Multi-wavelength studies of a representative AGN sample in the local Universe.


Thesis Supervisors at ESO: Paola Andreani & Evanthia Hatziminaoglou

Abstract

Nearby Seyfert galaxies offer an ideal laboratory to study the co-existence and interaction of star formation and accretion onto supermassive black holes. The study of the distribution, dynamics and kinematics of the gas both molecular and in the atomic phase is key to determine the role of outflows driven by Active Galactic Nuclei (AGN), infall motions around the AGN and the global AGN feeding and feedback impacting galaxy evolution.

What is also important is to study the distribution of the nuclear star formation, the amount of dense molecular gas and the excitation status of the gas, and how this gas is connected to the star formation activity in these galaxies.
The goal of this project is the statistical study of the dynamics uncovered with molecular and atomic lines of the interstellar medium and circumnuclear medium of a complete sample of 34 AGN in the Local Universe (D=10-50Mpc), from the 12μm all-sky sample, consisting of 14 type 1 AGN, i.e. Seyfert 1 and Hidden Broad Line Region galaxies, and 20 Seyfert 2). These will be compared to a sample of 7 Low-Ionisation Nuclear Emission-line Regions (LINERs) with archival ALMA data. The CO(2-1) transition has been observed with ALMA in the central 3 kpc of all the objects in the sample.

To complement this dataset spectroscopic observations (i.e. CO(3-2) and CO(1-0)) have to be dug out from the ALMA archive, as well as data from other archives, such as HST, Herschel, optical IFU spectra etc.

The project consists of various steps, that include:

1. Collection of ancillary data in radio (VLA, ATCA) far-infrared (Herschel), optical (HST); creation of a database to store the data along with their (queryable) metadata. This database will become publicly available towards the end of the PhD project.
2. Study of the dynamics (outflows, inflows, rotation, mass accretion, etc) as traced by the CO(2-1) line as well as other emission (or eventual absorption) lines, understand the role of each component and the relationship to the other tracers.
3. A byproduct of this project will be to derive the physical properties of the ISM from the line ratios of the different species; the gas depletion time and the star formation activity of these objects.

This project offers the possibility to collaborate with colleagues in Italy, the UK and the US, that are part of the larger collaboration. It also provides the opportunity to learn ALMA data reduction from ALMA experts, as well as build experience in writing observing proposals in a multitude of facilities for follow up observations.