Extended UV (XUV) Emission in Nearby Galaxy Disks

Gil de Paz, A.; Thilker, D. A.; Bianchi, L.; Aragón-Salamanca, A.; Boissier, S.; Madore, B. F.; Díaz-López, C.; Trujillo, I.; Pohlen, M.; Erwin, P.; Zamorano, J.; Gallego, J.; Iglesias-Páramo, J.; Vílchez, J. M.; Mollá, M.; Muñoz-Mateos, J. C.; Pérez-González, P. G.; Pedraz, S.; Sheth, K.; Kennicutt, R. C.; Swaters, R. A.
Bibliographical reference

Formation and Evolution of Galaxy Disks ASP Conference Series, Vol. 396, Proceedings of the conference held 1-5 October, 2007 at the Centro Convegni Matteo Ricci, Rome, Italy. Edited by José G. Funes, S.J., and Enrico Maria Corsini. San Francisco: Astronomical Society of the Pacific, 2008., p.197

Advertised on:
10
2008
Number of authors
21
IAC number of authors
0
Citations
4
Refereed citations
4
Description
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)<5 mag] 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 H I but relatively poor in molecular gas, have stellar populations with luminosity-weighted ages of ˜1 Gyr, and ionized-gas metal abundances of ˜Z_{&sun;}/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.