Frontier Research in Astrophysics and Particle Physics: "A ~50 million lightyear warm/hot emission filament crossing through the A3391/95 galaxy cluster system" by Thomas H. Reiprich

Start date: 14/01/2022 10:45 End date: 14/01/2022 11:45

​"On top of the riddles of dark matter and dark energy, we are faced with the problem that a significant fraction of the normal matter ("baryons") is "missing" at low redshift. Luckily, cosmological hydrodynamical simulations suggest a straightforward solution to this missing baryon problem: the baryons should reside in large scale filaments connecting galaxy clusters. They are expected to occupy a region in density and temperature space that is hard to detect observationally, though. The low temperature (~10^5 K) portion of this "warm-hot intergalactic medium" (WHIM) has indeed been found through UV absorption spectroscopy of background quasars. Nevertheless, the high-temperature (~10^6 K) fraction of these missing baryons remains elusive, especially when trying to trace it spatially resolved in emission because of the lack of sensitive instruments in the soft-X ray band. In one of the first observations taken with the new eROSITA telescope we have now discovered a ~50 million lightyear emission filament — the longest such filament ever observed in an individual system. Its appearance resembles closely the expectations from simulations; therefore, our results show that baryons indeed reside in large-scale warm-hot gas filaments with a clumpy structure. In this talk, I will discuss these findings, as well as a few other discoveries from these eROSITA data and from accompanying DECam optical data and ASKAP/EMU radio data". Prof. Dr. Thomas H. Reiprich (University of Bomm).

The seminar will be held remotely via zoom due to travel restrictions: Frontier Research in Particle Physics and Astrophysics Master seminars - Aula 10 Ciencias.

We recall you the format:
First part:
- The speaker gives a talk of approximately 50 minutes
- Open session of approximately 10 minutes for questions from the 
general public (non master students)

Second part: 

After this, the general public is dismissed, and the speaker will remain with the students (and any master professor who wishes to stay) for an informal discussion which lasts approximately 30 minutes.

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