CO(1-0) OBSERVATIONS OF THE COOLING FLOW GALAXY NGC-1275 WITH THE IRAM INTERFEROMETER

High resolution (CO)-C-12 (1-0) interferometric observations are prese nted of NGC 1275 (3C84, Perseus A), which is the dominant galaxy of th e Perseus cluster (Abell 426) and is believed to have a strong cooling flow. No CO absorption was detected towards the powerful point-like n ucleus although CO emission may have been detected in an area surround ing the nucleus. The constraints placed by these observations and exis ting data on the massive cooling flow scenario are examined. Contrary to some claims, the covering fraction of neutral gas has been found to be much less than unity in all cooling flows where the necessary data are available. As the cooling gas presumably forms low-mass stars or sub-stellar objects, the possibility of large masses of neutral gas es caping detection is investigated in detail. The gas, with or without d ust, should not cool down to T-gas approximate to 3 K as has been clai med but should remain greater than or similar to 8 K through X-ray hea ting at column densities up to N-H2 approximate to 5 10(22) cm(-2). Gr eater column densities may be physically reasonable if the magnetic fi eld is strong enough to support the cloud against fragmentation. In th is case, ambi-polar diffusion or magnetic slip-ion heating becomes imp ortant and should maintain the temperature T-gas greater than or simil ar to 10 K. If the clouds contain dust, then although the dust radiate s away most of the energy, the absorbed starlight keeps the temperatur e T-dust greater than or similar to 10 K. Lack of CO or very broad lin es do not appear to be feasible means of reconciling large molecular ( or atomic) gas masses with the global lack of detections and tight upp er limits. The primary conclusion is that the real mass inflow rates m ust be much lower that frequently claimed. It should then be noted tha t present-day cooling flows, if not so massive, lose much of their cos mological importance. The FIR and CO emission from NGC 1275 correspond exactly to what is found in gas-rich spirals. Rather than a massive c ooling flow, the gas may come from accretion of one or more gas-rich g alaxies. Since, however, at least 14 other central galaxies would have been detected in CO if they contained similar quantities of gas, such events must be quite rare, very roughly 1/15 Gyr(-1) if the time requ ired for a large fraction of the gas to disappear is 10(9) yr.