The star formation history of Seyfert 2 nuclei

By R. C. Fernandes, Q. Gu, J. Melnick, E. Terlevich, R. Terlevich, D. Kunth, R. R. Lacerda, B. Catarina, Brazil, N. University and 7 more. 2004

238 citations recorded by the source corpus.

We present a study of the stellar populations in the central ∼200 pc of a large and homogeneous sample comprising 79 nearby galaxies, most of which are Seyfert 2s. The star formation history of these nuclei is reconstructed by means of state-of-the-art population synthesis modelling of their spectra in the 3500‐5200 A interval. A quasar-like featureless continuum (FC) is added to the models to account for possible scattered light from a hidden active galactic nucleus (AGN). We find the following. (1) The star formation history of Seyfert 2 nuclei is remarkably heterogeneous: young starbursts, intermediate-age and old stellar populations all appear in significant and widely varying proportions. (2) A significant fraction of the nuclei show a strong FC component, but this FC is not always an indication of a hidden AGN: it can also betray the presence of a young, dusty starburst. (3) We detect weak broad Hβ emission in several Seyfert 2s after cleaning the observed spectrum by subtracting the synthesis model. These are most likely the weak scattered lines from the hidden broad-line region envisaged in the unified model, given that in most of these cases independent spectropolarimetry data find a hidden Seyfert 1. (4) The FC strengths obtained by the spectral decomposition are substantially larger for the Seyfert 2s which present evidence of broad lines, implying that the scattered nonstellar continuum is also detected. (5) There is no correlation between the star formation in the nucleus and either the central or overall morphology of the parent galaxies. Ke yw ords: galaxies: active ‐ galaxies: Seyfert ‐ galaxies: statistics ‐ galaxies: stellar content.

Subfields: Astronomy and Astrophysics, Instrumentation, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/c8e0b3dac8fb5e01d36d93a180e5fc6fc610cdb5

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Citations in the corpus

Bursty stellar populations and obscured active galactic nuclei in galaxy bulges (2007, methodology): “The E + A phenomena is also often observationally linked with the presence of an active galactic nucleus (AGN) (Kauffmann et al. 2003a; Cid Fernandes et al. 2004a; Yip et al. 2004; Bender et al. 2005; Tadhunter et al. 2005; Goto 2006; Yan et al. 2006), with direct implications for the starburst–AGN…”
BAT AGN Spectroscopic Survey. I. Spectral Measurements, Derived Quantities, and AGN Demographics (2017, methodology): “We used the data from the Hyperleda catalogue (Paturel et al. 2003) and literature references (Cid Fernandes et al. 2004; GarciaRissmann et al. 2005; Ho et al. 2009; van den Bosch et al. 2015).”
Emission-line diagnostics of low-metallicity active galactic nuclei (2006, background): “Although part of the spheroid growth mayresult from mergers of stellar disks (eg Kauffmann & Haehnelt 2000), star formation in the central regions of the galaxy is also expected to contribute to the overall growth of the bulge (Schmitt et al. 1999; Cid Fernandes et al. 2001, 2004).”
The history of star-forming galaxies in the Sloan Digital Sky Survey (2007, background): “Z⋆ plane constrained by chemical evolution arguments (see also Schmidt et al. 1991; Bica et al. 1994; Cid Fernandes et al. 2001).”
A Close Look at Star Formation around Active Galactic Nuclei (2007, background): “…Seyferts, notably Seyfert 2 galaxies, since these are the closest examples (Sarzi et al. 2007; Asari et al. 2007; González Delgado & Cid Fernandes 2005; Cid Fernandes et al. 2004; González Delgado et al. 2001; Gu et al. 2001; Joguet et al. 2001; Storchi-Bergmann et al. 2001; Ivanov et al. 2000).”
Erratum: Recovering galaxy stellar population properties from broad-band spectral energy distribution fitting (2012, methodology): “Also popular is the so-called full spectral fitting approach in which population parameters are extracted by fitting the full available spectrum (Heavens et al. 2000; Cid Fernandes et al. 2004; Ocvirk et al. 2006; Panter et al. 2007; Tojeiro et al. 2007, 2009; Chen et al. 2012) and which also requir”
Resolving the mid-infrared cores of local Seyferts (2009, background): “Furthermore, the instantaneous IR luminosity of a SB can vary by more than an order of magnitude (e.g. Cid Fernandes et al. 2004; Davies et al. 2007), depending on its size and age.”
Recovering galaxy star formation and metallicity histories from spectra using VESPA (2007, methodology): “Different teams have analysed a large number of galaxies in this way, whether by using the full available spectrum (Glazebrook et al. 2003; Panter, Heavens & Jimenez 2003; Cid Fernandes et al. 2004; Heavens et al. 2004; Mathis, Charlot & Brinchmann 2006; Ocvirk et al. 2006; Cid Fernandes et al. 2007”
Adaptive Optics for Astronomy (2012, background): “Stellar population synthesis of optical (Cid Fernandes et al. 2004, Sarzi et al. 2006) and infrared (Riffel et al. 2009a) data suggest that while some AGN appear to be associated with recent (< 100Myr old) starbursts, the nuclear stellar spectra of others are dominated by intermediate age or very…”
The Coevolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe (2014, methodology): “Other authors have proposed further refinements of this division (e.g. Stasinska et al. 2006, Kewley et al. 2006, Cid Fernandes et al. 2011).”
PRECISE BLACK HOLE MASSES FROM MEGAMASER DISKS: BLACK HOLE–BULGE RELATIONS AT LOW MASS (2010, background): “In NGC 3393 we both agree that the stellar populations are old; Cid Fernandes et al. find that 4% of the luminosity in this source come from stars with an age< 25 Myr.”
Semi‐empirical analysis of Sloan Digital Sky Survey galaxies – I. Spectral synthesis method (2005, methodology): “This is a common problem in population synthesis (e.g. Cid Fernandes et al. 2001; Tremonti 2003; Panter et al. 2004).”
The Evolution of the Star Formation Activity in Galaxies and Its Dependence on Environment (2005, background): “However, in the great majority of cases an AGN with an emission line spectrum is associated with some level of star formation activity (e.g. Heckman et al. 1995, Cid Fernandes et al. 2004 and references therein), therefor the contamination of the population of [OII ] emitters from passive galaxies i”
Modelling and interpreting spectral energy distributions of galaxies with BEAGLE (2016, background): “In practice, most codes designed to fit galaxy spectra (e.g. PPXF, Cappellari & Emsellem 2004; STARLIGHT, Cid Fernandes et al. 2005; STECKMAP, Ocvirk et al. 2006; ULYSS, Koleva et al. 2009) suffer from intrinsic limitations.”