Research
My research focuses on understanding the physical mechanisms driving cosmic acceleration and the growth of structure in the Universe, by confronting theoretically well-motivated models with data from cosmological surveys.
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I develop numerical and statistical tools to test dark energy, modified gravity, and dark matter scenarios, examining their imprints on observables such as Baryon Acoustic Oscillations, the non-linear matter power spectrum, and galaxy pairwise motions.
Pairwise velocities
Pairwise velocities quantify the typical relative motion of galaxy pairs as a function of their separation, encoding how gravity pulls structures together on different scales. In my project, I use simulations and theory to model these mean pairwise peculiar velocities down to sub‑megaparsec scales, then apply the resulting framework to observational data to extract additional cosmological information that is inaccessible to standard clustering or lensing analyses.
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Beyond LCDM models
My research on beyond‑ΛCDM cosmology develops and tests theoretically motivated extensions to the standard model of the Universe, including dynamical dark energy and modified gravity, and explores their observational signatures across large‑scale structure and the cosmic web. I build parameterizations and numerical tools that describe a broad class of dark energy and gravity theories within a unified framework, confront them with data from galaxy surveys and simulations, and study their impact on non‑linear structure formation. I also investigate alternative dark matter models that can simultaneously alleviate several current cosmological tensions.
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MiniSymposium on Modified Gravity
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Naidoo, Jaber, et al (2024), Phys. Rev. D, 109, 083511
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Jaber et al (2022) Physics of the Dark Universe 111069
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C.Ningombam, Mariana Jaber, et al (2020) JCAP 09 (2020) 050
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Jaber et al (2020) Astroparticle Physics 2019 102388
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L. Jaime, M. Jaber et al (2018) Phys Rev D 98 8 083530
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Galaxy - environment connection
My research on the galaxy–environment connection asks how a galaxy’s properties are shaped by its location within the cosmic web and its local density field, from voids to filaments and clusters. Using simulations, I quantify how sizes, stellar masses, star‑formation rates, and metallicities vary with environment.
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Part of our results show that the cosmic web is hierarchical, and that this multiscale web—especially the internal filaments and walls inside large voids—systematically influences how low-mass haloes and galaxies form and evolve. Galaxies in denser parts of the web (walls, filaments, nodes) end up more massive and metal rich with slightly lower spins, while those in voids and the internal “spine-in-voids” network are lighter, more metal poor, and have slightly higher spins, with these environmental effects fading away masses comparable to our own galaxy.​
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Galaxy redshift surveys
During my graduate studies I joined the eBOSS experiment, part of the Sloan Digital Sky Survey (SDSS) collaboration, as a member of the Galaxies and Quasars clustering working group. I developed and applied an Alcock–PaczyÅ„ski (AP) test to the two‑point correlation function of the Luminous Red Galaxies (LRG) sample, comparing clustering along and across the line of sight to infer the geometry of the Universe and test cosmological models via anisotropies in galaxy clustering. This work, which led to my contribution to the eBOSS data‑release paper, gave me direct experience with survey observations and large‑scale data analysis, and strengthened my ability to work within a large, international collaboration.
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R. Ahumada. et al (M Jaber), Astrophys.J.Suppl. 249 (2020) 1, 3
Public code: https://github.com/MarianaJBr/AP-RSD-py​