XXIVth IAU GENERAL ASSEMBLY (MANCHESTER, AUG. 7-18, 2000) JOINT DISCUSSION (JD 1) Atomic and molecular data for astrophysics: new developments, case studies and future needs Aug. 9-11, 2000

    The reduction, analysis, interpretation and modelling of the observational results requires at each stage more and more extensive sets of laboratory data especially since the objects studied are often in extreme physical conditions which cannot be reproduced in the laboratory and can be studied only by modelling. Since the early days of astrophysics, when the needs concerned essentially atomic spectra in the visible range, the requests have extended to the whole range of wavelengths from gamma rays to radio waves. Even within the specific realm of Atomic and Molecular Physics, which is essentially that of Commission 14, the extension of the subject matter has been impressive: Spectra of isolated ions, molecular radicals, small and large molecules, and of amorphous and crystalline solids are now needed, often at very high spectral resolutions. Process rates are also needed in order to model a very wide range of astronomical objects in widely varying physical conditions : gas phase and surface reaction rates; photorates, for excitation, ionization, dissociation of gas phase and solid state species, just to name the most obvious ones.

    In the past, a large part of the data needed has been spontaneously provided by the Atomic and Molecular Physics community in the course of its own development. However, more and more specific needs are appearing in connection with space and ground based instruments. Analysis of the data obtained from the very expensive new facilities is sometimes limited by the accuracy and availability of the necessary Atomic an Molecular data. These specific needs have to be covered through concerted efforts and at least partially funded by the Astronomy and Space budgets. In this respect, it is the function of Commission 14, first to help keep the astronomers informed of the available data and of the programs undertaken in other communities, second, to favour the exchange of information in order to make the Atomic and Molecular Physics community aware of the needs of Astronomy for new data and, finally, to help make the program agencies aware of the needs for specific studies and funding in these areas.

    It seems quite appropriate at this time, in view of the rapid evolution in the scope and quality of astronomical observations and models, to assess the present and forseeable needs of Astronomy for new data and the possibility to obtain them. To this end, Commission 14 organizes a Joint Discussion at the next General Assembly where recently available and needed data will be reviewed for a few selected fields centered around space missions and ground based facilities, specific objects or specific processes.

    The program is organized around topics chosen either because they correspond to future or very recent space missions or because they are fast moving and are particularly in need of new laboratory data. In addition, case studies will be presented in which a particular species or process is studied from several angles, thus contributing effectively to the interpretation of astronomical observations or models.

    Poster contributions are heartily encouraged in order to complement the invited oral presentations.