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.

  • Caption figure 1: Electron density v. radius de of an HII region, in logarithmic units, for the HII regions in the spiral galaxy M51, showing the relation between these two parameters ( i.e. the electron density varies as the inverse square root of the ra
    Using images of the Advanced Camera for Surveys" of the Hubble SpaceTelescope we have analyzed the global physical parameters of thepopulations of HII regions in two galaxies: M51 and NGC 4449. M51 is a large spiral, in which we have measured and catalogued the Halpha luminosities, the radii, and the positions of more than 2000 of its HIIregions, while NGC 4449 is a dwarf irregular, in which we have catalogued over 200 HII regions. From these measurements we have obtained the mean electron densities, and have derived two simple but powerful relations. The electron density n_e of an HII
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  • Figure Caption: Optical bar fraction of strong (solid black line) and weak+strong (dashedblue line) as a function of the galaxy absolute magnitude in r band (left panel)and galaxy mass (right panel). Red points and black circles represent the strong and w
    In this work we present a recent study of the bar fraction in the ComaCluster galaxies based on a sample of ~190 galaxies selected from theSloan Digital Sky  Survey Data Release 6 and observed with the Hubble Space Telescope (HST)  Advanced  Camera for Survey  (ACS).The unprecedented resolution of the HST-ACS  images allows us  to explore the presence of bars, detected by visual classification, throughout luminosity range of 9 mag (-23 < Mr < -14), permitting us to study th poor known region  of dwarf galaxies. We find that  bars are hosted bygalaxies in  a tight range of both  luminosities
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  • Left: comparison of ULAS1350 with the other four known L subdwarfs previously known. Right: Artist view of the orbit and position of ULAS1350 in our Galaxy. As it can be seen from the figure, subdwarfs are located in the halo of our Galaxy.Credits: Nicola
    The Gran Telescopio CANARIAS open new prospects to characterise the oldest population of stars in our Galaxy with the discovery of a cold and distant low-metallicity star A new object with an age of thousands of millions of years and a mass of one tenth of the Sun, placing it at the frontier between low-mass stars and brown dwarfs, has been discovered as the furthest of its class in Milky Way. Nicknamed ULAS1350, this subdwarf could become on of the key element to improve our knowledge on the first steps of the formation of our Galaxy.The team of European astronomers responsible for the
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  • A long-standing issue in solar astrophysics concerns the strength and structure variations with height of the magnetic field in the chromosphere of the quiet Sun. Our empirical knowledge on this issue has remained vague notwithstanding the qualitative information provided by high resolution monochromatic images of the solar atmosphere taken at various wavelengths across strong spectral lines like H-alpha showing a mass of cell-spanning fibrils as a flattened carpet, with upright ones jutting out from network patches. Unfortunately, such images do not provide quantitative information on the
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  • Recent observations of the rotation curve of M31 show a rise of the outer part that cannot be understood in terms of standard dark matter models or perturbations of the galactic disk by M31?s satellites. Here, we propose an explanation of this dynamical feature based on the in?uence of the magnetic ?eld within the thin disk. We have considered standard mass models for the luminous mass distribution, a Navarro?Frenk?White model to describe the dark halo, and we have added up the contribution to the rotation curve of a magnetic ?eld in the disk, which is described by an axisymmetric pattern
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