LERMA UMR8112

Laboratoire d’Études du Rayonnement et de la Matière en Astrophysique et Atmosphères



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VAMDC

by nicolas.moreau@obspm.fr - published on

VAMDC

Virtual Atomic and Molecular Data Centre Consortium


The "Virtual Atomic and Molecular Data Centre Consortium" (VAMDC Consortium) is a worldwide consortium which federates Atomic and Molecular databases through an e-science infrastructure and an organisation to support this activity (http://www.vamdc.org/structure/how-to-join-us/).


About 90% of the inter-connected databases handle data that are used for the interpretation of astronomical spectra and for the modeling in media of many fields of astrophysics. The VAMDC Consortium has connected databases from other fields such as the radiation damage and the plasma communities.


The infrastructure is composed of several key components :

  • The Portal is a central access point to look for data. It provides a graphical user interface where users can build queries that are distributed to all the relevant databases at the same time.
  • The species database is a repository of all the atomic and molecular species available in VAMDC. It is populated by gathering daily the chemical species available from each database composing the infrastructure. The species database provides a fast and convenient way to discover where data are located.
  • Each database in the infrastructure is queryable through a web service. They are registered in the VAMDC registry


As a major actor in the field of atomic and molecular physics, the LERMA laboratory is a central element in both the governance and the technical maintenance and evolution of the infrastructure. A team of a senior astronomer and 3 software engineers is involved on different aspects :

  • Marie-Lise Dubernet Tuckey (Astronomer) : current chair of the board of director, scientific coordination.
  • Yaye Awa Ba (computer engineer) : development of the Spectcol software and the Basecol VAMDC node, web manager of the VAMDC website
  • Nicolas Moreau (computer engineer) : development of the VAMDC portal and species database, evolution of standards (convergence with IVOA standards), interface with node managers, co-chair of the technical board
  • Carlo-Maria Zwolf (computer engineer ) : executive director of VAMDC, development of the VAMDC querystore, co-chair of Group of European Data Experts in the Research Data Alliance (RDA) and co-chair of the Federation Identity Management Interest Group in the RDA

Séminaires à venir

Vendredi 15 novembre 2019, 14h00
Salle de l'atelier, Paris
Excitation mechanisms in the intracluster filaments around the Brightest Cluster Galaxies
Fiorella POLLES
LERMA
résumé :
In the center of galaxy clusters lie giant elliptical galaxies, the Brightest Cluster galaxies (BCGs). These galaxies are often surrounded by a system of filaments (e.g. Salomé & Combes 2003) that emit in a wide range of wavelengths, illustrating the multi-phase nature of these streams. Many of these filaments do not have strong on-going star formation and the photoionization by stellar emission cannot reproduce their emission (Johnstone et al. 2007): what is preventing these structures to create stars and what heating mech- anisms are involved, are still open questions. I have investigated cosmic rays and X-rays as likely heating sources, combining multi-wavelength line emission (?23 lines: from optical to far-infrared) with Cloudy models (Polles et al in prep.). I have fully constrained the model of the ionized phase combining for the first time optical-to-infrared emission and self-consistent multi-phase models, pushing the analysis to the molecular phase on three off-nuclear regions of NGC 1275, the central giant elliptical galaxy of the Perseus Cluster. We showed that using X-ray emission as the main heating sources, all of the ionized line emission can be reproduced. We found that to reproduce [OI]63?m line, a small filling factor of the photodissociation phase is necessary. We also showed that adding an additional dense phase or an extra pressure component is required to robustly re- produce the H2 line emission.
 
Vendredi 29 novembre 2019, 14h00
Salle de l'atelier, Paris
The size of galaxies in the era of ultra-deep imaging
Nushkia CHAMBA
Instituto de Astrofisica de Canarias
résumé :
While the effective radius is a robust parameter, its use to
characterise galaxy sizes has provided a counter-intuitive definition of
what the actual extent of a galaxy is. Current deep imaging therefore
offers a unique opportunity to critically review the convention that the
size of a galaxy is its effective radius and rethink how one best
measures the extent of galaxies using a physically motivated parameter.
We introduce a new definition of galaxy size based on the gas density
threshold for star formation in galaxies. Remarkably, our new size
definition not only captures what the human visual system identifies as
the edge of a galaxy, but also dramatically decreases the scatter in the
stellar mass - size plane by a factor of three. Our size parameter
unifies galaxies spanning five orders of magnitude in stellar mass on a
single mass-size relationship. To demonstrate the implications of our
results, we show that ultra-diffuse galaxies have the same sizes as
regular dwarfs when a size indicator that describes the global structure
of galaxies is used. This work may be extended for larger samples of
galaxies using upcoming wide, deep imaging surveys.
 
Vendredi 6 décembre 2019, 14h00
Salle de l'atelier, Paris
Is accretion-driven turbulence a key process for galaxy growth ?
Pierre GUILLARD
IAP
 
Vendredi 13 décembre 2019, 14h00
Salle de l'atelier, Paris
Falsifying the concordance of cosmology with the large-scale structures
Benjamin L'HUILLIER
Yonsei University, Seoul
 
Vendredi 24 janvier 2020, 14h00
Salle de l'atelier, Paris
The accretion-ejection connection in planet-forming disks. New perspectives from high angular resolution observations
Benoît TABONE
Leiden
 
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