Open AccessSpectral and morphological properties of quasar hosts in smoothed particle hydrodynamics simulations of active galactic nucleus feeding by mergers
Author(s) -
Cattaneo A.,
Combes F.,
Colombi S.,
Bertin E.,
Melchior A.L.
Publication year - 2005
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2005.09003.x
Subject(s) - physics , smoothed particle hydrodynamics , astrophysics , galaxy , galaxy merger , active galactic nucleus , quasar , black hole (networking) , galaxy formation and evolution , population , elliptical galaxy , astronomy , galactic nuclei , computer network , routing protocol , routing (electronic design automation) , demography , sociology , computer science , link state routing protocol
We present a method for generating virtual observations from smoothed particle hydrodynamics simulations. This method includes stellar population synthesis models and the reprocessing of starlight by dust to produce realistic galaxy images. We apply this method and simulate the merging of two identical giant Sa galaxies ( M disc = 10 11 M ⊙ , M spheroid = 2.5 × 10 10 M ⊙ ) . The merger remnant is an elliptical galaxy ( M spheroid ≃ 1.3 × 10 11 M ⊙ , M disc ≃ 7.4 × 10 10 M ⊙ ) . The merger concentrates the gas content of the two galaxies into the nuclear region. The gas that flows into the nuclear region refuels the central black holes of the merging galaxies. We follow the refuelling of the black holes during the merger semi‐analytically. In the simulation presented in this paper, the black holes grow from 3 × 10 7 to 1.8 × 10 8 M ⊙ , with a peak active galactic nucleus (AGN) luminosity of M B ∼−23.7 . We study how the morphological and spectral properties of the system evolve during the merger, and we work out the predictions of this scenario for the properties of host galaxies during the active phase. The peak of AGN activity coincides with the merging of the two galactic nuclei and occurs at a stage when the remnant looks like a lenticular galaxy. The simulation predicts the formation of a circumnuclear starburst ring/dusty torus with an opening angle of 30°– 40° and made of clouds with n H = 10 24 cm −2 . The average optical depth of the torus is quite high, but the obscuring medium is patchy, so that there still exist lines of sight where the AGN is visible in a nearly edge‐on view. For the same reason, there are lines of sight where the AGN is completely obscured in the face‐on view.