|Speaker||Talk Date||Talk Series|
|Guillermo Tenorio-Tagle, INAOE, Mexico||12 November, 2009||Institute of Astronomy Colloquia|
I will review the main properties of young superstar clusters (SSCs)
and then show that there are two different stationary hydrodynamic
solutions for the matter re-inserted by the plethora of massive stars that, as they evolve, undergo strong winds and eventually explode as supernovae.
One of the solutions is a full stationary wind. This has a strong impact on the interstellar medium. I will show that the structure of Giant HII regions and HII galaxies is caused by a
dramatic competition between the two negative feedback events: the mechanical energy and the UV ionizing radiation arising from SSCs.
The second hydrodynamical solution, now called the bimodal solution, is unavoidable for the more dense and compact clusters. In these cases, the cluster wind is
much smaller than what it has been predicted by synthesis models. The
fact is that
the densest central regions become strongly radiative, what depletes
rapidly their pressure,
making them unable to reach the required speeds to participate in a
In these cases the re-inserted matter accumulates within the cluster
causing a positive star formation feedback, as gravity overcomes this matter