Origin of high-ionization lines found in extremely metal poor galaxies.
Speaker: Shun Hatano
Abstract:
The extreme metal poor galaxies (EMPG) exhibit intense high-ionization emission lines, such as He II4686, unexplained by stellar synthesis models. Umeda et al. (2022) employed CLOUDY and MCMC to reproduce the observed spectrum, revealing an unidentified non-thermal radiation source. In this study, we introduce [Ne V]3426 emission (97.1 eV) and estimate spectral indices and luminosities for EMPGs in the 54.4-97.1 eV range. Confirming that non-thermal radiation dominates the 54.4-97.1 eV range for all the galaxies with [Ne V]3426 detections, we discuss the origin of the non-thermal radiation.