Normalized additional velocity distribution: Testing the radial profile of dark matter halos and MOND

Self Cite

We demonstrate how to construct GR-independent equations of state for a neutron star from the information available in the literature. We emphasize the importance of using theory-based principles instead of relying solely on astrophysical observables and General Relativity. We propose a set of equations of state based on first microscopic principles, including chiral perturbation theory and perturbation theory in quantum chromodynamics. Interpolation methods are employed with assumptions on the thermodynamic stability and causality in the intermediate region. These equations of state are then used to constrain quadratic Palatini f(ℛ) gravity, indicating that its free parameter can at most lie within the range around -6.47 ≲ β ≲ 1.99 km2. Additionally, we briefly discuss the problem of phase transitions and twin stars.

Section: Jcap02(2024)017mentioning

confidence: 99%

Constraining Palatini gravity with GR-independent equations of state for neutron stars

Lope-Oter,

Wojnar

2024

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“…In a manner reminiscent of General Relativity, none of the f (R) models effectively account for the rotation curves observed in galaxies [128,129]. Consequently, constraints derived from galaxy catalogs continue to remain elusive up to the present day.…”

Section: Jcap01(2024)011 4 Conclusionmentioning

confidence: 99%

Cosmological constraints of Palatini f(ℛ) gravity

Gomes,

Briffa,

Kozak

et al. 2024

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In this study, we investigate a Palatini f(R) gravity model featuring a quadratic term correction, aligning it with the most recent expansion rate data, with a particular focus on the latest SNIa and BAO data. Our analysis employs CC data as the fundamental dataset, complemented by contributions from the SN sample and a combination of non-overlapping transversal BAO datasets. We conduct a comprehensive MCMC analysis for each data set combination, yielding constraints on all cosmological parameters within the model. Additionally, we incorporate the latest Hubble constant value from the SH0ES Team. Finally, we present a statistical comparison between the Palatini quadratic model and ΛCDM using the AIC and BIC metrics, ultimately obtaining the constraint |α| ≤ 1049 m2. We also stress the significance of studying stellar and substellar objects for obtaining more precise constraints on modified gravity compared to those derived from cosmological observations.

“…In particular, using different fits for the density profiles of galaxies will lead to a different implied virial mass. For example, in other works the Burkert profile was used to fit rotation curves and derive the mass of each galaxy [35,36], changing the results somewhat. The results are plotted in figures 18.…”

Section: Relation Between Soliton Properties and Halo Massmentioning

confidence: 99%

Core and halo properties in multi-field wave dark matter

van Dissel,

Hertzberg,

Shapiro

2024

In this work, we compute multi-field core and halo properties in wave Dark Matter models. We focus on the case where Dark Matter consists of two light (real) scalars, interacting gravitationally. As in the single-field Ultra Light Dark Matter (ULDM) case, the scalar field behaves as a coherent BEC with a definite ground state (at fixed total mass), often referred to in the literature as a gravitational soliton. We establish an efficient algorithm to find the ground and excited states of such two-field systems. We then use simulations to investigate the gravitational collapse and virialization, starting from different initial conditions, into solitons and surrounding halo. As in the single-field case, a virialized halo forms with a gravitational soliton (ground state) at the center. We find some evidence for an empirical relation between the soliton mass and energy and those of the host halo. We use this to then find a numerical relation between the properties of the two. Finally, we use this to address the issue of alleviating some of the tensions that single-field ULDM has with observational data, in particular, the issue of how a galaxy's core and radius are related. We find that if galaxies of different masses have similar percentages of the two species, then the core-radius scaling tension is not addressed. However, more general possibilities occur if the relative abundance of species in each halo correlates with the total mass of the galaxy. If this is the case, the model predicts several other phenomenological signatures.