Not Refereed

 

Recent Submissions

  • X-Shooting ULLYSES: Massive Stars at Low Metallicity
    Armagh Observatory and Planetarium, UK; Department of Physics & Astronomy, University of Sheffield, UK; Space Telescope Science Institute, Baltimore, USA; Centre for Astrobiology (CSIC-INTA), Torrejón de Ardoz, Madrid, Spain; Montpellier Universe and Particles Laboratory, Montpellier University, France; Las Campanas Observatory, Carnegie Observatories, Chile; Institute for Physics and Astronomy, University of Potsdam, Germany; Department of Physics, University of Montreal, Canada; Penn State Scranton, Dunmore, PA, USA; Astronomy Centre, Heidelberg University, Germany; et al. (The Messenger, 2024-03-01)
    The Hubble Space Telescope has devoted 500 orbits to observing 250 massive stars with low metallicity in the ultraviolet (UV) range within the framework of the ULLYSES program. The X-Shooting ULLYSES (XShootU) project enhances the legacy value of this UV dataset by providing high-quality optical and near-infrared spectra, which are acquired using the wide-wavelength- coverage X-shooter spectrograph at ESO's Very Large Telescope. XShootU emphasises the importance of combining UV with optical spectra for the consistent determination of key stellar parameters such as effective temperature, surface gravity, luminosity, abundances, and wind characteristics including mass-loss rates as a function of metallicity. Since uncertainties in these parameters have implications across various branches of astrophysics, the data and modelling generated by the XShootU project are poised to significantly advance our understanding of massive stars at low metallicity. This is particularly crucial for confidently interpreting James Webb Space Telescope (JWST) data of the earliest stellar generations, making XShootU a unique resource for comprehending individual spectra of low-metallicity stars.

  • The Gravitational-wave Optical Transient Observer (GOTO)
    The Univ. of Sheffield (United Kingdom); The Univ. of Warwick (United Kingdom); Monash Univ. (Australia); Univ. of Leicester (United Kingdom); Armagh Observatory (United Kingdom); National Astronomical Research Institute of Thailand (Thailand); Instituto de Astrofísica de Canarias (Spain); University of Turku (Finland); The Univ. of Manchester (United Kingdom); Univ. of Portsmouth (United Kingdom); et al. (Ground-based and Airborne Telescopes VIII, 2020-12-01)
    The Gravitational-wave Optical Transient Observer (GOTO) is a wide-field telescope project focused on detecting optical counterparts to gravitational-wave sources. GOTO uses arrays of 40 cm unit telescopes (UTs) on a shared robotic mount, which scales to provide large fields of view in a cost-effective manner. A complete GOTO mount uses 8 unit telescopes to give an overall field of view of 40 square degrees, and can reach a depth of 20th magnitude in three minutes. The GOTO-4 prototype was inaugurated with 4 unit telescopes in 2017 on La Palma, and was upgraded to a full 8-telescope array in 2020. A second 8-UT mount will be installed on La Palma in early 2021, and another GOTO node with two more mount systems is planned for a southern site in Australia. When complete, each mount will be networked to form a robotic, dual-hemisphere observatory, which will survey the entire visible sky every few nights and enable rapid follow-up detections of transient sources.

  • The Gravitational-wave Optical Transient Observer (GOTO)
    The Univ. of Sheffield (United Kingdom); The Univ. of Warwick (United Kingdom); Monash Univ. (Australia); Univ. of Leicester (United Kingdom); Armagh Observatory & Planetarium (United Kingdom); National Astronomical Research Institute of Thailand (Thailand); Univ. of Turku (Finland); The Univ. of Manchester (United Kingdom); Univ. of Portsmouth (United Kingdom); Instituto de Astrofísica de Canarias (Spain); et al. (Ground-based and Airborne Telescopes IX, 2022-08-01)
    The Gravitational-wave Optical Transient Observer (GOTO) is a wide-field telescope project focused on detecting optical counterparts to gravitational-wave sources. Each GOTO robotic mount holds eight 40 cm telescopes, giving an overall field of view of 40 square degrees. As of 2022 the first two GOTO mounts have been commissioned at the Roque de los Muchachos Observatory on La Palma, Canary Islands, and construction of the second node with two additional 8-telescope mounts has begin at Siding Spring Observatory in New South Wales, Australia. Once fully operational each GOTO mount will be networked to form a robotic, multi-site observatory, which will survey the entire visible sky every two nights and enable rapid follow-up detections of transient sources.

  • Polarimetry as a Tool to Study Multi-Dimensional Winds and Disks
    Armagh Observatory, College Hill, Armagh, Armagh, BT61 9DG, Norn Iron; Vink, J. S. (The B[e] Phenomenon: Forty Years of Studies, 2017-02-01)
    I start with a discussion of spherical winds and small-scale clumping, before continuing with various theories that have been proposed to predict how mass loss depends on stellar rotation - both in terms of wind strength, as well as the latitudinal dependence of the wind. This very issue is crucial for our general understanding of angular momentum evolution in massive stars, and the B[e] phenomenon in particular. I then discuss the tool of linear polarimetry that allows us to probe the difference between polar and equatorial mass loss, allowing us to test B[e] and related disk formation theories.

  • The VLT-FLAMES Tarantula Survey
    Armagh Observatory, College Hill, BT61 9DG, Armagh, Northern Ireland; ATC, Royal Observatory Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ, UK; ARC, School of Mathematics and Physics, QUB, Belfast BT7 1NN, UK; Institute of Astrophysics, KU Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium; Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH, UK; -; Vink, Jorick S.; Evans, C. J.; Bestenlehner, J.; McEvoy, C.; et al. (The Lives and Death-Throes of Massive Stars, 2017-11-01)
    We present a number of notable results from the VLT-FLAMES Tarantula Survey (VFTS), an ESO Large Program during which we obtained multi-epoch medium-resolution optical spectroscopy of a very large sample of over 800 massive stars in the 30 Doradus region of the Large Magellanic Cloud (LMC). This unprecedented data-set has enabled us to address some key questions regarding atmospheres and winds, as well as the evolution of (very) massive stars. Here we focus on O-type runaways, the width of the main sequence, and the mass-loss rates for (very) massive stars. We also provide indications for the presence of a top-heavy initial mass function (IMF) in 30 Dor.

  • MOONS: The New Multi-Object Spectrograph for the VLT
    ESO; STFC, UK Astronomy Technology Centre, Royal Observatory Edinburgh, UK; Cavendish Laboratory, University of Cambridge, UK; Instituto de Astrofísica e Ciências do Espaço and Departamento de Física, Faculdade de Ciências, Universidade de Lisboa, Portugal; GEPI, Observatoire de Paris, PSL University, CNRS, France; Department of Physics, ETH Zurich, Switzerland; INAF-Osservatorio Astrofisico di Arcetri, Florence, Italy; Department of Astronomy, University of Geneva, Versoix, Switzerland; Pontificia Universidad Católica de Chile, Santiago, Chile; Department of Physics, University of Oxford, UK; et al. (The Messenger, 2020-06-01)
    MOONS is the new Multi-Object Optical and Near-infrared Spectrograph currently under construction for the Very Large Telescope (VLT) at ESO. This remarkable instrument combines, for the first time, the collecting power of an 8-m telescope, 1000 fibres with individual robotic positioners, and both low- and high-resolution simultaneous spectral coverage across the 0.64-1.8 μm wavelength range. This facility will provide the astronomical community with a powerful, world-leading instrument able to serve a wide range of Galactic, extragalactic and cosmological studies. Construction is now proceeding full steam ahead and this overview article presents some of the science goals and the technical description of the MOONS instrument. More detailed information on the MOONS surveys is provided in the other dedicated articles in this Messenger issue.