Oliver Newton

I'm a Postdoctoral Fellow at the Center for Theoretical Physics at the Polish Academy of Sciences working with Prof. Wojciech Hellwing. My research focuses on using 'small scale' structure (i.e. galaxies smaller than our own) to infer the properties of Dark Matter. At CFT, I am working in the newly established COLAB project looking at the effects of cosmic environment on small-scale structures in the Milky Way and Local Group.

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 to study for my PhD at the Institute for Computational Cosmology (ICC). I completed this in August 2019 under the supervision of Prof. Adrian Jenkins and Prof. Carlos Frenk.

In October that year, I began postdoctoral research in Lyon, France working with Prof. Noam Libeskind on the HESTIA suite of Local Group analogue simulations. At the conclusion of 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.

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.

Research

Primarily, my research relates to the dwarf galaxies of the Milky Way and Local Group 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, we believe that it makes up ∼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., 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.

Newton et al., 2022, MNRAS, 514(03), 3612

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

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  • Address

    Center for Theoretical Physics
    Polish Academy of Sciences
    Al. Lotników 32
    02-668 Warsaw
    Poland

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