News from the Dark 11

29 sept. 2026, 09:15 → 1 oct. 2026, 18:30 Europe/Paris

Amphithéâtre Bloch (IPhT-Saclay)

Julien Lavalle (LUPM - Montpellier), Francesca CALORE, Benoit Famaey (CNRS Observatoire astronomique de Strasbourg), Emmanuel Nezri (Laboratoire d'Astrophysique de Marseille), Patrick VALAGEAS (CEA Saclay)

This mini-workshop is aimed at gathering a few experts from different fields (mostly theoretical cosmology, galactic dynamics, [astro]particle physics) to discuss current progress, issues, and prospects in the understanding of dark matter (DM). The focus is mostly on how different DM scenarios imprint galactic and subgalactic scales, and how these can in turn be used to discriminate among several classes of DM candidates. This is directly linked to the small-scale tensions the LCDM paradigm is currently facing, which could be related either to baryonic physics, specific dark matter properties, or both.

Participation is on invitation, and the philosophy may be summarized as: interactive, friendly, unveil the dust under carpets, share knowledge or ideas,  trigger collaborative work. This is the ninth edition of this workshop series (previous editions: 2013, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024, 2025).

The 2026 meeting will take place at the IPHT-Saclay from Sept. 29 to Oct. 1st.

Invited speakers include S. Ando, P. Brax, M. Buschmann, M. Cirelli, S. Codis, R. Tito D'Agnolo, P. Das, C. Delaunay, F. D'Eramo, D. Elbaz, R. Errani, J. Fangzhou, Y. Génolini, R. Ibata, H. Kim, J. Lopez-Sanchez, S. Nagesh, M-O. Olea Romacho, J. Peñarrubia, W. Qin, T. Spieksma, and others TBC.

This meeting is partly supported by IPhT, LUPM, CNRS-INSU (AT-PEM and AT-CG), the ANR under contract ANR-18-CE31-0006 (the GaDaMa project), and by the ERC project GREATDIGINTHESKY.

mar. 29 septembre

09:15 Welcome coffee

1 Introduction

Orateurs: Francis Bernardeau (IPhT Saclay), Julien Lavalle (LUPM - Montpellier), Patrick VALAGEAS (CEA Saclay)

2 Indirect searches for dark matter

Orateur: Marco CIRELLI (LPTHE Jussieu CNRS)

3 Axion mass from cosmo lattice simulations

Orateur: Malte Buschmann

4 Axions at the meV mass scale

Orateur: Francesco D'Eramo

12:15 Lunch break

5 Tabletop experiments to detect axions

Orateur: Raffaele DAgnolo

6 Detection of ULDM with gravitational and non-gravitational methods

Orateur: Hyungjin Kim

7 Matter influence on large-scale scalar dynamics

Orateur: philippe brax (IPHT Saclay)

16:00 Coffee break

8 New physics searches with atomic spectroscopy

Orateur: Cedric DELAUNAY (LAPTH)

9 Black hole binaries and dark matter

Orateur: Thomas Spieksma

mer. 30 septembre

10 Simulations of ultralight dark matter

Orateur: Jessica N. Lopez-Sanchez

11 Wave optics and dark matter subhalos

Orateur: Shin'ichiro Ando

10:45 Coffee break

12 Impact of Galactic dark matter objects on pulsar timing

Orateur: Camille Libourel

13 Probing the dark matter substructure with dynamical heating effects

Orateur: Jorge Peñarrubia

12:30 Lunch break

14 Collisional dynamics of stars and dark matter in ultra-faint galaxies

Orateur: Raphaël Errani

15 Probing primordial magnetic fields with small-scale structures of dark matter

Orateur: Maria-Olalla Olea-Romacho

16 Pros and cons of SIDM

Orateur: Fangzhou Jiang

16:00 Coffee break

17 Insights/new questions on early star/galaxy formation from the James Webb

Orateur: David Elbaz

18 Little red dots beyond standard scenarios

Orateur: Wenzer Qin

19:30 Social dinner

jeu. 1 octobre

19 Large-scale structures and the nature of dark matter

Orateur: Sandrine Codis (LCEG/AIM/CNRS)

10:15 Coffee break

20 Revealing dark matter halos from kinematic tracers

Orateur: Payel Das

21 Dynamics of galactic disks

Orateur: Kerwann Tep

12:15 Lunch break

22 Stellar streams as dark matter tracers

Orateurs: Anirudh Shankar, Rodrigo Ibata (Observatoire Astronomique de Strasbourg)

23 MOND Part I: Modified gravity on small scales

Orateur: Benoit Famaey (CNRS Observatoire astronomique de Strasbourg)

24 MOND Part II: MOND vs. CDM dynamics

Orateur: Srikant Nagesh

25 Concluding remarks (TBC)

Orateur: James Binney