The first 62 AGNs observed with SDSS-IV MaNGA – I. Their characterization and definition of a control sample

Abstract

We report the characterization of the first 62 MaNGA Active Galactic Nuclei (AGN) hosts in the Fifth Product Launch (MPL-5) and the definition of a control sample of non-active galaxies. This control sample -comprising two galaxies for each AGNwas selected in order to match the AGN hosts in terms of stellar mass, redshift, visual morphology and inclination. The stellar masses are in the range 9.4 < log (M/M ) < 11.5, and most objects have redshifts ≤ 0.08. The AGN sample is mostly comprised of low-luminosity AGN, with only 17 nuclei with L([OIII]λ 5007) ≥ 3.8 × 10 40 erg s −1 (that we call "strong AGN"). The stellar population of the control sample galaxies within the inner 1-3 kpc is dominated by the old (∼ 4 -13 Gyr) age component, with a small contribution of intermediate age (∼640-940 Myr) and young stars (≤ 40 Myr) to the total light at 5700Å. While the weaker AGN show a similar age distribution to that of the control galaxies, the strong AGN show an increased contribution of younger stars and a decreased contribution of older stars. Examining the relationship between the AGN stellar population properties and L([OIII]), we find that with increasing L([OIII]), the AGN exhibit a decreasing contribution from the oldest (>4 Gyr) stellar population relative to control galaxies, but have an increasing contribution from the younger components with ages ∼40 Myr. We also find a correlation of the mean age differences (AGN -control) with L([OIII]), in the sense that more luminous AGN are younger than the control objects, while the low-luminosity AGN seem to be older. These results support a connection between the growth of the galaxy bulge via formation of new stars and the growth of the Supermassive Black Hole via matter accretion in the AGN phase.

Ionized gas outflow signatures in SDSS-IV MaNGA active galactic nuclei

“…We note that this AGN selection is different to the ones used in Rembold et al (2017) or Sanchez et al (2017) who both present results on AGN in MaNGA. The main difference in the sample selection is that both of these works only use the photoionisation signatures in the central region of the galaxies to classify a galaxy as an AGN candidate.…”

“…The aim of this work is to compare the kinematic characteristics of the [OIII] emission line for MaNGA-selected AGN and non-AGN in the MaNGA sample. In optical surveys, emission line flux ratios and diagnostic diagrams are the most common way to identify AGN (Baldwin et al 1981;Osterbrock 1989;Zakamska et al 2003;Kauffmann et al 2003;Kewley et al 2006;Reyes et al 2008;Yuan et al 2016). But a major caveat of large optical spectroscopic surveys such as the Sloan Digital Sky Survey (prior to MaNGA) is the small size of the optical fibres which, at 3 diameter (in the case of SDSS-I to SDSS-III surveys), only cover a fraction of the footprint of a galaxy and are only sensitive to processes close to the galactic center.…”

“…The main difference in the sample selection is that both of these works only use the photoionisation signatures in the central region of the galaxies to classify a galaxy as an AGN candidate. Rembold et al (2017) uses the SDSS-III spectroscopic data from DR12 based on the 3 single-fibre measurements whereas Sanchez et al (2017) uses the MaNGA spectroscopic information in the central 3 × 3 region analysed and measured with the PIPE3D pipeline (Sánchez et al 2016). Their AGN samples contain 62 and 98 AGN candidates, respectively.…”

“…MaNGA also allows to take full advantage of the spatial dimension of AGN ionisation signatures (Penny et al 2017;Rembold et al 2017;Sanchez et al 2017;Wylezalek et al 2017. have recently developed spatially resolved techniques tailored to the MaNGA data for identifying signatures of AGN.…”

Galaxies hosting an active galactic nucleus: a view from the CALIFA survey

“…Four recent studies using the same MPL-5 sample identify 62 AGN hosts using the SDSS-III DR12 (Alam et al 2015) integrated nuclear spectra, that comprises the central 3 × 3 region of the select galaxies. Rembold et al (2017) presents the sample and a study of the nuclear stellar populations with starlight (Cid Fernandes et al 2005). Their classification is based on the BPT diagram togheter with the WHAN diagram, i.e., less restrictive regarding the hardness of the ionization field (they do not use [S ii]/Hα and [O i]/Hα ratios in the classification scheme).…”