Abstract:
Recent studies with SDSS have shown that a statistically significant non-zero mu tual information between morphology and environment persists up to several tens of Mpc,
which awaits an explanation. Galaxies in different environments acquire their stellar mass
through accretion and merger and the stellar mass function of galaxies is known to depend on
both environment and morphology. Naturally, stellar mass can be an important link between
morphology and environment which may explain the non-zero mutual information between
the two. Measuring the mutual information between morphology and environment by condi tioning the stellar mass would allow us to test this possibility. We employ here a volume and
stellar mass limited sample from the 16th data release (DR16) of the SDSS and find a non-zero
conditional mutual information throughout the entire length scales probed. We compare the
results with three different semi-analytic models implemented on the Millennium simulation
and find their predictions to be in fairly good agreement with SDSS on smaller length scales
(. 30 h
−1 Mpc), with a clear discrepancy observed at larger length scales (& 30 h
−1 Mpc)
where the models predict significantly lower conditional mutual information than the SDSS.
Our analysis therefore suggests that only environmental and morphology dependence of stel lar mass are inadequate in explaining the observed mutual information between morphology
and environment and that physical processes which alters morphology may not necessarily
have an impact on the stellar mass of galaxies and vice versa.
