1,463 research outputs found
Molecules in Bipolar Outflows
Bipolar outflows constitute some of the best laboratories to study shock
chemistry in the interstellar medium. A number of molecular species have their
abundance enhanced by several orders of magnitude in the outflow gas, likely as
a combined result of dust mantle disruption and high temperature gas chemistry,
and therefore become sensitive indicators of the physical changes taking place
in the shock. Identifying these species and understanding their chemical
behavior is therefore of high interest both to chemical studies and to our
understanding of the star-formation process. Here we review some of the recent
progress in the study of the molecular composition of bipolar outflows, with
emphasis in the tracers most relevant for shock chemistry. As we discuss, there
has been rapid progress both in characterizing the molecular composition of
certain outflows as well as in modeling the chemical processes likely involved.
However, a number of limitations still affect our understanding of outflow
chemistry. These include a very limited statistical approach in the
observations and a dependence of the models on plane-parallel shocks, which
cannot reproduce the observed wing morphology of the lines. We finish our
contribution by discussing the chemistry of the so-called extremely high
velocity component, which seems different from the rest of the outflow and may
originate in the wind from the very vicinity of the protostar.Comment: 15 pages, 7 figures. Contribution to the IAU Conference "The
Molecular Universe" held in Toledo in June 201
IRAM-PdBI Observations of Binary Protostars I: The Hierarchical System SVS13 in NGC1333
We present millimeter interferometric observations of the young stellar
object SVS13 in NCG1333 in the N2H+(1-0) line and at 1.4 and 3mm dust
continuum, using the IRAM Plateau de Bure interferometer. The results are
complemented by infrared data from the Spitzer Space Telescope. The millimeter
dust continuum images resolve four sources (A, B, C, and VLA3) in SVS13. With
the dust continuum images, we derive gas masses of 0.2-1.1 M_sun for the
sources. N2H+(1-0) line emission is detected and spatially associated with the
dust continuum sources B and VLA3. The observed mean line width is ~0.48 km/s
and the estimated virial mass is ~0.7 M_sun. By simultaneously fitting the
seven hyperfine line components of N2H+, we derive the velocity field and find
a symmetric velocity gradient of about 28 km/s/pc across sources B and VLA3,
which could be explained by core rotation. The velocity field suggests that
sources B and VLA3 are forming a physically bound protobinary system embedded
in a common N2H+ core. Spitzer images show mid-infrared emission from sources A
and C, which is spatially associated with the mm dust continuum emission. No
infrared emission is detected from source B, implying that the source is deeply
embedded. Based on the morphologies and velocity structure, we propose a
hierarchical fragmentation picture for SVS13 where the three sources (A, B, and
C) were formed by initial fragmentation of a filamentary prestellar core, while
the protobinary system (sources B and VLA3) was formed by rotational
fragmentation of a single collapsing sub-core.Comment: 26 pages, 9 figures, accepted by Ap
Sophus Lie
ArtÃculo sobre el centenario de Marius Sophus LieFac. de Ciencias MatemáticasTRUEpu
FilosofÃa del amor en «El Cantar de los Cantares»
Conferencia pronunciada en el Salón de Actos de la Comunidad Israelita
de Madrid, el 26 de marzo de 1974, por el Prof. Angel RodrÃguez Bachiller, ilustre filósofo y sugestivo conferenciante, el cual, sobre el cañamazo de una de las
numerosas teorÃas excogitadas en la exégesis del libro, aun a sabiendas de que
quizá no es hoy la más seguida, ha bordado con !lingular maestrÃa y excelente argumentación un estudio denso y ameno.
El lector que desee alguna información sobre exégesis externa del Cantar, entre
la inmensa bibliografÃa en torno a este diminuto libro puede ver, p. e., revista
Sefarad 1 (1941), pp. 364-366; el Manual de Historia de la Literatura Hebrea por
David Gonzalo Maeso, I parte, cap. XII, pp. 143-150; o alguna de las numerosas
Introducciones a la Sda. Escritura, Diccionarios bÃblicos o grandes Enciclopedias
judaicas.
Advertimos asimismo que ateniéndose al tÃtulo mismo del libro en la Biblia y
al uso tradicional, emplea el conferenciante la expresión "canto de Salomón".
(D.G.M.
Germay (R. H.J.): intégration par approximations successives des équations aux derivées partielles (Reseña)
La reseña corresponde a un artÃculo publicado en: Extrait des Mémories de la Soc. Royale des Sciences de Liège, 3ª serie, tomo XII, 1924. Fasc. de 42 págs.Fac. de Ciencias MatemáticasTRUEpu
Curso de topologÃa
Crónica. Real Academia de Ciencias Exactas, FÃsicas y Naturales. Fundación del Conde de Cartagena. Cátedra de Matemática (curso de topologÃa). Conferencias del Prof. T. R. Bachiller.Fac. de Ciencias MatemáticasTRUEpu
Conjuntos cerrados no densos
Glosario matemático. Discusión sobre: Hobson (E. H.): The theory of junctions of a real variable and the theory of Fourier’s series. Cambridge University Press. Edición de 1907 y tomo 1.* de la de 1921.Fac. de Ciencias MatemáticasTRUEpu
Fueter (Dr. R.): Vorlesungen lÃber die singulüren nioduln and die Komplexe Multipllkatlon der elliptlschen Funktionen.
Reseña del artÃculo: Fueter (Dr. R.): Vorlesungen lÃber die singulüren moduln and die Komplexe
Multipllkatlon der elliptlschen Funktionen.—Erster Teil., VI, 142 S. mit. 16 Figuren im Text. B. G. Teubner. Leipzig-Berlin, 1924.Fac. de Ciencias MatemáticasTRUEpu
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