Dark Matter in the Halo of the Galaxy

Bilić, Neven; Tupper, Gary B.; Viollier, Raoul D.

doi:10.1007/978-3-642-55739-2_16

Cited by 79 publications

(103 citation statements)

References 33 publications

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“…However, we maintain, contrary to the opinion advocated in [21], that the sound speed problem may be alleviated in unified models no more unnatural than the ΛCDM model. Indeed, an encouraging feature of the positive power-law potential is that it provides for acceleration as a periodic transient phenomenon [63] which obviates the de Sitter horizon problem [41] , and, we speculate, could even be linked to inflation.…”

Section: Discussionmentioning

confidence: 83%

Cosmological tachyon condensation

2009

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We consider the prospects for dark matter/energy unification in k-essence type cosmologies. General mappings are established between the k-essence scalar field, the hydrodynamic and braneworld descriptions. We develop an extension of the general relativistic dust model that incorporates the effects of both pressure and the associated acoustic horizon. Applying this to a tachyon model, we show that this inhomogeneous "variable Chaplygin gas" does evolve into a mixed system containing cold dark matter like gravitational condensate in significant quantities. Our methods can be applied to any dark energy model, as well as to mixtures of dark energy and traditional dark matter.

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Section: Discussionmentioning

confidence: 83%

Cosmological tachyon condensation

2009

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“…only the fluctuations of the CDM component are responsible for large scale structure, we can write ρ M =ρ M (1 + δ), ρ G =ρ G . Expanding according to (10) we find that…”

Section: Gravitational Collapsementioning

confidence: 99%

Large scale structure and the generalized Chaplygin gas as dark energy

2004

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The growth of large scale structure is studied in a universe containing both cold dark matter (CDM) and generalized Chaplygin gas (GCg). GCg is assumed to contribute only to the background evolution of the universe while the CDM component collapses and forms structures. We present some new analytical as well as numerical results for linear and non-linear growth in such model. The model passes the standard cosmological distance test without the need of a cosmological constant (LCDM). But we find that the scenario is severely constrained by current observations of large scale structure. Any small deviations of the GCg parameters away from the standard Lambda dominated cosmology (LCDM) produces substantial suppression for the growth of structures.

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“…The Chaplygin gas model has been generalized by considering that the pressure, besides to be negative, depends on an arbitrary power of the inverse of the density. One of the great advantages of the Generalized Chaplygin gas model (GCGM) is the possibility of unifying the description of dark energy and dark matter [14,15]: a fraction of this exotic fluid can agglomerate locally, while the other fraction remains a smooth component. However, criticisms have been addressed to this proposal mainly due to its behaviour concerning density perturbations, which exhibits large oscillations in the resulting power spectrum which do not appear in the observed power spectrum of mass agglomeration [16].…”

Section: Introductionmentioning

confidence: 99%

Bulk viscosity driving the acceleration of the Universe

2006

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The possibility that the present acceleration of the universe is driven by a kind of viscous fluid is exploited. At background level this model is similar to the generalized Chaplygin gas model (GCGM). But, at perturbative level, the viscous fluid exhibits interesting properties. In particular the oscillations in the power spectrum that plagues the GCGM are not present. Possible fundamental descriptions for this viscous dark energy are discussed. PACS number(s): 04

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Dark Matter in the Halo of the Galaxy

Cited by 79 publications

References 33 publications

Cosmological tachyon condensation

Cosmological tachyon condensation

Large scale structure and the generalized Chaplygin gas as dark energy

Bulk viscosity driving the acceleration of the Universe

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