Dear Colleague This message is to remind you the conclusions of the HIFI meeting for the ISM core program. As was said on wednesday, we decided to reorganise the ISM prrposal in 4 sections, with coordinators for each section. 1/ ISM structure (F. Boulanger, E. Falgarone) ----------------- The science goals are - Separation of the ISM phases : WIM, WNM, CNM - Determination of the phase physical conditions and characteristics of the small scall sctructure. - putting constraints on the source of ionisation of the ionised medium fine structure lines of C+,N+ and C in the diffuse ISM. Small fields in high latitude clouds and in at different elevations above the Galactic plane will be selected. Pointed observations in the direction of FUSE and HST lines of sight. 2/ Physical and Chemical processes in the Warm and dense ISM (J. Stutzki and V. Ossenkopf) ----------------------------------- The science goals are studying the photochemistry and dynamics of the warm and dense ISM, and provide data to `calibrate' existing models of PDRs, shocks and dense cores. Maps of fine structure lines from N+,C+ and C, and of rotational lines from CO, H2O, C- and N-hydrides. 5 to 10 sources ? 3/ Transition from atomic to molecular gas (E. Falgarone, M. Gerin) ------------------------------------------ The science goals are studying the first steps of interstellar chemistry, particularly the formation of hydrides. Most of the low lying lines of hydrides will be studied in absorption against FIR background sources. Some sources are selected to be strong in the FIR and visible in order to compare observations of the same molecules (CH and CH+) in the Visible and in the submm (using HIFI). 4/ Large molecules (C. Joblin, T. Giesen/J. Stutzki) ------------------ The science goal is to serach for spectral signatures of very large molecule in the ISM. such as carbon chains, PAHs, large radicals, molecules evaporated from ices, etc. For all observations, we must use the new version of the time estimator to derive observing times consistent with the other proposals. The next issue of the proposal is scheduled for 15 march 2003. Juergen Stutzki will provide us directions on how to write the next draft. Juergen and I propose to have a one day meeting in Paris end of April. Could you tell me your preferred dates as soon as possible ? S. Lord is willing to help us with the ISO data base, by answering questions on ISO-LWS data, sources, line fluxes , etc. -------------- Action items : -------------- All : ----- In addition, specific work is needed in the following areas : 1/ Simulation of the expected spectra using HIFI to help us in selecting lines and calculating integration times. We must improve the line selection, particular the choice of water lines most suited to each source. 2/ Provide me an inventory of the available astrophyiscal data which are necessary for planning and interpreting HIFI spectra and maps (ISO, IRAM, KOSMA, HST, etc.) 3/ Needs for preparatory observations, and ideas for future proposals. I include a list of the lines in the core program, with suggestions for future spectrsocopic work. Be careful that the line frequencies have not been checked, so some errors may be remaining. ---------- C. Joblin : Continue the work on PAH spectra to provide a more realistic simulation of the expected signal. F. Boulanger/E. Dartois : Simulation of the signal from a complex organic molecule (produced from the evaporation of ices), and estimation of integration time in one source. J. Stutzki /T. Giesen : Provide the C3 frequencies to include these in the proposal. Plus predictions for the other carbon chains lines. V. Ossenkopf : Selection of shocks and PDR sources for section 2. Ideally, we want to sample with a few sources a range of density, radiation field (strength and hardness). The actual selection includes : Source G0(Habing field) Type of Star Distance(pc) --------------------------------------------- L1721 5 B 120 Octopus(near Zeta Oph) 5 O 120 Rho Oph (W cloud edge) 400 B Horsehead 100 O 450 L1630 10 O 450 Cal. nebula 6 O 300 Ced201 10 B9/A 250 NGC7023 5000 B 450 Orion bar 50000 O 450 IC63 1000 B0 200 --------------------------------------- One SNR shock, IC443 C. Gry : UV and ISO data on the diffuse ISM : Right now we have the following lines of sight : PG0804+761, HD73882, HD34078, HD185418, HD102065 and Zeta Oph. Shall we include HD110231 instead of one of those ? Shall we prefer radio or UV lines of sight in the south, which will be visible with ALMA in the near future ? E. Roueff : H2O excitation in PDR models. Prediction of H2O spectra for a few PDR and shock cases.