Surround & Squash: The Interstellar Medium around Scorpius Centaurus OB2
  We exploited observational constraints on stars, gas and nucleosynthesis
ashes for the closest region of recent massive-star formation,
Scorpius-Centaurus OB2, and combined them with 3D hydrodynamical simulations,
in order to address physics and history for the case of the Scorpius-Centaurus
superbubble. We used published cold gas observations through PLANCK survey data
processing, HERSCHEL and APEX, continuum and molecular line observations. We
analysed the Galactic All Sky Survey (GASS) to investigate shell structures in
atomic hydrogen, and used HIPPARCOS and Gaia data in combination with
interstellar absorption against stars to obtain new constraints for the
distance to the Hi features. Hot gas is traced in soft X-rays via the ROSAT all
sky survey. Nucleosynthesis ejecta from massive stars were traced with new
INTEGRAL spectrometer observations via 26Al radioactivity. We also performed 3D
hydrodynamical simulations for the Sco-Cen superbubble. To investigate the
impact of massive star feedback on extended clouds, we simulate the interaction
of a turbulent cloud with the hot, pressurised gas in a superbubble. The hot
gas fills the tenuous regions of the cloud and compresses the denser parts.
Stars formed in these dense clumps would have distinct spatial and kinematic
distributions. The combined results from observations and simulations are
consistent with a scenario where dense gas was initially distributed in a band
elongated in the direction now occupied by the OB association. Superbubbles
powered by massive stars would then repeatedly break out of the elongated
parent cloud, surround and squash the denser parts of the gas sheet and thus
induce more star formation. The expected spatial and kinematic distribution of
stars is consistent with observations of Sco-Cen. The scenario might apply to
many similar regions in the Galaxy and also to AGN-related superbubbles.
