"Distance mapping" and the 3-D structure of BB +30 3639

BD +30 3639 is a member of a group of uncommon planetary nebula with Wolf-Rayet central star and higher expansion velocities in [O III] than in [N II] lines. Images and high-resolution spectra from the literature are used in order to construct a 3-D model of the nebula using the morpho-kinematic code SHAPE. We find that two homologous expansion laws are needed for the [N II] and [O III] shell. We conclude that the internal velocity field of BD +30 3639 decreases with the distance from the central star at least between the [O III] and [N II] shells. A cylindrical velocity component is used to replicate the high-speed bipolar collimated outflows. We also present a new kinematic analysis technique called "distance mapping". It uses the observed proper motion vectors and the 3-D velocity field to generate maps that can be used as a constraint to the morpho-kinematic modeling with SHAPE as well as improve the accuracy for distance determination. It is applied to BD+30 3639 using 178 internal proper motion vectors from Li et al. (2002) and our 3-D velocity field to determine a distance of 1.52 \pm 0.21 kpc. Finally, we find evidence for an interaction between the eastern part of nebula and the ambient H2 molecular gas.Comment: 11 pages, 12 figures, 1 table, Accepted to MNRA

Representaciones del poder y laconismo en el siglo diecisiete español

El vínculo entre el estilo y el ser elaborado por Séneca ocupa un lugar importante en la literatura política del siglo XVII español. Considerando el modo en que este corpus retoma la articulación senequista de la expresión verbal, el gesto corporal y el mérito social, el presente análisis aborda el culto a la brevedad como modo de comunicación a la vez que de exhibición física. Los escritos de dos de sus teóricos más destacados, Gracián y Quevedo, servirán para ejemplificar la concepción del laconismo como forma de esgrimir eficacia política y gravedad masculina. Lejos de conformarse a un molde de conducta homogenizador, las formulaciones lingüísticas y fisonómicas del poder varonil varían significativamente y apuntan a proyectos sociales antitéticos. Mientras que la concisión graciana se identifica con la contención corporal y verbal propia del proceso civilizador, la brevedad quevediana apela a una violencia fundacional transgresora.Centro de Estudios de Teoría y Crítica Literari

"La caída para levantarse": san Pablo, espejo de Quevedo

This study reflects upon La caída para levantarse, focusing in particular on its representation of Saint Paul as a transhistorical model of eloquence. Fusing his authorial project with the apostle’s auratic word, Quevedo endows his own writing with a providential stature. While thus engaging in a deliberate anachronism that obviates the differences between their respective historical horizons, he concomitantly foregrounds the relevance of Pauline language to the conflicted cultural context of the Counter Reformation. Addressed here are both the way in which Quevedo exploits the argumentative versatility already present in the rhetoric of his precursor, and the audacious manipulation entailed in his adaptation of the apostle’s millenarian discourse to the requirements of baroque ingenuity.Este estudio reflexiona sobre la obra titulada La caída para levantarse, centrando su atención en la representación de san Pablo como un personaje transhistórico modelo de elocuencia. Uniendo su proyecto autorial a la palabra del apóstol de las gentes, Quevedo dota su propia escritura de una talla providencial. Utilizando un anacronismo deliberado que obvia las diferencias entre los respectivos horizontes históricos, don Francisco aplica la relevancia del lenguaje paulino al conflictivo contexto cultural de la Contrarreforma. Aquí se analiza la versatilidad argumentativa presente en la retórica de su predecesor junto con la audaz manipulación implicada en su adaptación del discurso milenario del Apóstol a las necesidades de la ingenuidad barroca

Borges criollista y clásico: cambio y continuidad en su lectura de Quevedo

Este artículo estudia los retratos de Quevedo que surgen en determinados momentos de la obra de Borges y relaciona sus diversas representaciones a poéticas bien diferenciadas. Se consideran sobre todo dos apropiaciones del autor español: una que privilegia las dimensiones retóricas y sensoriales de su escritura, destacando su repercusión pública y política, y otra que enfatiza su condición de hombre letras, de relevancia puramente estilística. La primera caracterización corresponde a un joven Borges criollista, dedicado a la definición de una metafísica local, y la segunda a un Borges más maduro que, distanciándose del nacionalismo, ensancha la tradición argentina a la cultura universal. Estas concepciones de la literatura, así como las visiones de Quevedo en las que se reflejan, no están exentas de convergencias. En este sentido, se concluye el análisis atendiendo a una síntesis de carácter hermenéutico que emerge en la poesía tardía de Borges, en la que coexisten el Quevedo épico y el letrado.This article studies the portrayals of Quevedo that emerge at given moments of Borges’ career, relating these different representations to distinctive authorial agendas. Particular attention is directed at two appropriations of the Spanish author: one which privileges the rhetorical and sensorial dimensions of his writing, emphasizing its public and political repercussions, and another which stresses his condition as a man of letters, of relevance purely because of his efficacious syntax. The first characterization mirrors the ideals of a young criollista Borges, occupied with the conception of a local metaphysics, and the second is to be identified with a more mature Borges who distances himself from his earlier nationalist interests and renders Argentinean tradition universal. These poetics, like the visions of Quevedo in which they are reflected, do, albeit, present certain convergences. In this sense, the analysis concludes with a discussion of the hermeneutical synthesis that emerges in Borges’ late poetry, where the epic and the literary Quevedo coexist

Laser-Guided Magic Bullets - a Non-Antibiotic Answer to O'Neill.

In the United Kingdom, the recently-published O’Neill Report [1] provides recommendations for the continuance of the battle between mankind’s antibiotics and our microbial foes. While there is also the mention of alternative – i.e., non-antibiotic – approaches to infection control, it appears that other biologicals such as bacteriophages and vaccines are those envisaged, rather than other chemical approaches

Migrants: Signs of a New Era. Interview with Father Solalinde.

Translation into English of the interview to Father Solalinde

The post-AGB evolution of AGB mass loss variations

We present new numerical hydrodynamical modelling of the evolution of Asymptotic Giant Branch (AGB) mass loss fluctuations during the post-AGB/Planetary Nebula phase. These models show that after ionization, the observable effects of the mass loss fluctuations disappear in a few thousand years, consistent with the fact that only few PNe have been found to be surrounded by `rings'. We derive the observational characteristics of these rings, and compare them to reported observations of the rings around NGC 6543, finding a good match of emission properties and line shapes. We predict small variations in the observable electron temperatures.Comment: 12 pages, 13 figures, accepted by A&

Young Planetary Nebulae: Hubble Space Telescope Imaging and a New Morphological Classification System

Using Hubble Space Telescope images of 119 young planetary nebulae, most of which have not previously been published, we have devised a comprehensive morphological classification system for these objects. This system generalizes a recently devised system for pre-planetary nebulae, which are the immediate progenitors of planetary nebulae (PNs). Unlike previous classification studies, we have focussed primarily on young PNs rather than all PNs, because the former best show the influences or symmetries imposed on them by the dominant physical processes operating at the first and primary stage of the shaping process. Older PNs develop instabilities, interact with the ambient interstellar medium, and are subject to the passage of photoionization fronts, all of which obscure the underlying symmetries and geometries imposed early on. Our classification system is designed to suffer minimal prejudice regarding the underlying physical causes of the different shapes and structures seen in our PN sample, however, in many cases, physical causes are readily suggested by the geometry, along with the kinematics that have been measured in some systems. Secondary characteristics in our system such as ansae indicate the impact of a jet upon a slower-moving, prior wind; a waist is the signature of a strong equatorial concentration of matter, whether it be outflowing or in a bound Keplerian disk, and point symmetry indicates a secular trend, presumably precession, in the orientation of the central driver of a rapid, collimated outflow.Comment: (to appear in The Astronomical Journal, March 2011.) The quality of the figures as it appears in the arXiv pdf output is not up-to-par; the full ms with high-quality figures is available by anonymous FTP at ftp://ftp.astro.ucla.edu/pub/morris/sahai_AJ_360163.pd

The triple-shell structure and collimated outflows of the planetary nebula NGC 6891

Narrow-band H$\alpha$ and [N {\sc ii}] images and high-dispersion spatially-resolved echelle spectroscopy of the planetary nebula NGC 6891 are presented. These observations show a great wealth of structures. The bright central nebula is surrounded by an attached shell and a detached outer halo. Both the inner and intermediate shells can be described as ellipsoids with similar major to minor axial ratios, but different spatial orientations. The kinematical ages of the intermediate shell and halo are 4,800 and 28,000 years, respectively. The inter-shell time lapse is in good agreement with the evolutionary inter-pulse time lapse. A highly collimated outflow is observed to protrude from the tips of the major axis of the inner nebula and impact on the outer edge of the intermediate shell. Kinematics and excitation of this outflow provide conclusive evidence that it is deflected during the interaction with the outer edge of the intermediate shell. At the same time, both the kinematics and the morphology of the intermediate shell appear to be affected by this interaction.Comment: To be published in MNRAS, 9 pages, 5 figure

Abell 41: shaping of a planetary nebula by a binary central star?

We present the first detailed spatio-kinematical analysis and modelling of the planetary nebula Abell 41, which is known to contain the well-studied close-binary system MT Ser. This object represents an important test case in the study of the evolution of planetary nebulae with binary central stars as current evolutionary theories predict that the binary plane should be aligned perpendicular to the symmetry axis of the nebula. Deep narrowband imaging in the light of [NII], [OIII] and [SII], obtained using ACAM on the William Herschel Telescope, has been used to investigate the ionisation structure of Abell 41. Longslit observations of the H-alpha and [NII] emission were obtained using the Manchester Echelle Spectrometer on the 2.1-m San Pedro M\'artir Telescope. These spectra, combined with the narrowband imagery, were used to develop a spatio-kinematical model of [NII] emission from Abell 41. The best fitting model reveals Abell 41 to have a waisted, bipolar structure with an expansion velocity of ~40km\s at the waist. The symmetry axis of the model nebula is within 5\degr of perpendicular to the orbital plane of the central binary system. This provides strong evidence that the close-binary system, MT Ser, has directly affected the shaping of its nebula, Abell 41. Although the theoretical link between bipolar planetary nebulae and binary central stars is long established, this nebula is only the second to have this link, between nebular symmetry axis and binary plane, proved observationally.Comment: 7 pages, 6 figures, Accepted for publication in MNRA