Génova-Santos, R.; Padilla-Torres, C. P.; Rubiño-Martín, J. A.; Gutiérrez, C. M.; Rebolo, R.
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 403, Issue 3, pp. 1531-1540.
Fecha de publicación:
4
2010
Número de citas
4
Número de citas referidas
4
Descripción
We present a study of the spatial and redshift distributions of Sloan
Digital Sky Survey (SDSS) galaxies towards the position of CrB-H, a very
deep and extended decrement in the cosmic microwave background (CMB),
located within the Corona Borealis supercluster (CrB-SC). It was found
in a survey with the Very Small Array (VSA) interferometer at 33 GHz,
with a peak negative brightness temperature of -230μK, and deviates
4.4σ from the Gaussian CMB (Génova-Santos et al.).
Observations with the Millimeter and Infrared Testa Grigia Observatory
(MITO) suggested that 25+21-18 per cent of this
decrement may be caused by the thermal Sunyaev-Zel'dovich (tSZ) effect
(Battistelli et al.). Here, we investigate whether the galaxy
distribution could be tracing either a previously unnoticed galaxy
cluster or a warm/hot intergalactic medium (WHIM) filament that could
build up this tSZ effect. We find that the projected density of galaxies
outside Abell clusters and with redshifts 0.05 < z < 0.12 at the
position of CrB-H is the highest in the area encompassed by the CrB-SC.
Most of these galaxies are located around redshifts z = 0.07 and 0.11,
but no clear connection in the form of a filamentary structure is
appreciable in between. While the galaxy distribution at z = 0.07 is
sparse, we find evidence at z = 0.11 of a galaxy group or a low-mass
galaxy cluster. We estimate that this structure could produce a thermal
Sunyaev-Zel'dovich (tSZ) effect of ~ -18μK. The remaining VSA signal
of ~ -212μK is still a significant 4.1σ deviation from the
Gaussian CMB. However, the MITO error bar allows for a larger tSZ
effect, which could be produced by galaxy clusters or superclusters
beyond the sensitivity of the SDSS. Contributions from other possible
secondary anisotropies associated with these structures are also
discussed.
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