8,208 research outputs found

    Inner and outer star forming regions over the disks of spiral galaxies. I. Sample characterization

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    Context. The knowledge of abundance distributions is central to understanding the formation and evolution of galaxies. Most of the relations employed for the derivation of gas abundances have so far been derived from observations of outer disk HII regions, despite the known differences between inner and outer regions. Aims. Using integral field spectroscopy (IFS) observations we aim to perform a systematic study and comparison of two inner and outer HII regions samples. The spatial resolution of the IFS, the number of objects and the homogeneity and coherence of the observations allow a complete characterization of the main observational properties and differences of the regions. Methods. We analyzed a sample of 725 inner HII regions and a sample of 671 outer HII regions, all of them detected and extracted from the observations of a sample of 263 nearby, isolated, spiral galaxies observed by the CALIFA survey. Results. We find that inner HII regions show smaller equivalent widths, greater extinction and luminosities, along with greater values of [NII]{\lambda}6583/H{\alpha} and [OII]{\lambda}3727/[OIII]{\lambda}5007 emission-line ratios, indicating higher metallicites and lower ionization parameters. Inner regions have also redder colors and higher photometric and ionizing masses, although Mion/Mphot is slighty higher for the outer regions. Conclusions. This work shows important observational differences between inner and outer HII regions in star forming galaxies not previously studied in detail. These differences indicate that inner regions have more evolved stellar populations and are in a later evolution state with respect to outer regions, which goes in line with the inside-out galaxy formation paradigm.Comment: 16 page

    Deep into the Water Fountains: The case of IRAS 18043-2116

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    (Abridged) The formation of large-scale (hundreds to few thousands of AU) bipolar structures in the circumstellar envelopes (CSEs) of post-Asymptotic Giant Branch (post-AGB) stars is poorly understood. The shape of these structures, traced by emission from fast molecular outflows, suggests that the dynamics at the innermost regions of these CSEs does not depend only on the energy of the radiation field of the central star. Deep into the Water Fountains is an observational project based on the results of programs carried out with three telescope facilities: The Karl G. Jansky Very Large Array (JVLA), The Australia Telescope Compact Array (ATCA), and the Very Large Telescope (SINFONI-VLT). Here we report the results of the observations towards the WF nebula IRAS 18043-2116: Detection of radio continuum emission in the frequency range 1.5GHz - 8.0GHz; H2_{2}O maser spectral features and radio continuum emission detected at 22GHz, and H2_{2} ro-vibrational emission lines detected at the near infrared. The high-velocity H2_{2}O maser spectral features, and the shock-excited H2_{2} emission detected could be produced in molecular layers which are swept up as a consequence of the propagation of a jet-driven wind. Using the derived H2_{2} column density, we estimated a molecular mass-loss rate of the order of 10910^{-9}M_{\odot}yr1^{-1}. On the other hand, if the radio continuum flux detected is generated as a consequence of the propagation of a thermal radio jet, the mass-loss rate associated to the outflowing ionized material is of the order of 105^{-5}M_{\odot}yr1^{-1}. The presence of a rotating disk could be a plausible explanation for the mass-loss rates estimated.Comment: 10 pages, 5 figures. Accepted for publication in A&

    Flux-cutting and flux-transport effects in type-II superconductor slabs in a parallel rotating magnetic field

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    The magnetic response of irreversible type-II superconductor slabs subjected to in-plane rotating magnetic field is investigated by applying the circular, elliptic, extended-elliptic, and rectangular flux-line-cutting critical-state models. Specifically, the models have been applied to explain experiments on a PbBi rotating disk in a fixed magnetic field Ha{\bm H}_a, parallel to the flat surfaces. Here, we have exploited the equivalency of the experimental situation with that of a fixed disk under the action of a parallel magnetic field, rotating in the opposite sense. The effect of both the magnitude HaH_a of the applied magnetic field and its angle of rotation αs\alpha_s upon the magnetization of the superconductor sample is analyzed. When HaH_a is smaller than the penetration field HPH_P, the magnetization components, parallel and perpendicular to Ha{\bm H_a}, oscillate with increasing the rotation angle. On the other hand, if the magnitude of the applied field, HaH_a, is larger than HPH_P, both magnetization components become constant functions of αs\alpha_s at large rotation angles. The evolution of the magnetic induction profiles inside the superconductor is also studied.Comment: 12 pages, 29 figure

    Promotion of Healthy Physical Activity in School Recreation

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    Los autores desean mostrar su agradecimiento al profesorado de Educación Física de los centros participantes por su colaboración, a los equipos directivos de dichos centros por su apoyo y a las familias de los alumnos por autorizar la realización de la investigaciónEl objetivo de este trabajo fue investigar qué medidas se podrían tomar para aumentar los niveles generales de actividad física del alumnado de sexto de Educación Primaria durante los periodos de recreo escolar. Se implementó un programa específico desde el currículum de la asignatura de Educación Física y, después de haber finalizado la aplicación del citado programa, se comprobó los niveles de actividad física. También se realizó una observación pasados treinta días de su finalización, con el fin de comprobar en qué medida se modifican los hábitos de actividad física. El instrumento de recogida de datos fue el podómetro, que los participantes utilizaron durante los periodos de recreo escolar. El análisis de los resultados permite afirmar que la aplicación del programa específico objeto de estudio incide positivamente sobre el incremento del volumen de actividad física que realiza el alumnado en su tiempo libre y que, pasados treinta días desde su aplicación, el alumnado mantiene parte de incremento adquirido, modificando su hábito de actividad durante el recreo escolarThe objective of this work was to investigate what measures could be taken to increase the general levels of physical activity of students in sixth grade of Primary Education during the school breaks. A specific program was implemented from the curriculum of the subject of Physical Education and, after completing its application, physical activity levels were analyzed. In addition, an observation was conducted thirty days after its completion, in order to verify to what extent the habits of physical activity are modified. The instrument of data collection was the pedometer, which the participants used during the periods of school break. The analysis of the results allows affirming that the application of the specific program object of study affects positively on the increase of the volume of physical activity that the students do in their free time and that, after thirty days from its application, the students keep part of this increase acquired, which means a change in their activity habit during school break

    Near IR diffraction-limited integral-field SINFONI spectroscopy of the Circinus galaxy

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    Using the adaptive optics assisted near infrared integral field spectrometer SINFONI on the VLT, we have obtained observations of the Circinus galaxy on parsec scales. The morphologies of the H_2(1-0)S(1) 2.12um and Br_gamma 2.17um emission lines are only slightly different, but their velocity maps are similar and show a gradient along the major axis of the galaxy, consistent with rotation.Since V_rot/sigma is approximately 1 suggests that random motions are also important, it is likely that the lines arise in a rotating spheroid or thickened disk around the AGN. Comparing the Br_gamma flux to the stellar continuum indicates that the star formation in this region began almost 10^8 yr ago. We also detect the [SiVI] 1.96um,[AlIX] 2.04um and [CaVIII] 2.32um coronal lines. In all cases we observe a broad blue wing, indicating the presence of two or more components in the coronal line region. A correlation between the ionisation potential and the asymmetry of the profiles was found for these high excitation species.Comment: 6 pages, 5 figures, Submitted to the Proceedings of the IFS Workshop, Jul 4-8 2005, Durham, Englan

    Chiral transition-metal complexes as Brønsted-acid catalysts for the asymmetric Friedel-Crafts hydroxyalkylation of indoles.

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    The Friedel-Crafts reaction between 3,3,3-trifluoropyruvates and indoles is efficiently catalysed by the iridium complex [(η5-C 5Me5)Ir{(R)-Prophos}(H2O)][SbF 6]2 (1) with up to 84% ee. Experimental data and theoretical calculations support a mechanism involving the Brønsted-acid activation of the pyruvate carbonyl by the protons of the coordinated water molecule in 1. Water is not dissociated during the process and, therefore, the catalytic reaction occurs with no direct interaction between the substrates and the metal. This journal is © the Partner Organisations 2014.The authors acknowledge the Ministerio de Economía y Competitividad (MINECO, Grants CTQ2006-03030/BQU, CTQ2009-10303/BQU, CTQ2011-27033 and Consolider Ingenio 2010 CSD2006-003), Gobierno de Aragón (Grupo Consolidado: Catálisis Homogénea Enantioselectiva), Generalitat de Catalunya (2009SGR0259) and the ICIQ foundation for financial support. A. S. and R. R. acknowledge MINECO for predoctoral fellowships. S. D.-G. acknowledges MINECO for a “Torres Quevedo” contract.Peer Reviewe

    Integral Field Spectroscopy of HH 262: The Spectral Atlas

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    HH 262 is a group of emitting knots displaying an "hour-glass" morphology in the Halpha and [SII] lines, located 3.5' to the northeast of the young stellar object L1551-IRS5, in Taurus. We present new results of the kinematics and physical conditions of HH 262 based on Integral Field Spectroscopy covering a field of 1.5'x3', which includes all the bright knots in HH 262. These data show complex kinematics and significant variations in physical conditions over the mapped region of HH 262 on a spatial scale of <3". A new result derived from the IFS data is the weakness of the [NII] emission (below detection limit in most of the mapped region of HH 262), including the brightest central knots. Our data reinforce the association of HH 262 with the redshifted lobe of the evolved molecular outflow L1551-IRS5. The interaction of this outflow with a younger one, powered by L1551 NE, around the position of HH 262 could give rise to the complex morphology and kinematics of HH 262.Comment: Accepted for publication in MNRA

    Integrated spectra extraction based on signal-to-noise optimization using Integral Field Spectroscopy

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    We propose and explore the potential of a method to extract high signal-to-noise (S/N) integrated spectra related to physical and/or morphological regions on a 2-dimensional field using Integral Field Spectroscopy (IFS) observations by employing an optimization procedure based on either continuum (stellar) or line (nebular) emission features. The optimization method is applied to a set of IFS VLT-VIMOS observations of (U)LIRG galaxies, describing the advantages of the optimization by comparing the results with a fixed-aperture, single spectrum case, and by implementing some statistical tests. We demonstrate that the S/N of the IFS optimized integrated spectra is significantly enhanced when compared with the single aperture unprocessed case. We provide an iterative user-friendly and versatile IDL algorithm that allows the user to spatially integrate spectra following more standard procedures. This is made available to the community as part of the PINGSoft IFS software package.Comment: Accepted for publication in Astronomy & Astrophysics, 12 pages, 7 figure
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