Radio observations of Supernova Remnants and the surrounding molecular gas

Supernova Remnants (SNRs) are believed to be the main source of Galactic cosmic rays (CR). The strong SNR shocks provide ideal acceleration sites for particles of at least 10^14 eV/nucleon. Radio continuum studies of SNRs carried out with good sensitivity and high angular resolution convey information about three main aspects of the SNRs: morphology, polarization and spectrum. Based on this information it is possible to localize sites of higher compression and particle acceleration as well as the orientation and degree of order of the magnetic fields, and in some cases even its intensity. All this information, when complemented with the study of the distribution and kinematics of the surrounding interstellar gas, results in a very useful dataset to investigate the role of SNRs as cosmic ray accelerators. In this presentation, I analyze the radio observations of SNRs and surrounding molecular clouds, showing the contribution of these studies to the understanding of the role of SNRs as factories of CRs.Comment: 6 pages, 2 figures. Invited review presented at the conference on Cosmic Rays and the Interstellar Medium (CRISM-2011) held in Montpellier (France), June 26- July 1. To be published in a special issue of Memorie della Societa Astronomica Italian

The molecular clump towards the eastern border of SNR G18.8+0.3

The eastern border of the SNR G18.8+0.3, close to an HII regions complex, is a very interesting region to study the molecular gas that it is probably in contact with the SNR shock front. We observed the aforementioned region using the Atacama Submillimeter Telescope Experiment (ASTE) in the 12CO J=3-2, 13CO J=3-2, HCO+ J=4-3, and CS J=7-6 lines with an angular resolution of 22". To complement these observations, we analyzed IR, submillimeter and radio continuum archival data. In this work, we clearly show that the radio continuum "protrusion" that was early thought to belong to the SNR is an HII regions complex deeply embedded in a molecular clump. The new molecular observations reveal that this dense clump, belonging to an extended molecular cloud that surrounds the SNR southeast border, is not physically in contact with SNR G18.8+0.3, suggesting that the SNR shock front have not yet reached it or maybe they are located at different distances. We found some young stellar objects embedded in the molecular clump, suggesting that their formation should be approximately coeval with the SN explosion.Comment: Accepted for publication in A&A (Sept. 7, 2012

A Multi-Wavelength Study of the Western Lobe of W50 Powered by the Galactic Microquasar SS 433

W50 remains the only supernova remnant (SNR) confirmed to harbor a microquasar: the powerful enigmatic source SS 433. Our past study of this fascinating SNR revealed two X-ray lobes distorting the radio shell as well as non-thermal X-rays at the site of interaction between the SS 433 eastern jet and the eastern lobe of W50. In this paper we present the results of a 75 ksec CHANDRA ACIS-I observation of the peak of W50-west targeted to 1) determine the nature of the X-ray emission and 2) correlate the X-ray emission with that in the radio and infrared domains. We have confirmed that at the site of interaction between the western jet of SS 433 and dense interstellar gas the X-ray emission is non-thermal in nature. The helical pattern observed in radio is also seen with CHANDRA. No correlation was found between the infrared and X-ray emission.Comment: A refereed publication, submitted Sept. 30, 2004, accepted Jan. 12, 2005, to appear in Advances in Space Research. 7 pages, including 4 figures (3 color) & 1 table (the resolution of most figures has been reduced for astro-ph submission only). A gzipped postscript or pdf version of the paper with high-resolution images can be downloaded from: http://aurora.physics.umanitoba.ca/~moldowan/Astro-Ph

Willpower and ego depletion: Useful constructs?

It is widely recognized that the ability to exert will and defy the temptation of short-term rewards in favor of long term goals has many significant implications and is predictive of increased well-being across many domains. The American Psychological Association characterizes willpower as “the psychological science of self-control”, and their recent survey regarding Americans’ perception of their own self-control, cited the lack of will-power as the primary reason they fail to follow through with making healthy life-style changes. The “strength” model of self-control conceptualizes willpower as a limited resource which cannot be sustained indefinitely. According to the model, expending effort to exert self-control results in a reduced ability for individuals to exert self-control in a subsequent task—a psychological state known as ego depletion. Numerous investigations have replicated this effect across multiple domains and have also examined the influence of variables that moderate ego depletion. However, recent regression analyses have strongly suggested that the effect size for ego depletion is substantially smaller than was originally computed. In addition, despite widespread acceptance in both the popular press and the scientific study of psychology, the strength model has come under criticism that it has evolved into an over-reaching and unfalsifiable theory that should be subsumed under a more comprehensive theory of self-control that integrates traditional influences on self-control, including motivation, learning, and self- efficacy

The psychology and science of happiness: What does the research say?

This paper surveys the scientific evidence regarding the nature of human happiness by drawing upon numerous studies in social science domains: namely psychology, but also related fields of business leadership and consulting, economics, and behavioral economics. Beginning with a definition and narrowing of the terminology, the review moves toward a brief sketch of measurement methods in the topic. Subjective well-being and happiness are then explored within the framework of psychological theories of happiness, including tension-reduction and goal attainment theories, activity and process theories, and genetic and biologic dispositional theory. Evolving views regarding hedonic adaptation as a key process underlying happiness is examined, as well as Lyubomirsky and Layous’ (2013) comprehensive model of happiness as a framework that encompasses the entire scope of psychological theories regarding happiness. Finally, the correlational evidence related to the various components of happiness is reviewed, concluding with the observation that although strong correlational evidence is linked to well-being, happiness is a concept that defies unequivocal causal attributions because it contains a complex amalgam of interrelated and bi-reciprocal variables

Supernova Remnants seen through the spectrum

Las Supernovas (SN) son uno de los eventos más espectaculares y energéticos del Universo. Los Remanentes de Supernova (RSN) son las estructuras que resultan de dichas explosiones estelares. Su evolución modifica en forma irreversible las propiedades físicas y químicas de su entorno, convirtiéndose así en un laboratorio único para investigar condiciones extremas, imposibles de alcanzar en laboratorios terrestres. Pueden radiar por miles de años y a través de todo el espectro electromagnético, pero las características de dicha radiación varían de una banda espectral a otra. Este trabajo presenta una breve síntesis de la información que aportan los telescopios operando en diferentes rangos espectrales, desde ondas de radio hasta los rayos gamma de muy alta energía.Supernovae (SN) are one of the most spectacular and energetic events in the Universe. Supernova Remnants (SNR) are the structures created after such stellar explosions. Their evolution irreversibly modifies the physical and chemical properties of the surroundings, thus becoming a laboratory unique to investigate extreme conditions, impossible to be attained in terrestrial laboratories. The SNRs can radiate during thousands of years and throughout the whole electromagnetic spectrum, but the characteristics of the radiation vary from one spectral band to the other. This article presents a brief synthesis of the information provided by telescopes operating in different spectral ranges, from radio waves to the very energetic gamma rays.Fil: 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; Argentin

The neutral gas in the environs of the Geminga gamma-ray pulsar

We present a high-resolution (24 arcsec) study of the HI interstellar gas distribution around the radio-quiet neutron star Geminga. Based on Very Large Array (VLA) and MPIfR Effelsberg telescope data, we analyzed a 40' x 40' field around Geminga. These observations have revealed the presence of a neutral gas shell, 0.4 pc in radius, with an associated HI mass of 0.8 Msun, which surrounds Geminga at a radial velocity compatible with the kinematical distance of the neutron star. In addition, morphological agreement is observed between the internal face of the HI shell and the brightest structure of Geminga's tail observed in X-rays.We explore the possibility that this morphological agreement is the result of a physical association.Comment: One tarfile including a Latex file (7 pages) and two figures. Paper accepted for publication in Advances in Space Research; typos corrected; changes in section Results and Discussion after referee's suggestions. S. Johnston's affilation correcte