Seminar by Dr Wonju Kim

Ionized and photodissociation regions toward ATLASGAL dust clumps

Dr WonJu Kim recently defended her PhD which focused on statistical studies of high-frequency radio recombination lines associated with compact HII region. Dr Kim is visiting Dr Urquhart over the next week to work on ALMA projects. She will be giving a seminar on the 2nd Oct. on her thesis work. The outline of the talk is given below and the slides can be obtained here.

Abstract:

Ionised hydrogen (HII) regions are an excellent indicator of high-mass star-forming regions and ongoing star formation in galaxies. Powerful outflows from O/B stars in their early stages and, throughout their whole life, intense ultraviolet (UV) radiation and stellar winds appreciably alter the chemical composition of the ISM in their vicinity and turn the surfaces of molecular clouds into photodissociation regions (PDRs).
I will present two studies about HII regions and PDRs associated with high-mass star-forming clumps (967 ATLASGAL clumps). The first part of the talk focuses on an extensive survey of HII regions using (sub)millimetre hydrogen radio recombination lines (submm-/mm-RRLs) observed with the IRAM 30m, Mopra 22m, and APEX 12m telescopes. This survey covers the largest sample of (sub)mm-RRL detection published to date. The RRLs show association with young HII regions and molecular clumps and provide unique velocity information of ionised gas associated with dust clumps.
In the second part, I will present the IRAM 30m observations of eight molecular tracers of PDRs, namely HCO, HOC+, C2H, cyclic-C3H2, CN, H13CN, HC15N, and HN13C as well as C18O and H13CO+. Some of the molecules (HCO, C2H, and cyclic-C3H2) show correlations of their column densities and abundances with the presence of HII regions. The correlations possibly imply that the abundances of molecules vary in molecular clumps including different circumstances.