NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-05-22 T06:16:41 PDT
Help | Comment | NED Home

For refcode 2004MNRAS.355..273C:
Retrieve 79 NED objects in this reference.
Please click here for ADS abstract

NED Abstract

Copyright by Royal Astronomical Society. 2004MNRAS.355..273C The star formation history of Seyfert 2 nuclei Cid Fernandes, R.; Gu, Q.; Melnick, J.; Terlevich, E.; Terlevich, R.; Kunth, D.; Rodrigues Lacerda, R.; Joguet, B. Abstract. 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 Ainterval. 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 Hbeta 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 non-stellar 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. Keywords: galaxies: active, galaxies: Seyfert, galaxies: statistics, galaxies: stellar content
Retrieve 79 NED objects in this reference.
Please click here for ADS abstract

Back to NED Home