Rediscovering the hydrogen atom

Date and time
17 Jun 2008 - 00:00 Europe/London
Address

Aula

Talk language
English
Slides language
English
Description

Common wisdom identifies hydrogen lines in photoionized region with recombination lines. However, these lines can also be excited by different atomic mechanisms, the most important of which are collisional excitation and continuum pumping by stellar photons. The relative contributions of these two mechanisms to the total Balmer intensity can be substantial in certain environments, and the associated bias can easily dominate the error budget. In this talk I will give estimates for the effectiveness of these mechanisms, defining at the same time the observational strategies that permit to minimize their contribution.