For refcode 2010MNRAS.402..395A: Retrieve 30 NED objects in this reference. Please click here for ADS abstract
NED Abstract
Copyright by Royal Astronomical Society.
2010MNRAS.402..395A
Equilibrium configurations of 11 eV sterile neutrinos in MONDian galaxy
clusters
Angus, G. W.; Famaey, B.; Diaferio, A.
Abstract. Modified Newtonian dynamics (MOND) can fit a broad range of
galaxy kinematic data, but struggles with clusters of galaxies. MONDian
clusters need dark matter (DM), and here we test the 11 eVc^2^ sterile
neutrino (SN)  used to fit the first three acoustic peaks of the cosmic
microwave background (CMB)  by investigating their equilibrium
distributions in 30 groups and clusters over a wide range of temperatures.
We do this by first taking the known SN density, necessary for hydrostatic
equilibrium of the intracluster medium (or to produce the observed lensing
map). Then, we solve for the SN velocity dispersion (VD), needed for their
own hydrostatic equilibrium, through the equation of state for a partially
degenerate neutrino gas. The VD is a unique, continuous function of radius
determined by the density and mass of the SN particles. Knowing both the
SN density and VD tells us the TremaineGunn phasespace limit at all
radii. We find that all 30 systems serendipitously reach the TremaineGunn
limit by the centre, which means a portion of the dynamical mass must
always be covered by the brightest cluster galaxy. Interestingly, the
typical fitted Kband masstolight ratio is unity and at most 1.2, which
is very consistent  although leaving no margin for error  with stellar
population synthesis models. Amidst the sample there are several special
cases including the Coma cluster (for which DM was first proposed), NGC
720 (where geometrical evidence for DM was found) and the bullet cluster
(where DM  of some kind  in clusters was directly proven to exist). We
demonstrate that 11 eVc^2^ SNs are unlikely to influence spiral galaxy
rotation curves, as they do not influence even some very massive
earlytypes (NGC 4125 and NGC 6482). Finally, we conclude that it is
intriguing that the minimum mass of SN particle that can match the CMB is
the same as the minimum mass found here to be consistent with equilibrium
configurations of MONDian clusters of galaxies.
Key words: neutrinos, dark matter, Xrays: galaxies: clusters
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