7–13 Sept 2025
Hermitage Hotel, Isola D'Elba
Europe/Rome timezone

Mapping Gravity with Extragalactic Streams and Citizen Science

11 Sept 2025, 12:20
40m
Hermitage Hotel, Isola D'Elba

Hermitage Hotel, Isola D'Elba

57037 Portoferraio Isola d’Elba (Li) Italy
Talk Dark Matter (Its nature: Theory, Observations, Detection, Production at accelerators) Morning session 4

Speaker

Nathaniel Starkman (MIT Kavli Institute for Astrophysics and Space Research)

Description

Wide-field surveys like Euclid mark a new era of extragalactic stellar stream studies, with exciting applications in measuring baryon and dark matter distributions, and connecting galaxies to their cosmological context.
I present results from a pilot study combining Euclid imaging with Zooniverse classifications to detect and analyze streams. We use projected stream morphologies to constrain the shape and barycenter of each host galaxy’s potential, jointly probing baryonic and dark matter distributions. These inferences complement lensing, with sensitivity to halo geometry on tens of kpc scales. The method enables both stacked, population-level constraints on halo triaxiality and barycenters, and individual-halo inference on the same. Already, we find promising agreement with ΛCDM predictions. Our program will identify thousands of streams, enabling precise constraints on halo shapes and barycenters across large samples and redshifts, offering a new dynamical test of dark structures.

References Nibauer et al 2023 -- 10.3847/1538-4357/ace9bc

Author

Nathaniel Starkman (MIT Kavli Institute for Astrophysics and Space Research)

Co-authors

Mr Jake Nibauer (Princeton) Jo Bovy (University of Toronto) Lina Necib (MIT) Dr Michael Walmsley (University of Toronto) Prof. Sarah Pearson (University of Copenhagen) Mr Sirui Wu (University of Copenhagen)

Presentation materials

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