The Evolution of Galaxies on Cosmological Timescales

Beckman, J. E.; Mahoney, T. J.
Referencia bibliográfica

The Publications of the Astronomical Society of the Pacific, Volume 111, Issue 758, pp. 523-523.

Fecha de publicación:
4
1999
Número de autores
2
Número de autores del IAC
0
Número de citas
0
Número de citas referidas
0
Descripción
The Euroconference “The Evolution of Galaxies on Cosmological Timescales” was held in Puerto de la Cruz, Tenerife, Spain between 1998 November 30 and December 5. It brought together two communities of astronomers who normally do not talk sufficiently together: those studying the detailed evolution of nearby galaxies, and those studying the properties of galaxies and clusters at high redshift. The first 2 days were dedicated to the structure, chemistry, dynamics, and evolution of the Galaxy and of nearby galaxies, with conscious reference at many points to the potential implications for the study of more distant galaxies. The meeting then moved to the global themes of the synthesis of stellar populations, the history of the star formation rate, and the characterization of the initial mass function, again linking explicitly detailed local studies with new observations at high z. Then passing through the topic of mergers, as a key element in galaxy evolution, the subject moved to focus on studies of the Hubble Deep Field (and the promise of its southern counterpart, announced a week before the conference), of spectroscopic studies with the largest telescopes (notably the Keck), and finished with a brief look at the epoch of galaxy formation. The proceedings of this conference will contain the major contributions to the conference, including the invited talks that had review or semireview character and the larger contributions of a monographic nature. Some of the most striking points brought out at the conference include the following: 1. The possibility that in groups of galaxies, such as our Local Group, a significant fraction of the neutral gas is in the form of rather massive clouds that are gravitationally bound within the group and that are accreting at a steady average rate onto large galaxies over a Hubble time. This scenario, which appears to be supported by the properties of the high‐velocity clouds detected falling toward the Galaxy, fits into a global picture of the development of galaxies by mergers and accretions rather than during a very sharply peaked epoch of galaxy formation. It also has many implications for chemical evolution. 2. The probability that a significant fraction of the ionizing photons emitted within a normal spiral or irregular galaxy escapes into the intergalactic medium and is responsible for its ionization (yet another way of hiding baryons from immediate detection). 3. The fact that dust, both within galaxies and in the intergalactic medium, can effectively block the direct detection at visible and near‐IR wavelengths of much of the radiation that may well come from galaxies at . This effect most probably implies that the fairly recently postulated peak of star‐forming activity in galaxies at a redshift close to could be an artifact owing to this effect (the cosmological equivalent of the Kapteyn vision of the Milky Way at the beginning of the century, which turned out to be a dust‐blinded view) and that the epoch of strong galaxy formation extended to considerably higher z. 4. The invention of new techniques in stellar population synthesis that promise to break the age‐metallicity degeneracy and give us more reliable estimates of the ages and, indeed, of the metallicities of galaxies over long timescales. The fact that astrophysicists of 11 nationalities working in eight different countries have contributed to the 25 papers of the present proceedings gave a special touch that characterized this Euroconference. While the biggest single contingent of authors came from the United States, there were researchers from Europe, South America, and Japan represented here. In the meeting as a whole, over 25 nationalities were present. The conference was held in the Canary Islands, one of the world’s centers for observational astrophysics, but also, like Hawaii, islands with much to offer in climate to allow a winter meeting such as this one to take place in the most agreeable surroundings for intellectual exchange. The quality as well as the variety of the contributions to the conference and forthcoming proceedings reflects these attractions of the venue.