[Astro] [CAPT] Postdoc opportunity in modified gravity and subsequent tests in galaxies

[Alfonso Aragon-salamanca (staff)]

Dear all,

See below announcement of a postdoc opportunity that may interest both Astronomers and Particle Cosmologists.

Best wishes,

Alfonso


Alfonso Aragón-Salamanca
Professor of Astronomy

School of Physics and Astronomy
University of Nottingham
Room B106b, Centre for Astronomy and Particle Theory
University Park
Nottingham, NG7 2RD, UK

+44 (0) 115 95 16230 | alfonso.aragon at nottingham.ac.uk<mailto:alfonso.aragon at nottingham.ac.uk>
URL: http://nottingham.ac.uk/physics/people/alfonso.aragon
General teaching enquiries physics-teaching at nottingham.ac.uk<mailto:physics-teaching at nottingham.ac.uk>

From: Annie Robin via sdss4-general <sdss4-general at sdss.org>
Sent: 15 December 2025 11:33
To: sdss4-general at sdss.org; Gillot Jonathan <jonathan.gillot at femto-st.fr>
Subject: [sdss4-general 4582] Postdoc opportunity


Dear colleagues,

We emphasize the opportunity of financial support for a postdoc position in Besançon (France) to work on models of modified gravity and subsequent tests in galaxies. Below is the description of the subject. The position will be for 2 years.

In the ΛCDM framework, modelling the rotational velocities of galaxies relies on dark matter. There are many candidates (WIMPs, axions, scalar fields, etc.), but no particles have been detected to date. Alternatives propose modifying Newton's laws at low accelerations (~10^(-10) m.s2)   (i.e. MOND) to account for the observed rotation curves. However, these models often use ad hoc interpolation functions and acceleration scales to deviate from the Newtonian regime. A recent model - the quantum modified inertia (QMI) - introduces a new principle of dynamics with minimal acceleration of quantum origin developed within the framework of special relativity (https://arxiv.org/abs/2507.11524).

Based on this principle, a simple code has been developped that successfully recover several spiral rotation curves, and even the rising curve of dwarf galaxies that, in the LCDM theory, are difficult to explain. The post-doc work will be to improve the code to apply it to various galaxy types.

Furthermore, it has been recently shown that the radial acceleration relation (RAR, see http://arxiv.org/abs/1610.08981) proposed to support the MOND theories was excluded by the Cassini probe trajectory (https://arxiv.org/abs/2401.04796). One possibility for reconciling the RAR deduced from the SPARC galaxy data set (used by Lelli et al) with Cassini constraint is to refine the stellar-to-mass ratios. The postdoc will explore the sensitivity of the RAR to the stellar-to-mass ratio at different wavelengths, using different hypotheses of Galactic evolution (IMF, star formation history, dust content...) through population synthesis modelling with existing codes.

At the present time the RAR is based mainly on one sample of galaxies (the SPARC sample). The postdoc will look for and explore other data sets that could confirm or rule it out, therefore constraining the modified gravitation or inertia model, or modified it such that it best explains all available galaxy types, from massive galaxies to dwarfs, as well as the Cassini constraint.



The candidate should have his/her PHD for less than 10 years and provide a summary of his/her career paths, a List of 5 principal publications, and main skills and expertises. The financial support will be covered by the Region Bourgogne-Franche-Comté after a dedicated application form due by early january.

Interested candidates can contact Annie Robin (annie.robin at obs-besancon.fr<mailto:annie.robin at obs-besancon.fr>) and Jonathan Gillot (jonathan.gillot at femto-st.fr<mailto:jonathan.gillot at femto-st.fr>). Applications are requested before 28th december.

Best regards,



--

Annie C. Robin

Institut Utinam, OSU Theta Franche-Comté-Bourgogne, France
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