This abstract not available.
[H3.002] A Chandra and XMM View of the Metals in Groups and Clusters of Galaxies
David Buote (University of California, Irvine)
I review measurements of the metal abundances in the hot gas
of groups and clusters of galaxies obtained from recent
X-ray observations with the Chandra and XMM satellites.
Initial studies of the iron and silicon abundances in
centrally E-dominated groups show that they have pronounced
gradients from 1-2 solar values within the central 30-50 kpc
that fall to values of 0.3-0.5 solar at larger radii. The
Si/Fe ratios are consistent with approximately 80% of the
metals originating from Type Ia supernovae. Several cD
clusters also display central Fe enhancements suggestive of
Type Ia supernova enrichment, though some have central dips
that may provide a vital clue for solving the cooling flow
mystery.
[H3.003] Hot X-ray emitting gas in galaxies
G. Fabbiano (Harvard University)
Hot X-ray emitting gas was discovered in galaxies with the Einstein Observatory, 25 year ago. This hot Interstellar Medium (ISM) may be in thermal equilibrium with the stars in large galaxy bulges (e.g. elliptical and lenticular galaxies) or may be heated by supernovae (SNIa). In star-forming
galaxies (spirals, irregulars, merging galaxies) the ISM may be heated by star formation activity, via stellar winds and most efficiently supernova explosions. In this talk I will address recent Chandra observations of hot ISM in star-forming galaxies. X-ray observations of nearby galaxies, in combination with data from other regions of the electromagnetic spectrum, have revealed a complex multi-phase ISM in active star forming regions. Hot super-winds are seen escaping star-burst nuclei, undoubtly carrying with them elements into the intergalactic space. The study of these galaxies may give us a direct (albeit down-scaled) view of galaxy formation in act.
[H3.004] Galactic Fountains and Winds --- the link between galaxies and the intergalactic medium
David Strickland (The Johns Hopkins University)
This abstract not available.
[H3.005] Molecular Gas and Star Formation in Nearby Galaxies
Michele D. Thornley (Bucknell University)
>From studies of the Milky Way, we know that molecular gas is intrinsically tied to the process of forming stars. However, to appreciate fully the role that star formation plays in galaxy evolution, we want to assess the connection between star formation and larger-scale structure in galaxies. This is more straightforward in external galaxies, where we are free of the inherent difficulties of observing from within the structure we are studying. In addition, studies of molecular gas in external galaxies provide a means to examine the variations in galaxy structure and evolution, just as searches for bodies orbiting other stars provide additional perspectives on the formation and motions of planets. Molecular gas not only provides the raw material for star formation, but also responds more significantly than stars do to influences of large-scale dynamical structures such as bars and spiral arms. Thus, spectroscopic measures of molecular emission provide a means to trace large- and small-scale motions in addition to the distribution of gaseous material in galaxies.
The challenges facing studies of molecular gas in nearby galaxies include achieving high resolution (while retaining sensitivity to larger-scale information) and assessing the accuracy of various tracers in mapping out the more abundant, but more elusive, molecular hydrogen. In this presentation, I will show recent results mapping out molecular gas in galaxies, chiefly through CO emission and dust extinction, and discuss their connection to star formation and galaxy evolution. In addition, I will outline prospects for future studies of molecular gas and star formation in nearby galaxies.