Bibcode
López-Corredoira, M.; Gutiérrez, C. M.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 461, Issue 1, January I 2007, pp.59-69
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1
2007
Revista
Número de citas
10
Número de citas referidas
1
Descripción
Aims:To check whether the polar angle distribution of QSOs around nearby
spiral galaxies is isotropic or not. Methods: A statistical
analysis of the polar angle distribution of large samples of QSOs from
the SDSS survey and Monte Carlo simulations to calculate their
significance are carried out. Results: There is a clear excess of
QSOs near the minor axis with respect to the major axis of nearby
edge-on spiral galaxies, significant at a level 3.5σ up to angular
distances of ~ 3° (or ˜ 1.7 Mpc) from the centre of each
galaxy. The significance is increased to 3.9σ with the z>0.5
QSOs, and it reaches 4.8σ if we include galaxies whose circles of
radius 3 degrees are covered by the SDSS in more than 98% (instead of
100%) of the area. Conclusions: .Gravitational lensing in the halo
of nearby galaxies or extinction seem insufficient to explain the
observed anisotropic distribution of QSOs. The anisotropic distribution
agrees qualitatively with the predictions of Arp's models, which claim
that QSOs are ejected by galaxies along the rotation axis, although
Arp's prediction give a distance of the QSOs ˜ 3 times smaller
than that found here. In any case, a chance fluctuation, although highly
improbable, might be a possibility rather than a true anisotropy, and
the present results should be corroborated by other groups and samples,
so we prefer to consider it as just a first tentative detection.