On the feedback from super stellar clusters. I. The structure of giant HII regions and HII galaxies.  

Guillermo Tenorio-Tagle, Instituto Nacional de Astrofísica Óptica y Electrónica, AP 51, 72000 Puebla, México, gtt@inaoep.mx  gtt@iaa.es  
Casiana Muñoz-Tuñón, Instituto de Astrofísica de Canarias, E 38200 La Laguna, Tenerife, Spain, cmt@ll.iac.es 
Enrique Pérez, Instituto de Astrofísica de Andalucía (CSIC), Camino bajo de Huetor 50, E 18080 Granada, Spain, eperez@iaa.es 
Sergej Silich, Instituto Nacional de Astrofísica Óptica y Electrónica, AP 51, 72000 Puebla, México, silich@inaoep.mx
Eduardo Telles, Observatório Nacional, Rua José Cristino 77, 20921-400, Rio de Janeiro, Brazil, etelles@on.br 

Abstract.  We review the structural properties of giant extragalactic HII regions and HII galaxies based on  two dimensional hydrodynamic calculations, and propose an evolutionary sequence that accounts for their observed detailed structure. The model assumes a massive and young stellar cluster surrounded by a large collection of clouds. These are thus exposed to the  most important star-formation feedback mechanisms:  photoionization and the cluster wind. The models show how the two feedback mechanisms compete with each other in the disruption of clouds and lead to two different hydrodynamic solutions: The storage of clouds into a long lasting ragged shell that inhibits the expansion of the thermalized wind, and the steady filtering of the shocked wind gas through channels carved within the cloud stratum. Both solutions are here claimed to be concurrently at work in giant HII regions and HII galaxies, causing their detailed inner structure. This includes multiple large-scale shells, filled with an X-ray emitting gas,  that evolve to finally merge with each other, giving the appearance of shells within shells. The models also show how  the  inner  filamentary structure of the giant superbubbles is largely enhanced with matter ablated from clouds and how cloud ablation proceeds within the original cloud stratum. The calculations point at the initial contrast density between the cloud and the intercloud media as the factor that defines which of the two feedback mechanisms becomes dominant throughout the evolution. Animated version of the models presented can be found at http://www.iaa.csic.es/~eperez/ssc/ssc.html


Astrophysical Journal 2006, vol. 643, p. 186.         Full manuscript in PDF format (1.11 MB).


The animations corresponding to the different cases described in this work can be found here, in the form of animated GIF files.  



Case C. Cloud density, nc=1000 cm-3. Photoionization plus stellar wind. 
  • Full frame (194 pc x 194 pc) 2D animation of density and temperature evolution.  (4.1MB)
  • A slower version (0.2s delay between frames). (4.1MB)
  • A zoomed in (80 pc x 80 pc) version. (6.3MB)


Case D. Cloud density, nc=100 cm-3. Photoionization plus stellar wind.  
  • Full frame (194 pc x 194 pc) 2D animation of density and temperature evolution.  (2.1MB)
  • A slower version (0.2s delay between frames). (2.1MB)
  • A zoomed in (80 pc x 80 pc) version. (3.5MB)


This page updated 20060711 by ES.Enrique