Oliver Newton

I'm a Marie Skłodowska–Curie Fellow in the Astrophysics Research Group at the University of Surrey, UK. My research focuses on using galaxies as tools to probe the nature of the Universe. At Surrey I am leading the CWEBDWARFS project connecting the physical mechanisms underpinning galaxy evolution with their large-scale cosmological environments.

About me

I grew up in the East Midlands in the UK and pursued my BSc and MPhys in Physics at the University of Warwick. After a year of work in industry I moved to Durham University where I completed my PhD at the Institute for Computational Cosmology under the supervision of Prof. Adrian Jenkins and Prof. Carlos Frenk.

In October 2019 I began postdoctoral research in Lyon, France working with Dr. Noam Libeskind on the HESTIA suite of Local Group simulations. After this I undertook a short-term position at the Astrophysics Research Institute at Liverpool John Moores University working with Prof. Rob Crain to study how the merger history of L* galaxies affects the disruption of their Globular Cluster populations. In September 2022 I moved to the Center for Theoretical Physics of the Polish Academy of Sciences to work with Dr. Wojciech Hellwing looking at the effects of cosmic environment on small-scale structures.

Hobbies

Out of the office I enjoy playing music with a variety of bands and orchestras and have done so from an early age. In that time I've had the opportunity to perform in venues across the UK and Europe, including multiple appearances in London's Royal Albert Hall. I was also incredibly fortunate to establish and run the UniBrass Foundation as a trustee during its first six years. I also try my hand at running and baking (not at the same time!).

Research

Primarily, my research relates to dwarf galaxies as visible probes of dark matter structure. In the standard cosmological model (known as ΛCDM) dark matter is hugely influential in shaping the evolution of the Universe; indeed, it comprises as much as ∼85% of all matter. However, we still don't know what it is. No dark matter (DM) particle has been seen directly in any detectors, so we are left to try to infer some of its properties from a mix of astrophysical observations of galaxies and advanced computer simulations.

You can see a full list of my publications here:

Satellite galaxies of the Milky Way

One major prediction of ΛCDM is that the present-day Milky Way is embedded in a DM halo that is rich with thousands of smaller DM clumps, or substructures. Many — but not all — of these are expected to host faint satellite galaxies. Observational campaigns to detect some of these elusive objects have been carried out already, with further surveys planned to commence operations in the next few years. While this work is being undertaken, we can use observations from partial surveys of the sky to infer the total number and luminosity function of satellite galaxies around the Milky Way.

Newton et al., 2018, MNRAS, 479(3), 2853-2870

Warm Dark Matter

Although extremely successful, ΛCDM is not the only viable description of the Universe. One class of models known as 'warm' DM predicts that DM particles have higher thermal velocities when DM haloes form. This allows them to escape shallow gravitational potential wells and prevents the DM forming into haloes below a certain mass. In some models this cut-off is at the scale of dwarf galaxies. This makes the Milky Way satellite system useful to constrain the DM properties, as a model can be feasible only if it produces enough substructure around the Milky Way to host the observed population of satellite galaxies.

Newton et al., 2025, MNRAS, 541(4), 3713–3727
Newton et al., 2021, JCAP, 2021(08), 62
Enzi, Murgia, Newton et al., 2021, MNRAS, 506(4), 5848–5862

Discovery of Hermeian haloes

During the assembly of the Local Group many low-mass DM haloes interact with the Milky Way or Andromeda. This induces tidal effects in the low-mass haloes that reorganise their internal structure and remove mass from their outer regions. As a result, their DM concentrates towards the centre, making them promising targets to detect DM annihilation signals. 'Hermeian' haloes are a new class of field halo that passed through the Milky Way and Andromeda. They have a characteristic spatial distribution that could make them easier to identify in observational searches, and show promise as sources of DM annihilation signals. They also play an important role as conduits of matter transfer between the Milky Way and Andromeda.

Osipova et al., 2023, PDU, 42, 101328
Newton et al., 2022, MNRAS, 514(03), 3612–3625

Undiscovered ultra-diffuse galaxies in the Local Group

Ultra-diffuse galaxies (UDGs) are similar to the brightest satellite galaxies of the Milky Way but are many times larger. This makes them very diffuse and difficult to observe, even with state-of-the-art instruments and efficient algorithms to search observational data. Nonetheless, the effort to find them is important because a large fraction of galaxies are expected to be ultra-diffuse and they could be useful tests of cosmological models. We show that there is a population of UDGs in the Local Group awaiting discovery. Excitingly, some could already be in data collected by the Sloan Digital Sky Survey or Dark Energy Survey.

Newton et al., 2023, ApJL, 946(2), L37

Galaxy–environment connection

Observations show that galaxy properties are sensitive to their environment; however, its precise role in their evolution remains unclear. Globular clusters are a variety of ancient star cluster that form very early in the lifetime of the Universe, enabling us to probe conditions shortly after stars began to form. Coincident with this early star formation the cosmic web begins to affect the evolution of early low-mass galaxies. Thus, the properties of globular clusters and satellite galaxies are intrinsically connected to the large-scale environment we observe today. We find that globular clusters in massive galaxies are sensitive to the merger ratio of mergers experienced by their host galaxy, which can be affected by the cosmological environment, and that the abundance and properties of DM substructures also depend on cosmological environment.

Newton et al., 2025, MNRAS, 542(2), 591–607
Hunde, Newton et al., 2025, A&A, 700, A65

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  • Address

    Surrey Space Centre
    University of Surrey
    Guildford
    Surrey
    GU2 7XH
    UK

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