Spherical collapse in generalized dark matter models

Pace, Francesco; Sakr, Z.; Tutusaus, I.

doi:10.1103/physrevd.102.043512

Cited by 13 publications

(8 citation statements)

References 57 publications

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“…However, our set-up is more general than that and the correct way of proceeding needs to take into account the additional degrees of freedom of our model. In this respect, our physical set-up is very similar to what has been recently done for generalised DM [39,40] by [41]. One of the differences with respect to that work is that in our case both the background EoS and the sound speed are, in general, time-dependent and need both to be properly evaluated.…”

Section: Evolution Of the Growth Factormentioning

confidence: 93%

Testing generalized logotropic models with cosmic growth

Boshkayev,

Konysbayev,

Luongo

et al. 2021

Preprint

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We check the dynamical and observational features of four typologies of logotropic dark energy models, leading to a thermodynamic cosmic speed up fueled by a single fluid that unifies dark energy and dark matter. We first present two principal Anton-Schmidt fluids where the Grüneisen parameter γG is free to vary and then fixed to the special value γG = 5 6 . We also investigate the pure logotropic model, corresponding to γG = − 1 6 . Finally, we propose a new logotropic paradigm that works as a generalized logotropic fluid, in which we split the role of dark matter and baryons. We demonstrate that the logotropic paradigms may present drawbacks in perturbations, showing a negative adiabatic sound speed which make perturbations unstable. We thus underline which model is favored over the rest. The Anton-Schmidt model with γG = 5 6 is ruled out while the generalized logotropic fluid seems to be the most suitable one, albeit weakly disfavored than the ΛCDM model. To fix numerical constraints, we combine low-and higher-redshift domains through experimental fits based on Monte Carlo Markov Chain procedures, taking into account the most recent Pantheon supernovae Ia catalogue, Hubble measurements and σ8 data points based on the linear growth function for the large scale structures. We also consider two model selection criteria to infer the statistical significance of the four models under exam. We conclude there is statistical advantage to handle the Anton-Schmidt fluid with the Grüneisen parameter free to vary and/or fixed to γG = − 1 6 . The generalized logotropic fluid indicates suitable results, statistically favored than the other models, until the sound speed is positive, becoming unstable in perturbations elsewhere. We emphasize that the ΛCDM paradigm works statistically better than any kinds of logotropic and generalized logotropic models, while the Chevallier-Polarski-Linder parametrization is statistically comparable with logotropic scenarios. Finally, we propose that generalizing the Grüneisen parameter by including the effects of temperature would guarantee the sound speed to be positive definite at all redshifts.

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Section: Evolution Of the Growth Factormentioning

confidence: 93%

Testing generalized logotropic models with cosmic growth

Boshkayev,

Konysbayev,

Luongo

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…However, our setup is more general than that and the correct way of proceeding needs to take into account the additional degrees of freedom of our model. In this respect, our physical setup is very similar to what has been recently done for generalized DM [39,40] by [41]. One of the differences with respect to that work is that in our case both the background EoS and the sound speed are, in general, time dependent and both need to be properly evaluated.…”

Section: Evolution Of the Growth Factormentioning

confidence: 95%

Testing generalized logotropic models with cosmic growth

et al. 2021

Self Cite

View full text Add to dashboard Cite

We check the dynamical and observational features of four typologies of logotropic dark energy models, leading to a thermodynamic cosmic speed up fueled by a single fluid that unifies dark energy and dark matter. We first present two principal Anton-Schmidt fluids where the Grüneisen parameter γ G is free to vary and then fixed to the special value γ G ¼ 5 6 . We also investigate the pure logotropic model, corresponding to γ G ¼ − 1 6 . Finally, we propose a new logotropic paradigm that works as a generalized logotropic fluid, in which we split the role of dark matter and baryons. We demonstrate that the logotropic paradigms may present drawbacks in perturbations, showing a negative adiabatic sound speed which make perturbations unstable. We thus underline which model is favored over the rest. The Anton-Schmidt model with γ G ¼ 5 6 is ruled out while the generalized logotropic fluid seems to be the most suitable one, albeit weakly disfavored than the ΛCDM model. To fix numerical constraints, we combine low-and higher-redshift domains through experimental fits based on Monte Carlo Markov Chain procedures, taking into account the most recent Pantheon supernovae Ia catalog, Hubble measurements, and σ 8 data points based on the linear growth function for the large scale structures. We also consider two model selection criteria to infer the statistical significance of the four models under examination. We conclude there is a statistical advantage to handle the Anton-Schmidt fluid with the Grüneisen parameter free to vary and/or fixed to γ G ¼ − 1 6 . The generalized logotropic fluid indicates suitable results, more statistically favored than the other models until the sound speed is positive, becoming unstable in perturbations elsewhere. We emphasize that the ΛCDM paradigm works statistically better than any kind of logotropic and generalized logotropic models, while the Chevallier-Polarski-Linder parametrization is statistically comparable with logotropic scenarios. Finally, we propose that generalizing the Grüneisen parameter by including the effects of temperature would guarantee the sound speed to be positive definite at all redshifts.

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“…The standard cosmological framework Lambda Cold Dark Matter (ΛCDM) [1] has proven to be extremely successful in explaining the formation and evolution of large scale structures in our Universe [2][3][4]. However, at the galactic scales there exists several mismatch between simulation and observations [5].…”

Section: Introductionmentioning

confidence: 99%

Constraints on dark matter self-interaction from galactic core size

Ray¹,

Sarkar²,

Shaw³

2022

Preprint

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Self interaction of particulate dark matter may help thermalising the galactic center and driving core formation. The core radius is expectantly sensitive to the self interaction strength of dark matter. In this paper we study the feasibility of constraining dark matter self interaction from the distribution of the core radius in isolated haloes. We perform systematic N -body simulations of isolated galactic haloes in the mass range of 10 10 -10 15 M incorporating the impact of DM self interactions. Comparing the simulated profiles with observational data provides conservative upper limit on the self coupling cross-section σ/m DM < 9.8 cm 2 /gm at 95% confidence level. We report significant dependence of the derived bounds on the galactic density distribution models assumed in the analysis.

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Spherical collapse in generalized dark matter models

Cited by 13 publications

References 57 publications

Testing generalized logotropic models with cosmic growth

Testing generalized logotropic models with cosmic growth

Testing generalized logotropic models with cosmic growth

Constraints on dark matter self-interaction from galactic core size

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