Travel support for two observers to conduct astronomical observations at the LBT during June 2019

• Applicant: Privatdozent Dr. Dominik Bomans
• Subject Area: Astrophysics and Astronomy
• Term: Funded in 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 431668537

1) The observation of nebular CIII] and CIV emission lines in z~7galaxies triggered new interest in the nature of the hard radiation fieldneeded for this emission lines to occur. Since not only very massive,low metallicity stars, but also massive X-ray binaries, accretingsupermassive black hole, and even shocks may be possible sourcesof the hard continuum photons, the definition of a set of very localproxies is imperative, where spatial resolution and sensitivity allow adetailed study of the gas and individual ionization sources. 2) Theionization process of outflows and diffuse ionized gas halos in diskgalaxies is still an unsolved puzzle. While a connection to starformation activity seems to be well established (but not fullyunderstood), the ionization mechanism of the observed ionized gas isnot well constrained: while photo-ionization certainly contributes, theobserved line ratios and their change with distance from the diskrequire changes in the photon field and the presence of an additionalcurrently unknown heating mechanism. 3) Spitzer and alsoHERSCHEL revealed a significant number of small bubbles in theMilky Way. In a couple of cases, it was possible to take optical spectraof the apparent central stars, which surprisingly often turned out to beevolved massive stars (Wolf-Rayet stars, candidates for LuminousBlue Variables, and OB supergiants). We target the bubbles and theircentral stars with LUCI NIR spectroscopy to classify the potentiallyhighly absorbed part of the bubbles and investigate their evolutionarystate and their central stars in a more unbiased way.

• DFG Programme: Research Grants