PADC

OntoPortal-Astro: Un catalogue d'artefact sémantique pour l'astronomie

Stephane Erard — 2025-12-05T10:16:53Z

Clément Jonquet (INRAE)
Baptiste Cecconi (ObsParis)

Lundi 15 dec 2025 à 15h, Salle du Levant à Paris

Nous présentons l'outil communautaire OntoPortal initialement développé par Stanford (USA) et plus récemment par l'INRAE (Montpellier), avec leur portail AgroPortal. Cet outil est un catalogue d'artefact sémantique (un terme générique pour des vocabulaires, thésaurus, ou ontologies), avec des fonctionnalités avancées pour explorer, annoter, partager des concepts et des ontologies. La plateforme inclut aussi une interface interoperable (API) pour une interaction sous forme de script, ainsi qu'un outil d'évaluation des critère FAIR (Findable Accessible, Interoperable and Reusable) appliqués aux ontologies. Avec l'aide de l'équipe de l'INRAE à Montpellier, nous avons installé un serveur dédié à l'astronomie au sens large: https://ontoportal-astro.eu, qui liste déjà les vocabulaires de l'IVOA (astronomie) et dont le rôle est de partager et croiser les ontologies et vocabulaires des différentes composantes de l'astronomie: héliophysique, planétologie, astronomie, astrophysique, astroparticules, cosmologie physique atomique et moléculaire, modélisation, etc. Nous présenterons la plateforme Ontoportal/AgroPortal de l'INRAE et notre nouvelle plateforme ontoportal-astro.eu.

The Occultation Portal at Observatory of Paris

Stephane Erard — 2025-11-18T22:38:38Z

Mercredi 26 novembre 2025, 16h30 Salle du Chateau à Meudon (and on-line)
Séminaire LIRA/PADC/ProAM

The Occultation Portal at the Paris Observatory (OPOP): Migration and Institutional Integration
Yücel Kılıc

The Occultation Portal (OP) is a scientific infrastructure originally developed within the ERC Lucky Star collaboration with groups from Paris, Meudon, Granada and Rio, and is now actively used in ongoing occultation-focused projects such as ACROSS and GaiaMoons. It supports the full workflow of stellar occultation studies, including prediction and campaign coordination, as well as the ingestion, validation, and long-term archiving of both video-based and photometric observations. With upcoming surveys such as LSST and future Gaia releases expected to significantly increase the number of observable events, ensuring the scalability and operational robustness of the OP has become essential.
Over the past six months, the Occultation Portal has been migrated to the PADC/DIO infrastructure of the Paris Observatory and has undergone a broad technical modernisation. This work includes the implementation of a full MD5-based data-integrity framework, GDPR-compliant handling of user and observatory information, a redesigned user-registration and moderation workflow, an upgraded publication system with ADS-powered metadata ingestion linking scientific outputs to OP events and archived data, and extended prediction and mapping tools. Together, these developments greatly enhance the platform's long-term stability and ensure that the OP continues to serve as a reliable infrastructure for advancing stellar occultation science.

Recording on astrotube:
https://astrotube.obspm.fr/w/mCqqQrJ5h9ZFpMMA6exxkL

Markus Demleitner on DaCHS

Stephane Erard — 2024-02-26T19:05:18Z

9h30 salle Denisse le jeudi 29 Février
Unsing DaCHS for images and spectra, with practical examples

- Seminars

Commencer l'intégration et le déploiement continus avec Gitlab CI/CD

Stephane Erard — 2021-08-26T15:46:50Z

par Sonny Lion (CDD-IR, LESIA)

GitLab est un outil permettant de gérer de bout en bout un projet de développement. En plus du traditionnel dépôt de code source, Gitlab offre de nombreuses fonctionnalités comme un système de suivi de bugs (ou issues), un hébergement de pages web statiques (HTML/CSS/JS), un Wiki et surtout la possibilité de faire de l'intégration et du déploiement/distribution continus.

L'intégration continue permet d'exécuter automatiquement un ensemble de scripts pour tester et valider les modifications apportées au code source et de s'assurer que tout fonctionne avant de fusionner ces modifications avec la branche principale et de les déployer en production.

La distribution continue et le déploiement continu poussent encore plus loin l'automatisation en ajoutant une ou plusieurs étapes visant par exemple à:
– déployer automatiquement les mises à jour sur l'environnement de production;
– ou encore envoyer la dernière version de votre package sur votre hébergeur favori (Pypi, npm, Docker Hub, etc.).

Ces automatisations permettent de détecter les bugs et les erreurs plus facilement tout en garantissant que tout code déployé en production a été validé et est conforme à vos exigences.

L'idée de cette présentation est de voir comment construire un pipeline d'intégration et de déploiement continus avec GitLab en partant d'un projet contenant quelques fichiers sources ainsi que quelques tests et en détaillant chaque étape du processus.

Diapos
Video

Discovery of intermediate-mass black holes with the Virtual Observatory

Stephane Erard — 2019-02-12T17:23:44Z

Par Igor Chilingarian (CfA, Harvard, USA)

Nearly every massive galaxy harbors a supermassive black hole (SMBH) in its nucleus. SMBH masses are millions to billions of solar mass, and they correlate with properties of spheroids of their host galaxies. While the SMBH growth channels, mergers, and gas accretion are well established, their origin remains uncertain: they could have emerged either from massive “seeds” (10⁵–10⁶ M⊙) formed by direct collapse of gas clouds in the early universe or from smaller (100 M⊙) BHs, end products of first stars. The latter channel would leave behind numerous intermediate-mass BHs (IMBHs, 10²–10⁵ M⊙). Although many IMBH candidates have been identified, none are accepted as definitive; thus, their very existence is still debated. Using data mining in wide-field sky surveys and applying dedicated analysis to archival and follow-up optical spectra, we identified a sample of 305 IMBH candidates having masses 3×10⁴ Mȯ < M_BH< 2×10⁵ Mȯ , which reside in galaxy centers and are accreting gas that creates characteristic signatures of a type I active galactic nucleus (AGN). We confirmed the AGN nature of 10 sources (including five previously known objects that validate our method) by detecting the X-ray emission from their accretion disks, thus defining the first bona fide sample of IMBHs in galactic nuclei. All IMBH host galaxies possess small bulges and sit on the low-mass extension of the MBH—Mbulge scaling relation, suggesting that they must have experienced very few if any major mergers over their lifetime. The very existence of nuclear IMBHs supports the stellar-mass seed scenario of the massive BH formation.

The Las Campanas Stellar Library: an essential tool to interpret NIR spectra of galaxies

Stephane Erard — 2017-02-20T16:42:00Z

Par Igor Chilingarian (CfA, Cambridge, USA)

We present the most comprehensive up-to-date intermediate resolution (R=6500) stellar library, which covers the entire near-infrared wavelength range (0.83 to 2.5um). It contains spectra of 1000+ stars across the HR diagram collected with the FIRE spectrograph at the 6.5m Magellan Baade telescope processed with a dedicated bright source data reduction pipeline. Among others, our library includes about 250 AGB stars, 50 LMC/SMC stars, and also a sample of chemically peculiar stars. We have about 150 stars in common with the X-Shooter Spectral Library project which will allow us to perform cross-checks, assess the data quality and pin down potential systematic problems. By the start of the JWST mission we plan to produce a new generation of stellar population models which will enable the extragalactic community to interpret nearby galaxy spectra in the NIR and analyze unresolved stellar populations in a manner similar to the one used in the optical domain. The spectral resolution will be sufficient to study internal kinematics and stellar content of dwarf galaxies and nuclear star clusters in nearby galaxies. For about 650 stars, we built complete optical-to-NIR spectra at R=6500 using re-calibrated optical spectra from INDO-US and UVES-POP stellar libraries.

ARTEMIX - Alma RemoTE MIning eXperiment

Stephane Erard — 2017-01-11T16:35:00Z

par Philippe SALOME (LERMA)

Even if not yet in full operation mode, the ALMA observatory has already delivered huge amounts of data. Those data are accessible to download via the ALMA science archive portal from their parent project id. We present here ARTEMIX (Alma RemoTE MIning eXperiment), a development from the Paris Observatory that aims at exploring new tools for metadata and datacube remote visualisation. ARTEMIX does not reprocess the calibrated data. It is thought as a collection of display facilities which aim is to ease the definition of trans-project subsamples. Future developments, like automated subsample selection via higher-level data analysis are possible, but require the access to fully imaged data-cubes that are not provided yet.

Le projet Gaia-GBOT : un exemple d'utilisation des outils OV

Florence HENRY (webmestre) — 2016-11-01T10:57:00Z

Par Christophe Barache & Sébastien Bouquillon (SYRTE)

Pour permettre à la mission Gaia d'atteindre ses objectifs astrométriques, un suivi optique terrestre du satellite a été imaginé et mis en place. Ainsi, depuis son lancement le 19 Décembre 2013, des observations quotidiennes de la sonde sont effectuées et traitées par le groupe de travail Gaia-GBOT (Ground Based Optical Tracking). Les observations sont réalisées à l'aide des caméras CCD du "VLT Survey Telesope" de l'ESO sur le Cerro Paranal au Chili et du "Liverpool Telescope" situé sur l'île de La Palma aux Canaries.

Durant ce séminaire, je présenterai les différentes activités liées à ce service d'observation (SO1) au SyRTE qui comprennent : la préparation des observations, le traitement astrométrique semi-automatique des images, le processus de validation des résultats ainsi que leur mise en base. Pour chaque étape, je m'attacherai à montrer la manière dont les outils de l'observatoire virtuel y sont utilisés et leurs intérêts.

Collaborative research or doing real science online

Florence HENRY (webmestre) — 2009-06-22T14:50:00Z

Presented by Ivan Zolotukhin (Sternberg Astronomical Institute) and Igor Chilingarian (Observatoire de Paris-Meudon / Sternberg Astronomical Institute)

Following the Virtual Observatory getting mature more and more science cases arise from its usage. We would like to present one more live demonstration of what can be done in the field of galactic astronomy having knowledge of recent surveys, specifically tackling the well-known problem of optical identification of x-ray sources discovered in Galactic Plane. We will show that in the frame of entirely new way of VO-powered collaborative communications that allow (remote) researchers to do scientific analysis together simultaneously. The talk is aimed at the broad audience interested not only in given particular subject of astronomy but also at those who seeks for new opportunities that VO offers to researchers in their everyday work.