Nicolas Martin

Poste de chercheur post-doctoral - Observatoire astronomique de Strasbourg L’observatoire astronomique de Strasbourg (ObAS), en collaboration avec l’institut thématique interdisciplinaire IRMIA++ (Recherche en mathématiques, interactions et applications) de l’université de S...

Un poste de fellow post-doctoral est ouvert à l'Observatoire astronomique de Strasbourg dans le cadre de l'IRMIA++ :
astro.unistra.fr/fr/2025/10/3...

L’archéologie galactique avec les courants d’étoiles Un spectacle proposé dans le cadre des Echappées inattendues du CNRS : embarquez pour un voyage immersif depuis l’orbite terrestre jusqu’aux confins de la Voie lactée. Découvrez comment les astronomes...

La semaine prochaine, @nfmartin1980.bsky.social et Claire Guillaume feront un spectacle sur l'archéologie galactique avec les courants d’étoiles, au Planétarium du Jardin des Sciences de @unistra.fr, avec les Echappées inattendues @cnrs.fr les 4 et 7/10.
jardin-sciences.unistra.fr/programmatio...

NSF-DOE Vera C. Rubin Observatory Observations of Interstellar Comet 3I/ATLAS (C/2025 N1) We report on the observation and measurement of astrometry, photometry, morphology, and activity of the interstellar object 3I/ATLAS, also designated C/2025 N1 (ATLAS), with the NSF-DOE Vera C. Rubin ...

It's paper day! The first science paper with data from @vrubinobs.bsky.social's survey camera, the mighty LSSTCam, is a VERY quick turnaround of Rubin's observations thus far of interstellar comet 3I/ATLAS. ☄️
Chandler et al., submitted 🔭
A 🧵

Happy to announce that the line-detector.oca.eu website is now online!
It allows the user to select the stellar type, [M/H], λ- range, and resolving power and the page returns:
-purity of the line and minimum S/N required to detect it.
-interactive plot to identify the lines in the spectra

[Atelier philo-sciences] "Temps des humains, temps des étoiles", #Médiathèque de #Cronenbourg, mercredi 23/04. Avec Nicolas Martin, astrophysicien à @obsstrasbourg.bsky.social , la philosophe Élise Tourte et la facilitatrice graphique Violaine Leroy. Retour en images.
@agencerecherche.bsky.social

C'est parti !
@euclid-france.bsky.social

Atelier Philo-Sciences "Temps des humains, temps des étoiles" à la médiathèque Meinau, samedi 15/03 à 10:30 avec @nfmartin1980.bsky.social, en partenariat avec @cnrs-alsace.bsky.social et les médiathèques de @strasbourg-eu.bsky.social :
www.alsace.cnrs.fr/fr/evenement...

This review was an absolute joy to write. Thank you Amandine and @runningastronomer.bsky.social ! :)

A model image of what our home galaxy, the Milky Way, might look like face-on: as viewed from above the disc of the galaxy, with its spiral arms and bulge in full view. In the centre of the galaxy, the bulge shines as a hazy oval, emitting a faint golden gleam. Starting at the central bulge, several glistening spiral arms coil outwards, creating a perfectly circle-shaped spiral. They give the impression of someone having sprinkled pastel purple glitter on the pitch-black background, in the shape of sparkling, curled-up snakes.

A model image of what our home galaxy, the Milky Way, might look like edge-on, against a pitch-black backdrop. The Milky Way’s disc appears in the centre of the image, as a thin, dark-brown line spanning from left to right, with the hint of a wave in it. The line appears to be etched into a thin glowing layer of silver sand, that makes it look as if it was drawn with a coloured pencil on coarse paper. The bulge of the galaxy sits like a glowing, see-through pearl in the shape of a sphere in the centre of this brown line

The ESA #Gaia mission has delivered the best Milky Way maps to date and taken its last starlight before spacecraft retirement 🔭

www.esa.int/Science_Expl...

Prix de thèse pour Jakub Podgorný - Observatoire astronomique de Strasbourg Jakub Podgorný, qui a soutenu en décembre 2023 sa thèse effectuée en partenariat entre l’Observatoire astronomique de Strasbourg et la République Tchèque (Prague), vient d’obtenir le prestigieux prix ...

Jakub Podgorný, qui effectué sa thèse effectuée à l’Observatoire astronomique de Strasbourg @unistra.fr, vient d’obtenir le prestigieux prix national des thèses de doctorat en sciences naturelles en République Tchèque. Félicitations !
astro.unistra.fr/fr/2024/12/0...

Archéologie galactique : les antiquités de l'espace Pourquoi sonder les premières étoiles et galaxies de l’univers ? Que reste-t-il à comprendre sur leur formation et leur évolution et les mécanismes guidant leur diverses structures ? Comment les astro...

C’est déjà arrivé ! 😂
Ici : www.radiofrance.fr/francecultur...

En effet, c’est @nicomartinfc.bsky.social dont Fragile/s sort en cette rentrée. 😉

Archéologie galactique : aux origines de notre Voie lactée À quoi ressemblait notre galaxie archaïque ? Comment s’est formée la Voie lactée et quelles sont les péripéties qu’elle a traversées ? Quelles ont été les collisions avec d’autres galaxies et quelles ...

Notre collègue @nfmartin1980.bsky.social était invité de @franceinter.bsky.social pour parler d'archéologie galactique.
www.radiofrance.fr/franceinter/...

Archéologie galactique : aux origines de notre Voie lactée A quoi ressemblait notre galaxie archaïque ? Comment s’est formée la Voie lactée et quelles sont les péripéties qu’elle a traversées ? Quelles ont été les collisions avec d’autres galaxies et quelles ...

J’étais aujourd’hui sur @franceinter.bsky.social pour La Terre au Carré où nous avons discuté archéologie galactique avec ma collègue Alejandra Recio-Blanco.
Un moment agréable d’échange !

www.radiofrance.fr/franceinter/...

Hello there! Are you on the job market? Do you love astrophysics? Then how about applying for one of our 3 open Research Fellow positions at the University of Surrey? One of them is with me! Find and study dwarf galaxies with Michelle! 🔭🧪 jobs.surrey.ac.uk/Vacancy.aspx...

Very happy to be visiting the Royal Observatory of Edinburgh today and giving a talk about the low-metallicity Milky Way this afternoon. And Scottish weather didn’t disappoint this morning!

Yay!!! 🥳

👋
Some root to the name + RA + Dec is a very sensible way to name things! I’ll stand by it! Now, sure, if the mask making code truncates that to root + RA degrees and the field is a few arcmin on the side, yeah, that’s… a problem… 😰

Gaia's brightest very metal-poor (VMP) stars: A metallicity... Context. Gaia DR3 has offered the scientific community a remarkable dataset of approximately one million spectra acquired with the Radial Velocity Spectrometer (RVS) in the Calcium II triplet...

Very happy to share my new paper on arxiv: arxiv.org/abs/2309.06137 releasing a catalogue of spectroscopic metallicities of VMP stars using the amazing Gaia DR3 RVS spectra. Did you know that there exists a lot of archival VMP spectra out there with no published parameters?

Still looks better than my “metal-poo star” in a recent draft… 🤣

Very proud of this work, a huge collaborative effort from the Pristine team! It's great to finally see it out in the wild 🥳🤩🔭

Thanks! 😀

And If course I’m very numb so I forgot to link to the actual paper 🙄. Here it is: https://arxiv.org/abs/2308.01344

And thank you to our amazing colleagues in Pristine and beyond. Esp my co-PI & co-first author Else Starkenburg, Zhen Yuan, Morgan Fouesneau, and @ankeaa.bsky.social, who all worked particularly hard for this paper, and all the colleagues from Pristine. It's wonderful to be working with you all!

None of this would have been possible without the wonderful staff at CFHT that has been observing Pristine for us since 2015 and the beautiful work of the Gaia consortium that has published truly magnificent data. THANK YOU!

But there's so many more things to do with these metallicity catalogues. The Pristine team has a few projects in the works, but we're also very excited to see what the community does with those! 😍
And there's so much more in the paper too (30 pages… sorry…)

Finally, we also have fun with the catalogue. 😁
Ever seen how the shape of the Milky Way changes with metallicity? Here it is!
The transition from the flat metal-rich disk to the rounder, spheroid-shaped meta-poor halo is just super obvious in these maps.

All the catalogues are already available at a temp site before acceptance (https://seafile.unistra.fr/d/ee0c0f05719d4368bcbb/) for anyone to play with. Sooo many good candidate stars with [Fe/H]<-2.0 (>120k with very strict quality cuts) or [Fe/H]<-3.0 (~3k with the same quality).

But that's not all! We use this opportunity to provide the community with the much higher signal-to-noise Pristine metallicities for all of those 219M stars that we already observed in Pristine survey. That's our first data release and includes 3M even higher quality [Fe/H]!

Here, the comparison with literature high-resolution spectroscopic metallicities (Pristine is on the y axis). We get reliable metallicities down to at least [Fe/H]=-3.5. A difficult regime for most other efforts to get metallicities out of the Gaia data for so many stars.