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: Grey scale representation of the probability density distribution of the location of 575 Galactic stars in the spectroscopic Hertzsprung-Russell diagram. Three empirical borderlines between densely populated regions and empty regions are d
    The distribution of stars in the Hertzsprung-Russell diagram narrates their evolutionary history and directly assesses their properties. Placing stars in this diagram however requires the knowledge of their distances and interstellar extinctions, which are often poorly known for Galactic stars. The spectroscopic Hertzsprung-Russell diagram (sHRD) tells similar evolutionary tales, but is independent of distance and extinction measurements. Based on spectroscopically derived effective temperatures and gravities of almost 600 stars, we derive for the first time the observational distribution of
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  • Figure 1:  Trailed intensity image showing the orbital evolution of two emission lines in MWC 656. Fe II 4,583 Å  is formed in the equatorial disc of the Be star while  He II 4,686 Å  arises from gas encircling the companion black hole.
    Stellar-mass black holes have all been discovered through X-ray emission, which arises from the accretion of gas from their binary companions (this gas is either stripped from low-mass stars or supplied as winds from massive ones). Binary evolution models also predict the existence of black holes accreting from the equatorial envelope of rapidly spinning Be-type stars (stars of the Be type are hot blue irregular variables showing characteristic spectral emission lines of hydrogen).  Of the ~80 Be X-ray binaries known in the Galaxy, however, only pulsating neutron stars have been found as
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  • Figure CaptionLeft: SDSS image of Mrk 709 (RGB=zrg), which appears to be a pair of interacting dwarf galaxies. We designate the northern and southern galaxies Mrk 709 N and Mrk 709 S. A logarithmic scaling is used to show extended emission. The white circ
    The incidence and properties of present-day dwarf galaxies hosting massive black holes (BHs) can provide important constraints on the origin of high-redshift BH seeds. Here we present high-resolution X-ray and radio observations of the low-metallicity, star-forming, dwarf-galaxy system Mrk 709 with the Chandra X-ray Observatory and the Karl G. Jansky Very Large Array (VLA). These data reveal spatially coincident hard X-ray and radio point sources with luminosities suggesting the presence of an accreting massive BH (M BH ∼ 10 5−7 M ⊙). Based on imaging from the Sloan Digital Sky Survey (SDSS)
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  • Picture of GHαFaS interferometer taken once the instrument is assembled in the Nasmyth focuss of the WHT, in La Palma.
    We have obtained two-dimensional velocity fields in the ionized gas of a set of eight double-barred galaxies, at high spatial and spectral resolution, using their Hα emission fields measured with a scanning Fabry-Perot spectrometer. Using the technique by which phase reversals in the non-circular motion indicate a radius of corotation, taking advantage of the high angular and velocity resolution we have obtained the corotation radii and the pattern speeds of both the major bar and the small central bar in each of the galaxies; there are few such measurements in the literature. Our results
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  • Figure Caption: LIRIS (red dots) and NIRSPEC (black line) spectra of Pleiades proper motion candidates. The NIRSPEC spectrum of Calar 21 is normalized to the K-band LIRIS spectrum. The left panel illustrates the comparison of the Pleiades data with field,
    We report on the near-infrared low-resolution spectroscopy and red optical (Z-band) photometry of seven proper-motion, very low-mass substellar member candidates of the Pleiades cluster with magnitudes in the interval J=17.5-20.8 and K=16.1-18.5 mag. Spectra were acquired for six objects with the LIRIS and NIRSPEC instruments mounted on the 4.2-m WHT and the 10-m Keck II telescopes. Z-band images of two of the faintest candidates were collected with ACAM/WHT. The new data confirm the low temperatures of all seven Pleiades candidates. From the imaging observations, we find extremely red Z-J
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  • Caption: Compilation of the values of λ, measured via the RM effect, as a function of the host star effective temperature (see: http://www.astro.keele.ac.uk/jkt/tepcat/rossiter.html).HAT-P-18b is shown as a filled blue dot. For the two objects marked with
    The measurement of the Rossiter-McLaughlin effect for transiting exoplanetsplaces constraints on the orientation of the orbital axis with respect to the stellar spin axis, which can shed light on the mechanisms shaping the orbital configuration of planetary systems. Here we present the interesting case of the Saturn-mass planet HAT-P-18b, which orbits one of the coolest stars for which the Rossiter-McLaughlin effect has been measured so far. We acquired a spectroscopic time-series, spanning a full transit, with the HARPS-N spectrograph mounted at the TNG telescope. The very precise radial
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