1. Extended UV (XUV) Emission in Nearby Galaxy Disks
- Author
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de Paz, A. Gil, Thilker, D. A., Bianchi, L., Aragon-Salamanca, A., Boissier, S., Madore, B. F., Diaz-Lopez, C., Trujillo, I., Pohlen, M., Erwin, P., Zamorano, J., Gallego, J., Iglesias-Paramo, J., Vilchez, J. M., Molla, M., Munoz-Mateos, J. C., Perez-Gonzalez, P. G., Pedraz, S., Sheth, K., Kennicutt Jr, R. C., Swaters, R., and Team, the GALEX Science
- Subjects
Astrophysics - Abstract
We summarize the main properties of the extended UV (XUV) emission found in roughly 30% of the nearby spiral galaxies observed by the GALEX satellite. Two different classes of XUV disks are identified, the Type 1 XUV disks where significant, structured UV-bright features are found beyond the "classical" azimuthally-averaged star-formation threshold, and the Type 2 XUV disks, which are characterized by very extended (seven times the area where most of the stellar mass is found), blue [(FUV-K)<5mag] outer disks. These latter disks are extreme examples of galaxies growing inside-out. The few XUV disks studied in detail to date are rich in HI but relatively poor in molecular gas, have stellar populations with luminosity-weighted ages of ~1 Gyr, and ionized-gas metal abundances of ~Zsun/10. As part of the CAHA-XUV project we are in the process of obtaining deep multi-wavelength imaging and spectroscopy of 65 XUV-disk galaxies so to determine whether or not these properties are common among XUV disks., Comment: 4 pages, 2 figures, to appear in the proceedings of "The Formation and Evolution of Galaxy Disks", Rome 2007, organized by the Vatican Observatory, editors J. G. Funes, S.J. and E. M. Corsini
- Published
- 2008