Current Research

Galaxy cluster mergers

The current stage of cosmological structure formation in the universe is the formation and growth of galaxy clusters. Major mergers between these massive clusters of galaxies are a primary growth mechanism of galaxy clusters, so studies of their dynamics can test the paradigm of hierarchical structure formation in the universe. Currently, for a set of galaxy clusters, I'm working with my collaborators to compare multi-wavelength observational data from X-ray, optical, and sub-mm datasets to predictions from hydrodynamical simulations in order to constrain merger dynamics, geometries, and initial parameters. We will then use these galaxy cluster merger population statistics to test the ΛCDM cosmological model.


ICM-SHOX. Paper I: Methodology overview and discovery of a gas--dark matter velocity decoupling in the MACS J0018.5+1626 merger

ICM-SHOX. Paper II: Galaxy cluster sample overview

Past Projects

X-ray emission signatures of galactic feedback in the hot circumgalactic medium: predictions from cosmological hydrodynamical simulations

A Search for the 3.5 keV Line from the Milky Way's Dark Matter Halo with HaloSat

Global X-Ray Properties of the Vela and Puppis A Supernova Remnants

Publications

Full list available on ADS, or see my CV. Highlights:

  1. E.M. Silich, J. Sayers, P.F. Hopkins, et al., “Exploring a cosmic ray inverse-Compton origin to the SZ-to-X-ray pressure deficit in the cool core cluster ZwCl 3146”, 2025, submitted to The Astrophysical Journal.

  2. E.M. Silich, J. ZuHone, E. Bellomi, et al., “X-ray emission signatures of galactic feedback in the hot circumgalactic medium: predictions from cosmological hydrodynamical simulations”, 2025, accepted for publication in The Astrophysical Journal.

  3. E.M. Silich, E. Bellomi, J. Sayers, et al., “ICM-SHOX. Paper II: Galaxy cluster sample overview”, 2024, Proc. of the mm Universe 2023 conference, EPJ Web of conferences, EDP Sciences.

  4. E.M. Silich, E. Bellomi, J. Sayers, et al., “ICM-SHOX. Paper I: Methodology overview and discovery of a gas--dark matter velocity decoupling in the MACS J0018.5+1626 merger”, 2024, The Astrophysical Journal, 968, 74.

  5. E.M. Silich, K. Jahoda, L. Angelini, et al., “A Search for the 3.5 keV Line from the Milky Way’s Dark Matter Halo with HaloSat”, 2021, The Astrophysical Journal, 916, 2.

  6. E.M. Silich, P. Kaaret, A. Zajczyk, et al., “Global X-Ray Properties of the Vela and Puppis A Supernova Remnants”, 2020, The Astronomical Journal, 160, 1.

Outreach

Galaxy Clusters Collide: The Most Energetic Events since the Big Bang

Stargazing lecture (public-level) for Caltech Astro + Q&A panel

Dark Matter Flies Ahead of Normal Matter in Mega Galaxy Cluster Collision

Caltech press release on our recent discovery paper