Autre Publication Scientifique HST Proposal. Cycle 32 Année : 2024

STIS-ISM: STIS ISM Survey in the Milky Way

Annalisa de Cia
  • Fonction : Auteur
Serj Balashev
  • Fonction : Auteur
Paul A. Crowther
  • Fonction : Auteur
Laurent Dalla Pola
  • Fonction : Auteur
Marjorie Decleir
  • Fonction : Auteur
Christopher Evans
  • Fonction : Auteur
Steven R. Federman
  • Fonction : Auteur
Andrew J. Fox
  • Fonction : Auteur
Gonzalo Holgado
  • Fonction : Auteur
Edward B. Jenkins
  • Fonction : Auteur
Christina Konstantopoulou
  • Fonction : Auteur
Daria Kosenko
  • Fonction : Auteur
Varsha Purushottam Kulkarni
  • Fonction : Auteur
Cedric Ledoux
  • Fonction : Auteur
Celine Peroux
  • Fonction : Auteur
Tanita Ramburuth-Hurt
  • Fonction : Auteur
Adam M. Ritchey
  • Fonction : Auteur
Julia Christine Roman-Duval
  • Fonction : Auteur
Sandra Savaglio
  • Fonction : Auteur
Sergio Simon-Diaz
  • Fonction : Auteur
Anna Velichko
  • Fonction : Auteur
Daniel E. Welty
  • Fonction : Auteur
Abel de Burgos Sierra
  • Fonction : Auteur

Résumé

The Interstellar Medium (ISM) is key to the chemical evolution of our Galaxy. Until recently, the metallicity of the neutral ISM could not be measured and was assumed to be perfectly mixed, motivated by Galactic rotation. Today, the chemical properties of the neutral ISM are hotly debated, with some papers claiming the presence of low-metallicity gas due to gas infall on the disk and others measuring solar-metallicity gas, independent of galactocentric distance. Above all, the complexity of the chemical properties of the ISM is becoming striking. About half of the abundance patterns show deviations from the norm, likely caused by the superposition along the sightline of multiple ISM 'clouds' with different chemical properties (metallicity and/or depletion of metals into dust). STIS-ISM aims at observing OB stars in the Galaxy with the main scientific goals of: 1) Measure the cloud-to-cloud variations of metallicity in the neutral ISM along 20 sightlines. This requires highest-resolution spectroscopy covering different metals and we build a dedicated sample to complement existing archival data. The metallicity dispersion has an impact on phenomena related to gas mixing in galaxies. 2) Measure the metallicity gradient in the neutral ISM. This requires mid-resolution spectra of targets at large Galactocentric distances, currently limited to a dozen targets. STIS-ISM will study the ISM along 39 Gaia targets at > 9 kpc from the Galactic Center, an uncharted territory. We will also study the stellar metallicities and compare with the gas. STIS-ISM will leave behind an unparalleled UV legacy, as the high resolution of the STIS spectra will remain unmatched for decades to come.

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Dates et versions

insu-04838854 , version 1 (15-12-2024)

Identifiants

Citer

Annalisa de Cia, Serj Balashev, Paul A. Crowther, Laurent Dalla Pola, Marjorie Decleir, et al.. STIS-ISM: STIS ISM Survey in the Milky Way. 2024, pp.17703. ⟨insu-04838854⟩
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