Bibcode
Quilis, Vicent; Trujillo, I.
Referencia bibliográfica
The Astrophysical Journal Letters, Volume 752, Issue 2, article id. L19 (2012).
Fecha de publicación:
6
2012
Número de citas
21
Número de citas referidas
20
Descripción
Minor merging has been postulated as the most likely evolutionary path
to produce the increase in size and mass observed in the massive
galaxies since z ~ 2. In this Letter, we directly test this hypothesis,
comparing the population of satellites around massive galaxies in
cosmological simulations versus the observations. We use
state-of-the-art, publically available, Millennium I and II simulations,
and the associated semi-analytical galaxy catalogs to explore the time
evolution of the fraction of massive galaxies that have satellites, the
number of satellites per galaxy, the projected distance at which the
satellites locate from the host galaxy, and the mass ratio between the
host galaxies and their satellites. The three virtual galaxy catalogs
considered here overproduce the fraction of galaxies with satellites by
a factor ranging between 1.5 and 6 depending on the epoch, whereas the
mean projected distance and ratio of the satellite mass over host mass
are in closer agreement with data. The larger pull of satellites in the
semi-analytical samples could suggest that the size evolution found in
previous hydrodynamical simulations is an artifact due to the larger
number of infalling satellites compared to the real universe. These
results advise us to revise the physical ingredients implemented in the
semi-analytical models in order to reconcile the observed and computed
fraction of galaxies with satellites, and eventually, it would leave
some room for other mechanisms explaining the galaxy size growth not
related to the minor merging.
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