Résumé / Abstract Journal-club_Galaxies

Séminaire/Seminar Galaxies

« Energy budget of galaxies: shocks and photo-dissociation regions (PDR) in 3C 326 »

Jorge Andres Villa Velez
Département de Physique, Ecole Normale Supérieure de Paris (Paris, France)

Shocks are ubiquitous in the interstellar medium (ISM) as a result of a variety of astrophysical phenomena such as outflows, supernovae, jets, and accretion among others. The perturbations created by these phenomena traverse the ISM, disturbing and changing the thermal, chemical, and physical characteristics of the environment. Therefore, understanding the underlying physics of shocks provides us with a powerful tool to study how energy is dissipated in extragalactic sources by shocks. In this talk, I will present a research project focused on the interpretation of H2 molecular emission (e.g., pure rotational and ro-vibrational transitions) in radiogalaxies observed with the Spitzer IR Spectrograph and VLT/SINFONI imaging spectroscopy assuming the emission is produced by ensembles of shocks/PDRs inside the observation beam. Particularly, we focused on the radio galaxy 3C 326, a galaxy with low star formation (0.07 Msun/yr) and large amounts of H2 (3.5x10^9 Msun). The fitting method is purely based on the H2 lines but comparisons with other lines which can trace shocks and PDRs are performed. As a preliminary result, the mechanical and UV power is found to be mostly reprocessed by the diffuse medium (i.e., nH = 10-100 cm^-3). Also, the derived mechanical power seems to be independent of the medium that reprocesses this energy. This is a novel method that allows us to obtain the mechanical and UV contribution to the total energy budget of the galaxy from observations. The impact of this study opens a door to understanding energy dissipation in extragalactic sources produced by ensembles of shocks/PDRs in a multiwavelength context being a key point to exploit and interpret future JWST observations and to put constraints on feedback and dissipation processes.
jeudi 20 avril 2023 - 11:30
Amphithéâtre Henri Mineur
Institut d'Astrophysique de Paris
Page web du séminaire / Seminar's webpage