  We present a 3-dimensional study of the local ($\leq 100 h^{-1}$ kpc) and the
large scale ($\leq$ 1 $h^{-1}$ Mpc) environment of Bright IRAS Galaxies
(BIRGs). For this purpose we use 87 BIRGs located at high galactic latitudes
(with 0.008$\leq z \leq$0.018) as well as a control sample of non-active
galaxies having the same morphological, redshift and diameter size
distributions as the corresponding BIRG sample. Using the Center for
Astrophysics (CfA2) and Southern Sky Redshift Survey (SSRS) galaxy catalogues
($m_b\lesssim 15.5$)as well as our own spectroscopic observations
($m_b\lesssim19.0$) for a subsample of the original BIRG sample, we find that
the fraction of BIRGs with a close neighbor is significantly higher than that
of their control sample. Comparing with a related analysis of Sy1 and Sy2
galaxies of Koulouridis et al. (2006) we find that BIRGs have a similar
environment as Sy2s, although the fraction of BIRGs with a bright close
neighbor is even higher than that of Sy2 galaxies. An additional analysis of
the relation between FIR colors and the type of activity of each BIRG shows a
significant difference between the colors of strongly-interacting and
non-interacting starbursts and a resemblance between the colors of
non-interacting starbursts and Sy2s. Our results support the view where close
interactions can drive molecular clouds towards the galactic center, triggering
starburst activity and obscuring the nuclear activity. When the close neighbor
moves away, starburst activity is reduced with the simultaneous appearance of
an obscured (type 2) AGN. Finally, the complete disentanglement of the pair
gives birth to an unobscured (type 1) AGN.
