Journal: Astronomy and Astrophysics

  • Publication
    Ubiquitous hundred-Gauss magnetic fields in solar spicules
    Aims: We aim to study the magnetic field in solar spicules using high-resolution spectropolarimetric observations in the Ca II 8542 Å line obtained with the...
  • Publication
    Ubiquitous quiet-Sun jets
    Context. IMaX/Sunrise has recently reported the temporal evolution of highly dynamic and strongly Doppler shifted Stokes V signals in the quiet Sun. Aims: We...
  • Publication
    Ultra-cool dwarfs: new discoveries, proper motions, and improved spectral typing from SDSS and 2MASS photometric colors
    Aims: We try to identify ultra-cool dwarfs from the seventh Data Release of the Sloan Digital Sky Survey (SDSS DR7) with SDSS i-z and r-z colors. We also obtain...
  • Publication
    Ultra-deep imaging of NGC 1052-DF2 and NGC 1052-DF4 to unravel their origins
    A number of scenarios have been proposed to explain the low velocity dispersion (and hence possible absence of dark matter) of the low surface brightness...
  • Publication
    UltraCompCAT: A comprehensive catalogue of ultra-compact and short orbital period X-ray binaries
    Ultracompact X-ray binaries (UCXBs) are a distinctive but elusive family of low-mass X-ray binaries (LMXBs) characterised by their tight orbits and degenerate...
  • Publication
    Uncertainties in the solar photospheric oxygen abundance
    Aims: The purpose of this work is to better understand the confidence limits of the photospheric solar oxygen abundance derived from three-dimensional models...
  • Publication
    Uncertainty-aware blob detection with an application to integrated-light stellar population recoveries
    Context. Blob detection is a common problem in astronomy. One example is in stellar population modelling, where the distribution of stellar ages and...
  • Publication
    Uncovering the true periods of the young sub-Neptunes orbiting TOI-2076
    Context. TOI-2076 is a transiting three-planet system of sub-Neptunes orbiting a bright (G = 8.9 mag), young (340 ± 80 Myr) K-type star. Although a validated...
  • Publication
    Understanding internetwork magnetic fields as determined from visible and infrared spectral lines
    We present numerical experiments aimed at understanding why near-infrared observations systematically deliver weak magnetic fields in the internetwork, whereas...