  The LHCb Collaboration has recently reported strong evidences of the
existence of pentaquark states in the hidden-charm baryon sector, the so-called
$P_c(4380)^+$ and $P_c(4450)^+$ signals. Five-quark bound states in the
hidden-charm sector were explored by us using, for the quark-quark interaction,
a chiral quark model which successfully explains meson and baryon
phenomenology, from the light to the heavy quark sector. We extend herein such
study but to the hidden-bottom pentaquark sector, analyzing possible
bound-states with spin-parity quantum numbers $J^P=\frac12^\pm$, $\frac32^\pm$
and $\frac52^\pm$, and in the $\frac12$ and $\frac32$ isospin sectors. We do
not find positive parity hidden-bottom pentaquark states; however, several
candidates with negative parity are found with dominant baryon-meson structures
$\Sigma_b^{(\ast)}\bar{B}^{(\ast)}$. The calculated distances among any pair of
quarks within the bound-state reflect that molecular-type bound-states are
favored when only color-singlet configurations are considered in the
coupled-channels calculation whereas compact pentaquarks, which are also deeply
bound, can be found when hidden-color configurations are added. Finally, our
findings resemble the ones found in the hidden-charm sector but, as expected,
we find in the hidden-bottom sector larger binding energies and bigger
contributions of the hidden-color configurations.
