Pulsar spin-down: the glitch-dominated rotation of PSR J0537-6910

The young, fast-spinning, X-ray pulsar J0537-6910 displays an extreme glitch activity, with large spin-ups interrupting its decelerating rotation every ~100 days. We present nearly 13 years of timing data from this pulsar, obtained with the {\it Rossi X-ray Timing Explorer}. We discovered 22 new glitches and performed a consistent analysis of all 45 glitches detected in the complete data span. Our results corroborate the previously reported strong correlation between glitch spin-up size and the time to the next glitch, a relation that has not been observed so far in any other pulsar. The spin evolution is dominated by the glitches, which occur at a rate ~3.5 per year, and the post-glitch recoveries, which prevail the entire inter-glitch intervals. This distinctive behaviour provides invaluable insights into the physics of glitches. The observations can be explained with a multi-component model which accounts for the dynamics of the neutron superfluid present in the crust and core of neutron stars. We place limits on the moment of inertia of the component responsible for the spin-up and, ignoring differential rotation, the velocity difference it can sustain with the crust. Contrary to its rapid decrease between glitches, the spin-down rate increased over the 13 years, and we find the long-term braking index $n_{\rm l}=-1.22(4)$, the only negative braking index seen in a young pulsar. We briefly discuss the plausible interpretations of this result, which is in stark contrast to the predictions of standard models of pulsar spin-down.Comment: Minor changes to match the MNRAS accepted versio

Elaboración de informes

Unidad 8 de la serie “Técnicas de comunicación” dirigida al instructor en formación que trata los temas de: Principios básicos para la elaboración de informes en lo que se refiere a la organización de su contenido, al estilo de su redacción y a su presentación.Unit 8 of the series Communication techniques directed to the instructor in training that deals with the subjects of: Basic principles for the elaboration of reports as regards the organization of its content, in the style of its writing and its presentation.Elaboración de informes: clases -- Normas para su elaboración -- Estructura -- PresentaciónnaUnidades de la serie: 1. La Comunicación; 2. La lectura; 3. Técnicas de estudio; 4. Técnicas de investigación; 5. Elaboración y presentación de trabajo; 6. Expresión oral; 7A. Expresión escrita (Definición y estructura de la oración); 7B. Expresión escrita (Oficios de las palabras en la oración articulo sustantivo, adjetivo, preposición y pronombre; 7C. Expresión escrita (Oficios de las palabras en la oración verbo, adverbio, conjunción, interjección) 7D. Expresión escrita (El párrafo, signos de puntuación y acentuación); 7E. Expresión escrita (Redacción); 8Tecnicas de comunicación (Elaboración de informes)33 página

Expresión oral

Unidad 6 de la serie “Técnicas de comunicación” en la que se describe la importancia de la expresión oral, sus objetivos, que requisitos se deben tener para que la expresión oral sea eficaz así como la importancia de la escucha en el proceso de comprensión y aprendizaje.Unit 6 of the "Communication Techniques" series, which describes the importance of oral expression, its objectives, the requirements that must be met for oral expression, the importance of listening in the process of understanding and learningExpresión oral. Importancia y objetivos -- Requisitos -- Pronunciación clara -- Entonación adecuada -- Sintaxis ágil -- Morfología segura -- Vocabulario abundante y adaptado al auditorio -- Economía verbal -- Otros requisitos -- La escucha -- Calidad -- Necesidades e intereses -- Limitación del tiempo -- Recapitulación -- Auto-evaluación final -- Bibliografíana25 página

Worldwide Workshop on Youth Involvement as a Strategy for Social, Economic and Democratic Development

Summarizes January 2000 discussions on building capacity in the field of youth service. Explores connections with social capital, economic productivity, adolescent development, marginalized youth, civic engagement, and policy. Includes country summaries

The enigmatic spin evolution of PSR J0537-6910: r-modes, gravitational waves and the case for continued timing

We discuss the unique spin evolution of the young X-ray pulsar PSR J0537-6910, a system in which the regular spin down is interrupted by glitches every few months. Drawing on the complete timing data from the Rossi X-ray Timing Explorer (RXTE, from 1999-2011), we argue that a trend in the inter-glitch behaviour points to an effective braking index close to $n=7$, much larger than expected. This value is interesting because it would accord with the neutron star spinning down due to gravitational waves from an unstable r-mode. We discuss to what extent this, admittedly speculative, scenario may be consistent and if the associated gravitational-wave signal would be within reach of ground based detectors. Our estimates suggest that one may, indeed, be able to use future observations to test the idea. Further precision timing would help enhance the achievable sensitivity and we advocate a joint observing campaign between the Neutron Star Interior Composition ExploreR (NICER) and the LIGO-Virgo network.Comment: 10 pages, 4 figures, emulate ApJ forma

Detection of magnetic moment in thin films with a home-made vibrating sample magnetometer

This paper explores the optimization of an array of pick-up coils in a home-made vibrating sample magnetometer for the detection of magnetic moment in thin films. Sensitivity function of a 4-coils Mallinson configuration was numerically studied for the determination of the physical dimensions that enhance the sensitivity of the magnetometer. By performing numerical simulations using the Biot-Savart law combined with the principle of reciprocity we were able to determine the maximum values of sensitivity and the influence of the separation of the coils on the sensitivity function. After the optimization of the pick-up coils, the vibrating sample magnetometer was able to detect the magnetic moment of a 100 nm-thickness Fe19Ni81 magnetic thin film along and perpendicular to the in-plane anisotropy easy axis. The implemented vibrating sample magnetometer is able to detect changes in the magnetic moment of ∼2 × 10-4 emu.Fil: Jordán, D.. Universidad Nacional de Ingeniería. Facultad de Ciencias; PerúFil: González Chávez, D.. Centro Brasileiro de Pesquisas Físicas; BrasilFil: Laura, D.. Universidad Nacional de Ingeniería. Facultad de Ciencias; PerúFil: Leon Hilario, Ludwin Misael. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Ingeniería. Facultad de Ciencias; PerúFil: Monteblanco, E.. Universite de Lorraine; FranciaFil: Gutarra Espinoza, Abel. Universidad Nacional de Ingeniería. Facultad de Ciencias; PerúFil: Aviles Felix, Luis Steven. Comision Nacional de Energía Atómica. Gerencia de Área Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Bariloche). División Resonancias Magnéticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin