Unit:
Κατεύθυνση Αστροφυσική, Αστρονομία και Μηχανική (ΒΑΣΙΚΗ ΦΥΣΙΚΗ)Library of the School of Science
Author:
Paraschos Georgios-Filippos
Supervisors info:
Δέσποινα Χατζηδημητρίου, Αναπληρώτρια Καθηγήτρια, Τμήμα Φυσικής, ΕΚΠΑ
Καλλιόπη Δασύρα, Επίκουρη Καθηγήτρια, Τμήμα Φυσικής, ΕΚΠΑ
Original Title:
Spatially resolved excitation study of CO molecules in active galactic nuclei
Translated title:
Spatially resolved excitation study of CO molecules in active galactic nuclei
Summary:
Jet activity and interactions with the ISM, like jet-cloud collisions, as well as energy deposition of the jet into the ambient ISM can be studied using spatially resolved observations of the CO excitation. In this thesis we aim to study this interaction between jets, originating from black holes, and the ambient, molecular gas and ISM. To do this we study three radio galaxies: OQ 208, 4C 12.50 and IC 5063, using observations from ALMA, SMA and the Plateau de Bure.
We create maps of the kinetic and excitation temperatures, number density, column density, pressure and optical depth by comparing the fluxes of each individual pixel to the theoretical fluxes calculated by the RADEX code.
Our first target, galaxy OQ 208, exhibits a temperature gradient of 10K between the nucleus and the rest of the gas. This result is typical for a spiral galaxy but not particularly indicative of jet activity.
Our second target is galaxy 4C12.50 for which a CO wind has been observed. We aimed to translate the high excitation of the circumnuclear gas, that coincides with a wind location, into a temperature.
Our last target is galaxy IC 5063, a primary example for which analytical calculations have been carried out in a spatially resolved manner and have shown that the jet impacted regions reach a kinetic temperature of ∼200K. We confirm this result, whether the gas is presumed to be in LTE or not.
Overall we find that jets can indeed impact the ambient ISM, causing the temperature to rise as a high as a whole order of magnitude. This difference in temperature can have an impact in the detectability of winds but also in their mass content, as it can affect the αCO CO to H2 conversion factor.
Main subject category:
Science
Keywords:
CO molecule, jets, excitation, radio galaxies, OQ208, 4C12.50, IC5063, AGN
