TY - JOUR
T1 - Constraining warm dark matter using QSO gravitational lensing
AU - Miranda, Marco
AU - MacCiò, Andrea V.
N1 - Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 2007/12
Y1 - 2007/12
N2 - Warm dark matter (WDM) has been invoked to resolve apparent conflicts of cold dark matter (CDM) models with observations on subgalactic scales. In this work, we provide a new and independent lower limit for the WDM particle mass (e.g. sterile neutrino) through the analysis of image fluxes in gravitationally lensed quasi-stellar objects (QSOs). Starting from a theoretical unperturbed cusp configuration, we analyse the effects of intergalactic haloes in modifying the fluxes of QSO multiple images, giving rise to the so-called anomalous flux ratio. We found that the global effect of such haloes strongly depends on their mass/abundance ratio and it is maximized for haloes in the mass range 10 6-108 M⊙. This result opens up a new possibility to constrain CDM predictions on small scales and test different warm candidates, since free streaming of WDM particles can considerably dampen the matter power spectrum in this mass range. As a consequence, while a (Λ)CDM model is able to produce flux anomalies at a level similar to those observed, a WDM model, with an insufficiently massive particle, fails to reproduce the observational evidences. Our analysis suggests a lower limit of a few keV (mν ∼ 10) for the mass of WDM candidates in the form of a sterile neutrino. This result makes sterile neutrino WDM less attractive as an alternative to CDM, in good agreement with previous findings from Lyman α forest and cosmic microwave background analysis.
AB - Warm dark matter (WDM) has been invoked to resolve apparent conflicts of cold dark matter (CDM) models with observations on subgalactic scales. In this work, we provide a new and independent lower limit for the WDM particle mass (e.g. sterile neutrino) through the analysis of image fluxes in gravitationally lensed quasi-stellar objects (QSOs). Starting from a theoretical unperturbed cusp configuration, we analyse the effects of intergalactic haloes in modifying the fluxes of QSO multiple images, giving rise to the so-called anomalous flux ratio. We found that the global effect of such haloes strongly depends on their mass/abundance ratio and it is maximized for haloes in the mass range 10 6-108 M⊙. This result opens up a new possibility to constrain CDM predictions on small scales and test different warm candidates, since free streaming of WDM particles can considerably dampen the matter power spectrum in this mass range. As a consequence, while a (Λ)CDM model is able to produce flux anomalies at a level similar to those observed, a WDM model, with an insufficiently massive particle, fails to reproduce the observational evidences. Our analysis suggests a lower limit of a few keV (mν ∼ 10) for the mass of WDM candidates in the form of a sterile neutrino. This result makes sterile neutrino WDM less attractive as an alternative to CDM, in good agreement with previous findings from Lyman α forest and cosmic microwave background analysis.
KW - Cosmology: theory
KW - Dark matter
KW - Galaxies: haloes
KW - Gravitational lensing
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U2 - 10.1111/j.1365-2966.2007.12440.x
DO - 10.1111/j.1365-2966.2007.12440.x
M3 - Article
AN - SCOPUS:36549030233
VL - 382
SP - 1225
EP - 1232
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 3
ER -