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astro-ph2001
When Photoionization Is Not Enough
Sueli M. Viegas
It is well-known that photoionization is the major mechanism powering nebulae emission-lines. For about 30 years, numerical simulations using photoionization codes have been employ…
astro-ph2000
On the Abundance Gradient of the Galactic Disk
Lucimara P. Martins, Sueli M. M. Viegas
Estimates of the gas temperature in planetary nebulae obtained from the [O III] emission line ratio and from the Balmer discontinuity indicate differences reaching up to 6000 K (Li…
astro-ph1999
Infrared line ratios revealing starburst conditions in galaxies
Sueli M. Viegas, Marcella Contini, Thierry Contini
The physical conditions in typical starburst galaxies are investigated through critical infrared (IR) line ratios, as previously suggested by Lutz et al. (1998, A&A, 333, L75). The…