llustration of the evolution and the mechanisms acting on an isolated self-interacting dark matter halo, which becomes bound to a host system over time.
We recently investigated the evolution of satellite halos with self-interacting dark matter using a new simulation framework that analytically describes the host halo. All the details can be found in the study led by David Klemmer. arxiv.org/abs/2603.19362
Illustration of the interaction between two numerical particles to model dark matter scattering.
Today, we are making our SIDM simulation code (OpenGadget3) available to the community! You can find all the details in our paper. If you are interested, please contact me.
arxiv.org/abs/2603.10107
Plot of the density as a function of radius for a simulation of a dark matter satellite halo. The density profile is shown at several times together with observed densities from ultra-faint dwarfs.
Could the ultra-faint faint dwarfs of the Milky Way undergo gravothermal collapse driven by self-interactions of dark matter? As we show in our recent paper, it appears plausible that many of them are in the collapse phase.
arxiv.org/abs/2603.04508
Plot of the projected logarithmic density slope as a function of the projected enclosed mass, shown for five different radii. The isothermal jeans model and an N-body simulation are compared with each other.
The isothermal Jeans model for self-interacting dark matter halos works surprisingly well during the gravothermal collapse phase, as we found in a study led by Shubo Li.
arxiv.org/abs/2603.01772
View of a building at the Donostia International Physics Centre. The logo with the letters DIPC can be seen on the façade.
I am delighted to have started this week as a Feodor Lynen Fellow of the Alexander von Humboldt Foundation (@humboldt-foundation.de) at the Donostia International Physics Centre (@dipcehu.bsky.social) in San Sebastián, working in Raúl Angulo's group.
Today, I had the pleasure to review the state of the art in simulations of self-interacting dark matter at the SIDM workshop in Valencia.
indico.ific.uv.es/event/7815/
To collapse or not to collapse? A study led by my student Yashraj Patil on the evolution of a self-interacting dark matter halo with two dark matter species.
arxiv.org/abs/2506.06272
Paper day! Today we have our latest study on how to accurately simulate gravothermally collapsing dark matter halos on arXiv!
arxiv.org/abs/2506.06269
Today, we present the first N-body simulations of a self-interacting dark matter spike around a supermassive black hole in our paper led by V. Sabarish. https://arxiv.org/abs/2505.14779
I presented this work a few weeks ago at UCLA Dark Matter 2025: moritzfischer.world/DM25/
Finally out! Our paper with the first N-body simulations of dark matter-baryon interactions is now on arXiv. arxiv.org/abs/2504.12393
How can we simulate realistic self-interacting dark matter models with large- and small-angle scattering? Check out the new study led by our student Cenanda Arido! https://arxiv.org/abs/2410.07175
Delighted to see that the work led by S. Yang with new constraints on velocity-dependent self-interactions of dark matter got accepted! https://arxiv.org/abs/2305.05067
Happy that our paper on numerical issues in simulations of collapsing self-interacting dark matter halos got accepted. https://arxiv.org/abs/2403.00739
It was a pleasure to discuss dark matter research at the KITP conference "Cosmic Signals of Dark Matter Physics: New Synergies"! I am happy that my talk about signatures of the angular dependence of dark matter self-interactions is available on YouTube. https://youtu.be/wmtmhLMgSG8
How does dynamical friction change when dark matter has self-interactions? Learn about it in our new paper by Laura Sagunski and myself. https://arxiv.org/abs/2405.19392
SIDM can make subhalos in galaxy clusters more compact, but in a different way than one would naively expect, as shown in our study led by A. Ragagnin, using full physics zoom-in simulations. https://arxiv.org/abs/2404.01383
Just compiled a plot of various constraints on the dark matter self-interaction cross-section for my upcoming talks.
Two and four weeks ago, two papers appeared on arXiv investigating numerical problems in N-body simulations of collapsing SIDM halos. We join them with our study explaining the causes of energy conservation errors in simulations of the late collapse phase. https://arxiv.org/abs/2403.00739
In our second paper today, led by V. Sabarish, we find that the effects of velocity-dependent self-interactions are more pronounced in the late stages of merging galaxy clusters than shortly after the first passage of the clusters through each other. https://arxiv.org/abs/2310.07769
Today on arXiv, our qualitative study of velocity-dependent self-interactions. We find that a strong velocity dependence can diversify the halo population regardless of the angular dependence of the scattering. https://arxiv.org/abs/2310.07750
I am honoured to have received the Best Paper Award from the Cluster of Excellence Quantum Universe today. www.qu.uni-hamburg.de/research/highlights/23-0...
Our new website for our research on self-interacting dark matter is online. Check it out! https://darkium.org
Paper day! We have studied the role of the ICM in merging galaxy clusters with SIDM: 1. the presence of the ICM enhances DM-galaxy offset, 2. the position of the shock front combined with the galaxy positions could be an interesting probe of DM. https://arxiv.org/abs/2302.07882