A Practical Overview of Stellar Spectroscopy and Abundance Analysis
I will present a brief and practical overview of stellar spectroscopy and abundance analysis using high resolution spectroscopic data. First, I will briefly explain some basic concepts and ingredients to understand how to derive atmospheric parameters and chemical abundances from a stellar spectrum. Then I will illustrate the process doing a real time analysis of real spectra with the code iSpec (Blanco-Cuaresma et al. 2014).
Active galactic nuclei (AGN) are the most powerful long standing phenomena in the universe. Among them, the most extreme sources display ultra relativistic particle jets which radiate over the full electromagnetic spectrum, from radio to very high energies (E > 100 GeV). The cosmological distances of these sources make very difficult to decipher the location and origin of their high energy emission, which remains one of the major not (fully) answered question of this research field.
I will show how the parsec-scale imaging from radio very-long-baseline-interferometry (VLBI) observations coupled to broadband spectral models and hydrodymamic jet simulations lead us toward and updated unification scheme of the jetted AGN phenomenon.