Bibcode
Martins, L.; Mason, R. E.; Ramos Almeida, C.; Rodríguez-Ardila, A.; Riffel, R. A.; Riffel, R.; Lira, P.; González Martín, O.; Dametto, N. Z.; Flohic, H.; Ho, L. C.; Ruschel-Dutra, D.; Thanjavur, K.; Colina, L.; McDermid, R. M.; Perlman, E.; Winge, C.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 465, Issue 1, p.906-925
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2
2017
Citations
15
Refereed citations
14
Description
We present Gemini/GNIRS (Gemini Near-Infrared Spectrograph) spectroscopy
of the Seyfert 2 galaxy NGC 4388, with simultaneous coverage from 0.85
to 2.5 μm. Several spatially extended emission lines are detected for
the first time, both in the obscured and unobscured portion of the
optical narrow-line region (NLR), allowing us to assess the combined
effects of the central continuum source, outflowing gas and shocks
generated by the radio jet on the central 280 pc gas. The H I and [Fe
II] lines allow us to map the extinction affecting the NLR. We found
that the nuclear region is heavily obscured, with E(B - V) ˜ 1.9
mag. To the NE of the nucleus and up to ˜150 pc, the extinction
remains large, ˜1 mag or larger, consistent with the system of
dust lanes seen in optical imaging. We derived position-velocity
diagrams for the most prominent lines as well as for the stellar
component. Only the molecular gas and the stellar component display a
well-organized pattern consistent with disc rotation. Other emission
lines are kinematically perturbed or show little evidence of rotation.
Extended high-ionization emission of sulphur, silicon and calcium is
observed to distances of at least 200 pc both NE and SW of the nucleus.
We compared flux ratios between these lines with photoionization models
and conclude that radiation from the central source alone cannot explain
the observed high-ionization spectrum. Shocks between the radio jet and
the ambient gas are very likely an additional source of excitation. We
conclude that NGC 4388 is a prime laboratory to study the interplay
between all these mechanisms.
Related projects
Nuclear Activity in Galaxies: a 3D Perspective from the Nucleus to the Outskirts
This project consists of two main research lines. First, the study of quasar-driven outflows in luminous and nearby obscured active galactic nuclei (AGN) and the impact that they have on their massive host galaxies (AGN feedback). To do so, we have obtained Gran Telescopio CANARIAS (GTC) infrared and optical observations with the instruments
Cristina
Ramos Almeida