Symposium S8  26-27 June 2019

Resolving the Ionized ISM

News: Registration is now open for contributed talks and posters!

Aims and scope

The ionized interstellar medium (ISM) plays a crucial role in the cycling of baryons within galaxy disks. Newly formed massive stars inject radiative and mechanical energy that serves to both trigger and suppress additional star formation, and in their end phase chemically enrich the local environment. These processes are traced through the ionized gas emission lines, which provide diagnostic information on the physical conditions (dynamics, chemical abundance, ionization state, density) of the ISM. With the revolution in optical spectroscopy brought about by the advent of many new integral field spectographs (e.g. MUSE, KCWI), newly established large sample surveys (e.g. CALIFA, MaNGA, SAMI) and planned upcoming emission line surveys (PHANGS, SDSSV/LVM, SIGNALS), we can now resolve in detail the structure of the ionized ISM across many galaxies in the Local Volume with a wealth of emission line diagnostics. This allows us to connect the large scale galaxy environments (spiral arm, interarm, bar) with the small scale (<100pc) physics.

This symposium aims to bring together Galactic and extragalactic observers, as well as simulators and modelers, working at the sub-100 pc scales that resolve individual HII regions and other ionization structures. The two key topics we will address are mapping gas phase metallicities (both across disks in 2D and within individual resolved HII regions) and resolving the ionization structure of HII regions and diffuse ionized gas. We will place these results in the context of cutting edge simulations and photoionization models, and prepare for the advances that will be enabled by future surveys.


  • Extragalactic HII regions
  • Ionized ISM in the Milky Way
  • Ionizing Massive Stars & Winds
  • Diffuse Ionized Gas
  • Photoionization modeling
  • Simulating Chemical Enrichment & Feedback in the ISM

Invited speakers

  • Danielle A. Berg (OSU, USA)
  • Paul Crowther (U of Sheffield, UK)
  • Laurie Rousseau-Nepton (CFHT, USA)
  • Emily Levesque (U Washington, USA)
  • Cesar Esteban Lopez (IAC, Spain)
  • Lisa Kewley (ANU, Australia)
  • Ralf Klessen (ITA, Heidelberg, Germany)
  • Enrique Perez-Montero (IAA-CSIC, Spain)
  • Sebastian Sanchez (UNAM, Mexico)
  • Kenneth Wood (University of St Andrews, Scotland)

Scientific organisers

Kathryn Kreckel, MPIA (chair); I-Ting Ho, MPIA (co-chair); Guillermo Blanc, Carnegie Observatories; Laurie Rousseau-Nepton, CFHT; Evan Skillman, U Minnesota; Christy Tremonti, U Wisconsin-Madison


kreckel @

Updated on Thu Jan 24 09:15:51 CET 2019