Astrophysical: Spiral galaxies

  • Publication
    Density bounding of giant HII regions and the ionization of the diffuse interstellar medium
    Three different types of evidence are presented in favour of the hypothesis that the HII regions in disk galaxies with H-alpha luminosities greater than a...
  • Publication
    Density wave triggered star formation in grand design spirals
    In normal spiral galaxies the arms are the main sites for star formation. This is the cause of their optical contrast compared with the rest of the disc. The...
  • Publication
    Departures from axial symmetry, and starburst activity, in the bulge of NGC 4736
    Evidence for circumnuclear starbursts in spiral galaxies can take the form of a blue excess near the nucleus, but more frequently (because of dust extinction) H...
  • Publication
    Diagnostics of the underlying physical differences between flocculent and well-defined spiral galaxies
    From published catalogs, basic physical properties including diameters, masses, and neutral hydrogen contents of spiral galaxies have been studied as a function...
  • News
    Differences between the discs of active and non-active galaxies detected for the first time
    A study led by researchers at the Instituto de Astrofísica de Canarias (IAC), making comparison between the discs of several pairs of spiral galaxies, active...
  • Publication
    Differential efficiency of massive star formation in NGC 628
    The efficiency ratio of massive star formation in the arms of the spiral NGC 628 to that in the interarm region has been determined from the sizes and positions...
  • Publication
    Disk Galaxies Are Self-similar: The Universality of the H I-to-Halo Mass Ratio for Isolated Disks
    Observed scaling relations in galaxies between baryons and dark matter global properties are key to shed light on the process of galaxy formation and on the...
  • Publication
    Distribution, sizes, and luminosity function of the HII regions in NGC 4321
    From H-alpha CCD observations taken with the 4.2-m William Herschel Telescope, a catalog of 456 H II regions of the inner zone of the spiral galaxy NGC 4321 has...
  • Publication
    Dust extinction in NGC 4594, the Sombrero galaxy
    The extinction law in the well-defined dust lane of the Sombrero galaxy, NGC 4594, was studied. In the R, I, J, H, and K bands good agreement is found between...