<=== observer ===> "HSMITH",\ "Smith, Howard A.",\ "Laboratory for Astrophysics",\ "National Air and Space Museum",\ "Smithsonian Institution",\ "",\ "",\ "Washington DC 20560",\ "United States",\ "202 357 4932",\ "202 633 8174",\ "howard@wright.nasm.edu" <=== proposal ===> "COOLFLOW",1,4,\ {"cooling flows", "galaxy clusters", "active galactic nuclei"},\ {"LWS consortium", "Fischer", "Greenhouse", "Stacey", "Spinoglio"} <=== title ===> ISO Spectroscopy of the Cooling Flow Cluster Central Galaxy NGC 1275 <=== abstract ===> SCIENTIFIC ABSTRACT X-ray observations have shown that hot (1 x 10(8) K) gas, thought to arise from primordial gas, surrounds clusters of galaxies. The cooling time of this low density gas is thought to be longer than the age of the universe. However, the cooling time of the denser gas near the central cluster galaxy is much shorter. In the cooling flow centered on the central galaxy of the nearby Persius cluster, NGC 1275, the mass inflow rate has been estimated to be about 200 Mo/yr. These mass inflow rates are significantly higher than derived quasar accretion rates or star formation rates derived from optical studies. Furthermore, the gas is not present in the form of HI or cold molecular gas. The nature of the gas in cooling flows and its ultimate fate, will be probed in a detailed study of the cooling flow in the central galaxy of the nearby Persius cluster, NGC 1275. By observing in the medium and high-J rotational lines of CO, and the fine structure lines from a full ISO/LWS scan, we plan to derive better constraints on the conditions and abundances in warm gas than have been provided to date, and to study the effects of the flow on the galactic IMF and interstellar medium. OBSERVATION SUMMARY At present, estimates of the star formation rate in NGC 1275 have been obtained from optical studies. The fine structure lines in the LWS range will be used to derive the physical conditions of the neutral interstellar medium and in particular will allow determination of the past and present rates of star formation, unbiased by dust extinction. The [CII] 158 um, and [OI] 63 um and 145 um line intensities when combined with knowledge of the FIR continuum and CO line intensities, may be used to determine the gas density, temperature, and mass of the atomic gas in photodissocation regions. Intensity measurements of the [OIII], [NIII], [NII] lines then allow determination of the N/O abundance ratio, which helps place constraints on the amounts of past nuclear processing. X-ray and shock heated warm molecular gas may also be present, and may be observed in rotational lines of CO, H20, and OH. Observation of these lines will be important to constrain the excitation and mass of the accreting gas. We will obtain a full LWS grating scan of NGC 1275. The on-source integration time was chosen to yield a S/N ratio of about 10 on the weakest expected fine structure lines, such as [NII] 121.9 and [NIII] 57.3. A 4 point map around the central position will provide for subtraction of possible cirrus contamination features, and will also provide some information on the radial dependence of detected features. Follow up time for Fabry-Perot velocity resolved observations of any very strong diagnostic lines will be taken from priority 3 program sources in other parts of the LWS Consortium Extragalactic program. Additional details can be found in the LWS Schloss Elmau Meeting Document: "ISO: LWS Guaranteed Time Proposals", LWS/90/P/SCI/135.00, November 1990. <=== scientific_justification ===> Time distribution for Autumn launch: Team top 40% second 30% last 30% LWS: 0 0 0 total: 0 0 0 Time distribution for Spring launch: Team top 40% second 30% last 30% LWS: 0 25452 0 total: 0 25452 0 <=== autumn_launch_targets ===> <=== spring_launch_targets ===> 01, "LWS01", 2., "N", "NGC 1275 ", 03.27447, +41.32972, 1950,0., 0.,12764,2 02, "LWS01", 2., "N", "NGC 1275-N ", 03.27447, +41.39639, 1950,0., 0., 3172,3 03, "LWS01", 2., "N", "NGC 1275-S ", 03.27447, +41.26305, 1950,0., 0., 3172,4 04, "LWS01", 2., "N", "NGC 1275-E ", 03.28039, +41.32972, 1950,0., 0., 3172,5 05, "LWS01", 2., "N", "NGC 1275-W ", 03.26855, +41.32972, 1950,0., 0., 3172,0