סמינר באסטרונומיה ובאסטרופיזיקה: Hot Stars and Extreme Radiation Fields in a Local Starburst: JWST opens Pandora's Box

Zoom: https://tau-ac-il.zoom.us/j/81850414917?pwd=hOoiUteqh6KKoO6pzUfM8jmYjZJWZP.1

Abstract:

The great nebula in NGC 5253 holds the hottest young stars in the Local Universe and the most concentrated young star cluster, with ~1000 O stars in ~3 pc^3.   In Cycle 1 of JWST we took the full 5-28 micron spectrum of the NGC 5253 starburst; the goals were to determine the radiation field of the intense cluster and how it has affected the surrounding regions.  The results were much more extreme and complex than expected.  We find unusual PAH and continuum features that trace dust processing by intense radiation and possible dispersion by embedded Wolf-Rayet stars.  30 HI recombination lines are detected and give a flat extinction over the whole infrared range.  Besides the usual starburst suite of  ionic emission lines, the main cluster has very high excitation lines more typical of SNR and AGN.  In spite of the ~35 magnitudes of extinction, we see ~25% of the high excitation photons escape from the main cluster and excite smaller clusters over the  ~100 pc field.   The new power JWST brings to infrared spectroscopy will be as revolutionary as its images.

מארגן הסמינר: ד"ר יהונתן שטרן