2007) 69 GRBs sample. Such adjustment is almost identical to the one for the concordance $\Lambda$-CDM.Comment: 9 pages, 17 figures, 11 tables; Astr. & Astrophys. (in press

Imagino, construyo y vivo mi mundo, a trav?s de la fantas?a de las artes y de la literatura

74 P?ginasRecurso Electr?nicoEl Proyecto trata sobre la importancia de las artes y la literatura como herramientas para fortalecer el aprendizaje significativo y la comunicaci?n, se aplic? en el Centro Educativo El Vergel ubicado en el corregimiento de San Antonio de Prado de la Ciudad de Medell?n. La propuesta surgi? ante la observaci?n de los comportamientos de los ni?os y el inter?s por las artes y la literatura como fortalecimiento de los procesos de ense?anza aprendizaje de lectura, el ejercicio escritural llam? la atenci?n de los docentes, iniciando as? la b?squeda de estrategias y t?cnicas para comenzar a interactuar con los ni?os/as a trav?s de actividades y herramientas sobre temas relacionados con educaci?n desde la primera infancia (educaci?n inicial) con el prop?sito de desarrollar habilidades, destrezas y generar nuevos espacios para profundizar las artes y la literatura. Se realizaron actividades frente al tema y surgi? gran impacto en los ni?os y padres de familias mediante la elaboraci?n de un cronograma de actividades, gu?as de trabajo las cuales se llevaron a cabo de manera eficaz en el grupo de estudio seleccionado. En diferentes dimensiones y en las fechas estipuladas se desarrollaron las actividades con los ni?os/as del centro educativo aplicando la encuesta (padres de familia y profesores), actividades sobre artes y literatura, lo cual despert? de forma positiva la utilidad de las herramientas para imaginar, crear cosas nuevas. Se tomaron elementos de los pedagogos Jean Piaget, Ausubel y Vigotsky.ABSTRACT. The research project is about the importance of arts and literature as tools to strengthen meaningful learning and communication , applied in the Education Center El Vergel located in the village of San Antonio de Prado of the City of Medellin. The proposal arose from the observation of the behaviors of children and interest in the arts and literature as strengthening the teaching and learning of reading the scriptural exercise , this factor attracted the attention of teachers , initiating search strategies and techniques to start interacting with children through activities and tools on topics related to education from early childhood care ( early childhood education ) in order to develop skills and generate new opportunities for deepening arts and literature. Activities were conducted on the issue and came up big impact on children and parents by developing a schedule of activities and working guidelines, which were carried out effectively in the selected study group. From the different dimensions and the dates, stipulated activities were developed with children of the school using a survey (parents and teachers), activities on the arts and literature, which woke positively the usefulness of tools to imagine and create new things. Elements pedagogues Jean Piaget, Ausubel and Vygotsky, stadiums, and meaningful sociocultural learning theories were taken.INTRODUCCI?N 17 1. PROBLEMA DE INVESTIGACI?N 18 1.1 ANTECEDENTES 18 1.2 PLANTEAMIENTO DEL PROBLEMA 18 1.3 PREGUNTA PROBLEMATIZADORA 19 2. JUSTIFICACI?N 20 3. OBJETIVOS 22 3.1 OBJETIVO GENERAL 22 3. 2 OBJETIVOS ESPEC?FICOS 22 4. MARCO TE?RICO 23 4.1 APRENDIZAJE SIGNIFICATIVO 25 4.2 APRENDIZAJE SIGNIFICATIVO Y APRENDIZAJE MEC?NICO 25 4.3 APRENDIZAJE POR DESCUBRIMIENTO Y APRENDIZAJE POR RECEPCI? 26 4.4 EL APRENDIZAJE POR DESCUBRIMIENTO 27 4.5 REQUISITOS PARA EL APRENDIZAJE SIGNIFICATIVO 27 4.6 PLANTEAMIENTO TE?RICO DE PIAGET 29 5. MARCO LEGAL 31 5.1 GENERALIDADES DE LOS LINEAMIENTOS EDUCATIVOS 32 5.2 COMPONENTES DE LOS LINEAMIENTOS EDUCATIVOS 32 Constituci?n Pol?tica de Colombia: 33 6. DISE?O METODOLOGICO 35 6.1 ?QU? ES INVESTIGACI?N CUALITATIVA? 36 6.2 TIPO DE INVESTIGACI?N 36 6.3 T?CNICAS DE INVESTIGACI?N 36 6.4 POBLACI?N 37 6.5 MUESTRA 37 6.6 INSTRUMENTOS DE RECOLECCI?N DE LA INFORMACI?N 38 7. AN?LISIS DE LA INFORMACI?N 40 7.1. ACTIVIDADES POR DESARROLLAR 41 8. CRONOGRAMA DE ACTIVIDADES 41 9. PRESUPUESTO 42 10. RECURSOS 44 11. CONCLUSIONES 45 RECOMENDACIONES 46 REFERENCIAS 47 ANEXOS 5