News

This section includes scientific and technological news from the IAC and its Observatories, as well as press releases on scientific and technological results, astronomical events, educational projects, outreach activities and institutional events.

  • Figure caption: Left : (FUV − NUV) versus (NUV − [3.6]) color-color diagram. Morphological types are represented by color (see legend). We define the blue and red sequence by dividing the plot into two regions and fitting a least-squares 1-D polynomial (a
    We obtained GALEX FUV, NUV, and Spitzer/IRAC 3.6 µm photometry for >2000 galaxies, available for 90% of the S4G sample. We find a very tight "GALEX Blue Sequence (GBS)" in the (FUV − NUV) versus (NUV − [3.6]) color-color diagram which is populated by irregular and spiral galaxies, and is mainly driven by changes in the formation timescale (τ ) and a degeneracy between τ and dust reddening. The tightness of the GBS provides an unprecedented way of identifying starforming galaxies and objects that are just evolving to (or from) what we call the "GALEX Green Valley (GGV)". At the red end of the
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  • Caption: Artist illustration of the central core of the planetary nebula Henize 2-428. Stars are not to scale. Credit: Gabriel Pérez, SMM (IAC).
    The planetary nebula (PN) stage is the ultimate fate of stars with mass 1 to 8 solar masses (M⊙). The origin of their complex morphologies is poorly understood, although several mechanisms involving binary interaction have been proposed. In close binary systems, the orbital separation is short enough for the primary star to overfill its Roche lobe as it expands during the Asymptotic Giant Branch (AGB) phase. The excess material ends up forming a common-envelope (CE) surrounding both stars. Drag forces would then result in the envelope being ejected into a bipolar PN whose equator is
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  • Figure caption. Left panel: Image of the planet at 100 AU from the dwarf star VHS 1256.This false colour image has been put together from images in the Y J and K bands takenwith the VISTA telescope of the European Southern Observatory, in the VISTA Hemisp
    In a search for common proper motion companions using the VISTA Hemisphere Survey (VHS) and the 2MASS catalogs we have identi fied a very red (J-Ks = 2.47 mag) late-L dwarf companion of a previously unrecognized M dwarf VHSJ125601.92-125723.9 (hereafter VHS1256-1257), located at a projected angular separation of 8.06"+/-0.03". In this work we present a suite of astrometric, photometric, and spectroscopic observations of this new pair in an effort to confirm the companionship and characterize the components. From low-resolution (R_130-600) optical and near-infrared spectroscopy we classi fied
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  • Evolution of the volume occupied by the ejecta (left panels) and the shock top pole velocity (right panels). Panels (a) and (b), (c) and (d), (e) and (f) show the results of the calculations when the explosion occurs at Zoff = 0 pc, 1 pc, and 2 pc from th
    Our arguments deal with the early evolution of Galactic globular clusters and show why only a few of the supernovae products were retained within globular clusters and only in the most massive cases (M>106 solar masses) while less massive clusters were not contaminated at all by supernovae. Here we show that supernova blast waves evolving in a steep density gradient undergo blowout and end up discharging their energy and metals into the medium surrounding the clusters. This inhibits the dispersal and the contamination of the gas left over from a first stellar generation. Only the ejecta from
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  • Figure caption: Profiles of the broad 4428 Å band (left panel) and of the 5780 Å feature (right panel) towards Tc 1 central star (black) and average of two sight lines to the nebular position on either side of the nebula. In both panels, the dashed blue l
    Identification of the carriers of the diffuse interstellar bands (DIBs) has been very elusive since the beginning of the last century. Differentcomplex carbon-based molecules - e.g., carbon chains, polycyclicaromatic hydrocarbons (PAHs), and fullerenes - have been proposed asDIB's carriers. If the DIBs arise from large gas phase molecules, such as PAHs and fullerenes, then they are also expected to be present in other carbon-rich space environments like circumstellar shells around evolved stars. Diffuse circumstellar bands (DCBs) in absorption have been unsuccessfully studied for more than
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