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dc.contributor.authorFausti Neto, Angelopt_BR
dc.contributor.authorGao, Liangpt_BR
dc.contributor.authorBett, Philippt_BR
dc.contributor.authorCole, Shaunpt_BR
dc.contributor.authorNavarro, Julio F.pt_BR
dc.contributor.authorFrenk, Carlos S.pt_BR
dc.contributor.authorWhite, Simon D. M.pt_BR
dc.contributor.authorSpringel, Volkerpt_BR
dc.contributor.authorJenkins, Adrianpt_BR
dc.date.accessioned2014-04-03T01:51:25Zpt_BR
dc.date.issued2007pt_BR
dc.identifier.issn0035-8711pt_BR
dc.identifier.urihttp://hdl.handle.net/10183/90267pt_BR
dc.description.abstractWe use the Millennium Simulation (MS) to study the statistics of Λ cold dark matter (ΛCDM) halo concentrations at z = 0. Our results confirm that the average halo concentration declines monotonically with mass; the concentration–mass relation is well fitted by a power law over three decades in mass, up to the most massive objects that form in a CDM universe (~ 1015 h-ˡ Mʘ). This is in clear disagreement with the predictions of the model proposed by Bullock et al. for these rare objects, and agrees better with the original predictions of Navarro, Frenk & White. The large volume surveyed, together with the unprecedented numerical resolution of the MS, allows us to estimate with confidence the distribution of concentrations and, consequently, the abundance of systems with unusual properties. About one in a hundred cluster haloes (M200 > ~ 3 × 10 14 h-ˡ Mʘ) have concentrations exceeding c200 = 7.5, a result that may be useful in interpreting the likelihood of unusually strong massive gravitational lenses, such as Abell 1689, in the ΛCDM cosmogony. A similar fraction of about 1 per cent of galaxy-sized haloes (M200 ~ 10 12 h-ˡ Mʘ) have c200 < 4.5 and this could be relevant to models that attempt to reconcile the ΛCDM cosmology with rotation curves of low surface brightness galaxies by appealing to haloes of unexpectedly low concentration. We find that halo concentrations are independent of spin once haloes manifestly out of equilibrium have been removed from the sample. Compared to their relaxed brethren, the concentrations of out-of-equilibrium haloes tend to be lower and have more scatter, while their spins tend to be higher. A number of previously noted trends within the halo population are induced primarily by these properties of unrelaxed systems. Finally, we compare the result of predicting halo concentrations using the mass assembly history of the main progenitor with predictions based on simple arguments regarding the assembly time of all progenitors. The latter are typically as good or better than the former, suggesting that halo concentration depends not only on the evolutionary path of a halo’s main progenitor, but on how and when all of its constituents collapsed to form non-linear objects.en
dc.format.mimetypeapplication/pdf
dc.language.isoengpt_BR
dc.relation.ispartofMonthly notices of the royal astronomical society. Vol. 381, no. 4 (Nov. 2007), p. 1450-1462pt_BR
dc.rightsOpen Accessen
dc.subjectMethods: numericalen
dc.subjectCosmologiapt_BR
dc.subjectMatéria escurapt_BR
dc.subjectGalaxies: haloesen
dc.subjectCosmology: theoryen
dc.subjectMétodos numéricospt_BR
dc.subjectHalospt_BR
dc.subjectDark matteren
dc.titleThe statistics of ΛCDM halo concentrationspt_BR
dc.typeArtigo de periódicopt_BR
dc.identifier.nrb000616897pt_BR
dc.type.originEstrangeiropt_BR


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