  Cold molecular gas has been recently detected in several cooling flow
clusters of galaxies where huge optical nebulosities often stand. These optical
filaments are tightly linked to the cooling flow and to the related phenomena,
like the rising bubbles of relativistic plasma, fed by the radio jets. We
present here a map in the CO(2-1) rotational line of the cold molecular gas
associated with some Halpha filaments surrounding the central galaxy of the
Perseus cluster: NGC 1275. The map, extending to about 50 kpc (135 arcsec) from
the center of the galaxy, has been made with the 18-receiver array HERA, at the
focus of the IRAM 30m telescope. Although most of the cold gas is concentrated
to the center of the galaxy, the CO emission is also clearly associated to the
extended filaments conspicuous in ionised gas and could trace a possible
reservoir fueling the star formation there. Some of the CO emission is also
found where the X-ray gas could cool down more efficiently: at the rims of the
central X-ray cavity (where the hot gas is thought to have been pushed out and
compressed by the central AGN expanding radio lobes). The CO global kinematics
does not show any rotation in NGC 1275. The cold gas is probably a mixture of
gas falling down on the central galaxy and of uplifted gas dragged out by a
rising bubble in the intracluster medium. As recenlty suggested in other
cluster cores, the cold gas peculiar morphology and kinematics argue for the
picture of an intermittent cooling flow scenario where the central AGN plays an
important role.
