Radio Observations of SNR Environments

Most supernova remnants (SNRs) in our Galaxy are expected to be close to their parent molecular clouds. The interaction between SNRs and interstellar clouds not only alter the morphology and evolution of a SNR but also heat, compress, disrupt or modify the chemistry of the cloud. The turbulence generated in molecular clouds can trigger star formation. Radio emission from atomic and molecular lines toward SNRs provide unvaluable information to describe the ambient in which a SNR is evolving and determine possible sites of SNR-interstellar cloud interaction. The detection of OH masers in the satellite line at 1720 MHz can set strong constraints in the characteristics of the shocked ambient medium as well as on the dynamics of the SNR shock front. In this article I review some relevant results derived from radio observations in different spectral lines and under a variety of conditions towards SNRs and their environments.Se calcula que la mayoría de los remanentes de supernovas (RSNs) en nuestra galaxia se encuentran muy cerca o dentro de las nubes moleculares en las que nacieron sus estrellas progenitoras. Cuando un RSN interactua con nubes interestelares, no solo se altera la morfología y la evolución del RSN sino que también las nubes se calientan, se comprimen, se disocian, o sufren modificaciones en su química. La turbulencia que se genera en las nubes moleculares puede desencadenar formación estelar. El estudio de la emisión en radio en lıneas atomicas y moleculares proveniente de RSNs aporta información fundamental para describir el ambiente en el cual evoluciona un RSN y determinar posibles sitios de interacción RSN-nube interestelar. La detección de masers de OH en la linea satélite de 1720 MHz permite acotar tanto las características del medio ambiente chocado como de la dinámica del frente de choque del RSN. En este artículo presento una recopilación de distintos resultados obtenidos a partir de observaciones en radio en diferentes líneas espectrales y bajo distintas condiciones en dirección a algunos RSNs y sus entornos.Fil: Reynoso, Estela Marta. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin

Muere una estrella

Qué observó en el cielo nocturno un rosarino aficionado a la astronomía y por qué su observación causó gran revuelo, recogido por los medios, entre los astrónomos profesionales. (Artículo de divulgación)Fil: Reynoso, Estela Marta. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin

Highlights on the interaction between SNRs and the surrounding medium

When a star explodes as a supernova (SN), about 1051 ergs of energy are released in the interstellar medium (ISM). Most SN outbursts occur near or inside the molecular clouds were their pogenitor stars were born. An increasing number of SN remnants (SNRs) show signatures of being inter- acting with neighbouring clouds. Understanding such interactions is cru- cial both to determine the physical and dynamical conditions and structure of the ISM and to learn about the physical processes that take place in an SNR shock front. Even if molecular clouds are absent, pre-existing mag- netic fields can play a key role on the morphology of an SNR. In this paper I review some recent results on the interplay between Galactic SNRs and their surroundings.Cuando una estrella explota como supernova (SN), se liberan unos 1051 ergios de energía en el medio interestelar (MIE). La mayoría de las explosiones ocurren cerca o dentro de la nube molecular donde nacieron las estrellas progenitoras. Cada vez más remanentes de supernovas (RSNs) muestran evidencia de interacción con nubes vecinas. Comprender tales interacciones es crucial tanto para determinar las condiciones físicas y dinámicas y la estructura del MIE como para conocer los procesos físicos que se dan en el frente de choque de un RSN. Aún en ausencia de nubes moleculares, los campos magnéticos pre-existentes pueden ser determinantes en la morfología de un RSN. Este artículo presenta una recopilación de los resultados más recientes sobre la influencia mutua entre RSNs galácticos y sus entornos.Fil: Reynoso, Estela Marta. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin

New perspectives on the supernova remnant Puppis A based on a radio polarization study

We present a polarization study towards the supernova remnant (SNR) Puppis A based on original observations performed with the Australia Telescope Compact Array. Based on the analysis of a feature detected outside the SNR shell (called 'the tail' throughout the paper), it was possible to disentangle the emission with origin in Puppis A itself from that coming from the foreground Vela SNR. We found a very low polarization fraction, of about 3 per cent on average. The upper limit of the magnetic field component parallel to the line of sight is estimated to be B ~ 20 μG. The statistical behaviour of the magnetic vectors shows two preferential directions, almost perpendicular to each other, which are approximately aligned with the flat edges of Puppis A. A third, narrow peak oriented perpendicular to the Galactic plane suggests the existence of an interstellar magnetic field locally aligned in this direction. There is evidence that the magnetic vectors along the shell are aligned with the shock front direction. The low polarization fraction and the statistical behaviour of the magnetic vectors are compatible with a scenario where the SNR evolves inside a stellar wind bubble with a box-like morphology, produced by the interaction of the different stellar winds, one of them magnetized, launched by the SN progenitor. This scenario can furthermore explain the morphology of Puppis A, rendering little support to the previously accepted picture which involved strong density gradients to explain the flat, eastern edge of the shell.Fil: Reynoso, Estela Marta. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Velázquez, P. F.. Universidad Nacional Autónoma de México. Instituto de Ciencias Nucleares; MéxicoFil: Cichowolski, Silvina. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin

On the Radio Polarization Signature of Efficient and Inefficient Particle Acceleration in Supernova Remnant SN 1006

We present a radio polarization study of SN 1006, based on combined VLA and ATCA observations at 20 cm that resulted in sensitive images with an angular resolution of 10 arcsec. The fractional polarization in the two bright radio and X-ray lobes of the SNR is measured to be 0.17, while in the southeastern sector, where the radio and non-thermal X-ray emission are much weaker, the polarization fraction reaches a value of 0.6 +- 0.2, close to the theoretical limit of 0.7. We interpret this result as evidence of a disordered, turbulent magnetic field in the lobes, where particle acceleration is believed to be efficient, and a highly ordered field in the southeast, where the acceleration efficiency has been shown to be very low. Utilizing the frequency coverage of our observations, an average rotation measure of ~12 rad/m2 is determined from the combined data set, which is then used to obtain the intrinsic direction of the magnetic field vectors. While the orientation of magnetic field vectors across the SNR shell appear radial, a large fraction of the magnetic vectors lie parallel to the Galactic Plane. Along the highly polarized southeastern rim, the field is aligned tangent to the shock, and therefore also nearly parallel to the Galactic Plane. These results strongly suggest that the ambient field surrounding SN 1006 is aligned with this direction (i.e., from northeast to southwest) and that the bright lobes are due to a polar cap geometry. Our study establishes that the most efficient particle acceleration and generation of magnetic turbulence in SN 1006 is attained for shocks in which the magnetic field direction and shock normal are quasi-parallel, while inefficient acceleration and little to no generation of magnetic turbulence obtains for the quasi-perpendicular case.Comment: Accepted for publication in Astronomical Journa

Redesigning a Bachelor Degree in Mexico for Accreditation

Accreditation is a major issue for Mexican universities. As of February 2009 there were 48 technology-related programs at 31 universities accredited in Mexico, 14 of them in Information Systems (IS). This paper describes some experiences in redesigning an IS program for accreditation purposes that can be helpful to other programs that are thinking about starting an accreditation initiative. This paper describes the four profiles defined by accreditation bodies and compares them to what programs in institutions around the world are teaching

Enhanced Learning Using Mutimedia-Interactive Systems: An Experimental Study

The education field is in a process of change driven by new developments in multimedia technology, which is being used as a complementary alternative for teaching purposes. This paper describes a thesis project developed through an exploratory study comparing the effects of using three different teaching approaches: traditional teacher-led instruction, web page instruction and a multimedia-interactive system. The principal objective is to find out whether the use of a prototype multimedia-interactive delivers better outcomes in teaching complex subjects such as data structures, than web page and traditional teacher-led instruction approaches. Information Systems Design Theory was used to develop a multimediainteractive tool. Students were taught to use binary trees to compare the three teaching methods. Pilot test results show that there are significant differences in performance of students who used the multimedia-interactive tool. It is concluded that the multimedia-interactive system prototype can effectively be used to help students learn binary trees

The Public Institutiones Of Higher Education: Analysis Of The Factors That Affects The Educational System

En la presente investigación se retoma la teoría de la motivación humana que propone jerarquías de las necesidades, puesto que los seres humanos son motivados por necesidades múltiples y que solo existen en un orden jerárquico. Sin embargo, en las instituciones Públicas de Educación Superior en México, no hay resultados contundentes de la aplicación de esta teoría, ya que las áreas de oportunidad en el factor de motivación refleja que el personal que labora en estas instituciones no es se siente motivado por el trabajo que desempeña. Se analizaron siete instituciones de educación superior donde se encuestaron 224 sujetos divididos en directivo, mandos medios y personal operativo, en los subsistemas de educación Tecnológicas, Autónomas, Politécnicas, Tecnológicos de Estudios Superiores e Institutos Tecnológicos Superiores, en los estados de México, Puebla e Hidalgo. Considerando los factores de comunicación, motivación, satisfacción laboral, identidad, trabajo en equipo y liderazgo. Se logró comprobar la hipótesis estadística planteada, para lo cual se analizaron los factores de comunicación, motivación, satisfacción laboral, identidad, trabajo en equipo y liderazgo en los directivos, mandos medios y personal operativo. A partir de lo anterior, se acepta la hipótesis alternativa, es decir, que existe correlación significativa entre todas las variables estudiadas y se puede afirmar que son generalizables para toda la población.The purpose of the present research is to study the effects of statistical data on the behavior of Higher Education Faculties (IPES) in some states of the Mexican Republic. According to the ANUIES (2012) data base, in Hidalgo State 17% of students concluded their career, while 10.7% is graduated, this is associated that some students delay the academic process. In Mexico State 14.4% students complete the higher studies, but only 74.25% obtain their professional grade. Puebla indicates that 18% finished their studies and only 76% are graduated. Therefore, the most outstanding problems in higher education are the following situations: • Inequity in access to the detriment of young people from low economic status. • Limited relations with industrial-productive areas. • Discrepancy with other educational levels. • Insufficient economical support for research in public Universities and restricted relationship with the science and technology system. • Weak relevance and quality. • Growth of student population in higher institutions. Finally, the problematic considers that IPES has influences in the commitment of human resource to improve the results of the academic institutions, since in the higher education is one of the main factors in the educational process. Within the functional areas of the IPES, the main component to be studied is the academic employees, who provide the institution with knowledge, skills, abilities and capacities, which become human resource advantages; In return for this, the employees obtain benefits of salary, rewards, gratuities and promotions, therefore the degree of satisfaction increases its disposition when maintaining lines of activity with the educational organization. In this relationship of economic-social interchange the norm of reciprocity and variables such as communication, motivation, job satisfaction, identity, teamwork and leadership, so the degree of employee satisfaction generates a sense of belonging that favors the achievement of organizational objectives

SNR Puppis A: molecular gas possibly associated with the brightest X-ray feature

We analize the 12CO emission towards the brightest X-ray knot in the supernova remnant (SNR) Puppis A. The observations were performed with the SEST telescope in the 12CO J=1--0 and 2--1 lines (beams of 45" and 23" respectively). We discovered a compact molecular clump near the radio and X-ray maxima and calculated its physical parameters. From the comparison with Chandra X-ray data we conclude that this molecular clump lies in front of Puppis A along the line of sight. The possibilities of a recent interaction between the SNR and the molecular gas are analyzed.Se analiza la emisión del 12CO en la región más brillante de emisión de rayos X del remanente de supernova (RSN) Puppis A. Las observaciones fueron realizadas en las transiciones J=1–0 y 2–1 con el telescopio sueco SEST con resoluciones angulares de 45′′ y 23′′ respectivamente para ambas líneas. Se descubrio la presencia de un grumo molecular compacto cerca del máximo en radio y en rayos X. Se calculan los parámetros físicos de dicha componente molecular. De la comparación con datos en rayos X del satélite Chandra se concluye que dicho grumo molecular se encuentra por delante del RSN Puppis A a lo largo de la visual. Se analiza la posibilidad de una reciente interacción entre el frente de choque del RSN y el gas molecular.Fil: Paron, Sergio Ariel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Dubner, Gloria Mabel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Reynoso, Estela Marta. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin