Implications of the correlation between bulge-to-total baryonic mass
  ratio and the number of satellites for SAGA galaxies
  We searched for correlations between the number of satellites and fundamental
galactic properties for the Milky Way-like host galaxies in order to better
understand their diverse satellite populations. We specifically aim to
understand why galaxies that are very similar in stellar mass content, star
formation rate, and local environment have very different numbers of
satellites. Satellites of Galactic Analogs (SAGA) spectroscopic survey has
completed spectroscopic observations of 36 Milky Way-like galaxies within their
virial radii down to the luminosity of Leo I dwarf galaxy. All the available
galactic properties of SAGA galaxies from the literature along with measured
stellar masses were correlated with the number of satellites and no significant
correlation was found. However, when we considered the "expected" number of
satellites based on the correlation between the baryonic bulge-to-total ratio
and the number of satellites confirmed for several nearby galaxies then strong
correlations emerge between this number and (1) the mass of the bulge, and (2)
the total specific angular momentum. The first correlation is positive,
implying that galaxies with more massive bulges have more satellites, as
already confirmed. The second correlation with the angular momentum is
negative, meaning that, the smaller the angular momentum, the greater the
number of expected satellites. This would imply that either satellites cannot
form if galaxy angular momentum is too high, or that satellites form
inside-out, so that angular momentum is being transferred to the outer parts of
the galaxies. However, deeper spectroscopic observations are needed to confirm
these findings, because they rely on the expected rather than detected number
of satellites. There was a luminosity limit to the SAGA survey equivalent to
the luminosity of Leo I dwarf satellite of the Milky Way galaxy.
