Co-evolution of black hole growth and star formation activity in local luminous infrared galaxies

Type Conference Paper
Names A. Alonso-Herrero, M. Pereira-Santaella, G. H. Rieke, D. Rigopoulou, A. M. Diamond-Stanic, A. Hernán-Caballero, Y. Wang
Proceedings Title Highlights of Spanish Astrophysics VII
Conference Name Proceedings of the X Scientific Meeting of the Spanish Astronomical Society (SEA)
Place Valencia, Spain
Pages 103-114
Date May 1, 2013
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Abstract We use Spitzer spectroscopic and imaging observations to study the co-evolution of black hole (BH) growth and star formation (SF) activity in a complete volume-limited sample of local Luminous Infrared Galaxies (LIRGs). Using a mid-infrared (mid-IR) spectral decomposition method we identify active galactic nuclei (AGN) with Seyfert-like luminosities and relatively small bolometric contributions (median ˜ 5%) in half of the LIRG nuclei. Combining mid-IR and AGN optical detections we obtain a 62% AGN detection rate in local LIRGs. We combine gas velocity dispersions of spectrally resolved [Ne III]15.56 μm and [OIII]λ5007 ̊A lines and literature stellar velocity dispersions , and we obtain typical BH masses of 3 × 10{^7} solar masses for local LIRGs. We find that the ratios of nuclear and integrated SF rates (SFR) to BH accretion rates are higher in local LIRGs than in optically selected Seyferts. We interpret our results in a scenario where local LIRGs with an AGN represent an early phase of the (possibly episodic) growth of BHs in massive spiral galaxies with high SFR, not necessarily associated with a major merger event.
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