Thesis

Reconstruction of the mass assembly history of Active Galactic Nuclei with FADO

• Call:

  IDPASC Portugal - PHD Programme 2019

• Academic Year:

  2019 / 2020

• Domain:

  Astrophysics

• Supervisor:

  Jean Michel Gomes

• Co-Supervisor:

  Polychronis Papaderos

• Institution:

  Universidade do Porto

• Host Institution:

  Universidade do Porto

• Abstract:

  Fitting Analysis using differential evolution Optimization (FADO) is a conceptually novel, publicly available spectral population synthesis (PS) code (www.spectralsynthesis.org), which employs for the first time genetic optimization and artificial intelligence to identify the star-formation and chemical evolution history (SFH and CEH, respectively) that self-consistently reproduce the main nebular characteristics of star-forming (SF) galaxies. This unique concept allows us to alleviate and even overcome, degeneracies in spectral synthesis studies, thereby opening new avenues to the investigation of galaxy formation and evolution. However, a large fraction of emission-line galaxies hosts an Active Galactic Nucleus (AGN) powered by accretion of matter onto a central super-massive black hole of several million solar masses. Depending on our viewing angle to the galaxy nucleus and its surrounding obscuring torus, the strong non-stellar radiation from the AGN can provide an important fraction, or even outshine, the spectral continuum of the underlying galaxy host. Even a low-to-moderate (~20%) contribution of the AGN to the optical continuum emission of a galaxy can strongly bias conclusions drawn from state-of-the-art purely-stellar PS codes, as demonstrated in Cardoso, Gomes & Papaderos (2016,2017). The work tasks and main objectives of this Ph.D. thesis are to use FADO in order to: 1 - Quantify its accuracy with benchmark tests in retrieving the SFH & CEH in the presence of an AGN. Additionally, compare the results from FADO with those from purely stellar codes (e.g., STARLIGHT, STECKMAP, ULySS, FIREFLY). In this task, the student will make use of fictitious datasets created with the REBETIKO evolutionary synthesis code under the presence of an AGN; 2 - Disentangle the star-forming component from the non-thermal AGN component and estimate the AGN luminosity emission in various spectral bands; 3 - Test distinct recipes in modeling the spectral energy distribution of the AGN, like the inclusion of multi-component continuum (e.g., Ferland et al. 2017 - Big Blue Bump and distinct power-law slopes in the X-ray, UV and optical). The student will make use of the FADO AGN module; 4 - fit galaxy spectra data sets from SDSS & GAMA surveys as well as Integral Field Spectroscopy data from MUSE, MEGARA, MaNGA to investigate the SFH & CEH of galaxies hosting an AGN. This project provides an excellent combination of astrophysical theory with observations, and it will lead to valuable expertise and several publications that will support the future career of the student. Preferable computing languages are Fortran, IDL and/or Python.