Exchange Report by Silke Andree-Labsch


For my doctoral degree I  worked on a three-dimensional PDR model which is based on the KOSMA-τ PDR code. Before I started my stay in Tel Aviv I finished programming of the main parts of this model and tested it using observations of the Orion Bar PDR.

Another aim was a more detailed understanding of the behaviour of some of the important chemical species.

Prof. Amiel Sternberg, whose workgroup I visited, has contributed to the initial version of the KOSMA-τ PDR model (the τ stands for Tel Aviv University) and has extensive experience on chemical networks in the ISM. Therefore, I applied for the three month stay in his workgroup.

Organisation and visa chaos

I arrived at Tel Aviv airport at late night between 10th and 11th May 2014. Usually, based on the experience of colleagues and from my first stay in January, visiting at the University is possible with the tourist visa one gets when entering Israel. However, this time I was less lucky and I was told that if I want to work at the university – even if I am not paied in Israel - I would need a student visa (which I did not have). After some late night discussion at the interiour office at the airport I got a tourist visa for the first month of my stay which I had to extend with a student visa within this month. This caused some paperwork, but, with help of the people of my hosting institut (thank you!), I solved the problem.

Except for the visa chaos the organisational effort for my stay was very low, especially as I got one of the university guest rooms. Finding a room in Tel Aviv on the free market on (more or less) short notice is supposed to be very hard.

Life in Tel Aviv

Tel Aviv city and University are amazing places to stay. The University has a beautiful campus including palm gardens and a lot of places to sit outside and enjoy the hot weather. The city itself offers heaps of possibilities concerning shopping and restaurants and of course nice beaches for the weekends.

During my first week in Tel Aviv I learned that even without being registered as a Tel Aviv student I could sign up for sports courses after paying some fee. I joined the Judo course, which I enjoyed a lot. Furthermore, I was invited into an international people soccer group which meets in a park close to the sea (usually I am not a big soccer player, but next to the beach at sunset it's a nice experience).

During the last weeks of my stay, unfortunately, the Israel-Gaza conflict escalated again. Although I did not feel seriously in danger in Tel Aviv I had to learn to deal with air raid sirens and bomb shelters. However, the daily life went on close to normal and I decided to stay and go on working.


At about half time of my stay a friend from home visited me. Together we went for a weekend bus trip to Jerusalem, Masada and the Dead Sea. We enjoyed a full day in Jerusalem visiting numerous impressive places of religious and historical significance. The next day we went to the ancient fortification Masada in the Judaean Desert and finally after two days of walking and hiking in the heat, spent some time relaxing and floating in the Dead Sea.

Scientific work

In my „Tel Aviv Project“ I investigated HI column densities which form at the surface of irradiated molecular clouds. Some analytic results on this topic exist, however, comparison to simulations, in the context of spherical geometries, is still lacking. This gap can be filled using the KOSMA-τ PDR code. If time allows, this project could be also extended to CII column densities. This work nicely combines application of the KOSMA-τ code, with which I am familiar, with new analytic results from the Tel Aviv working group which are mainly new and hence very educative for me. At the end of my stay I had some interesting results which we are planning to publish and which will become a part of my thesis.

Left: Trip to Jerusalem / Right: View on Tel Aviv University campus (there are palm trees on the campus!) from the roof of the physics department

Current position

Since 2016 Silke works as Data Science Consultant at Bayer Business Services.