Bounds from ISW-galaxy cross-correlations on generalized covariant
  Galileon models
  Several modified cosmological models exist, which also try to address the
tensions between data and predictions of the $\Lambda$-CDM model. Galileon
models are particular scalar tensor theories that represent one such
possibilities. While it is commonly understood that there may be
inconsistencies between predictions of some Galileon models and observations,
in particular concerning ISW-galaxy cross-correlations, there is no proof yet
that these models are completely ruled out. Indeed, by using a specific
background in the generalized covariant Galileon theory known as the the
tracker solution, here we show that, after imposing all standard theoretical
stability constraints, it is still possible to identify a region in the
parameter space of the model that allows for positive ISW-galaxy
cross-correlations. By a physical interpretation in terms of a chi-square
analysis, we confirm the expectation that in this viable region the predictions
of generalized covariant Galileon theory on the tracker solution background
have higher likelihood when they approach the physics of the $\Lambda$-CDM
model.
