My research field deals with the formation of high mass stars. I am interested in the role of already formed high mass stars (and their associated ionized – HII – regions) on the possible formation of a new generation of (high mass) stars. The many available infrared and submillimetre surveys have revealed the important of HII regions in the promotion of (high) mass star formation. We have studied this phenomenon for more than 15 years. Our first interest was to characterize the properties of the young stellar population observed at the edges of HII regions (Deharveng et al. 2005). Then, with the Herschel Observatory we have observed the youngest population of stars and characterize the possible importance of this phenomenon of star formation triggered by HII region in part of the Galactic Plane using the Herschel Hi-GAL survey (Palmeirim et al. 2017). The Herschel Observatory has revealed the importance of filaments in the star formation process. Using the ArTéMis camera on APEX we observed the Galactic HII region RCW 120 to study the filamentary structure of its photodissociation region (Zavagno et al. in prep). We have shown that the edges of this HII region is filamentary and that the filaments’ profile show a clear asymmetry due to the radiative compression of the HII region. This compression might play a role in the future properties of cores formed in the filaments, which will host the star formation. For example, this compression can limit the fragmentation at the early stages and favour the formation of high mass stars as seen with ALMA (Figueira et al. 2018).
In June 2019, a meeting in Naplio was organized by S. Dib and D. Polychroni. This meeting entitled “Zooming in on Star Formation” was dedicated to the most recent results in numerical simulations and observations on the formation of stars and planets. I was invited to this meeting to give a talk on the feedback from HII regions on star formation. I presented the most recent results we obtained in this field, including the limited fragmentation observed at early stages of high mass star formation at the edges of RCW 120 obtained with ALMA and the filaments’ profile obtained with ArTéMiS on APEX. The RadioNet support allowed me to obtain the data with APEX using the Transnational Access program and additionally to attend this conference. There I discussed with people doing numerical simulations of ionized regions and we plan to develop new-dedicated models to quantify the feedback of HII regions on impacting the properties of filaments and cores located at their edges.
The RadioNet support is really useful to develop communication, starting of new collaborations and training actions in the community of radio astronomers. This support allowed me to attend this conference, present recent results and start new collaborations.
Annie Zavagno is a professor at Aix Marseille Université and she does her research at the Laboratoire d’Astrophysique de Marseille since 1997 when she has been recruited as assistant professor. She obtained her PhD from the Paris Diderot (Paris 7) Université in 1993.
Image (C) S. Dib