Universität zu Köln

Smajic, S., Moser, L., Eckart, A., Busch, G., Combes, F., Garcia-Burillo, S., Valencia-S, M. and Horrobin, M. (2015). The nuclear gas disk of NGC 1566 dissected by SINFONI and ALMA. Astron. Astrophys., 583. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 1432-0746

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Abstract

We present the results of near-infrared (NIR) H- and K-band European Southern Observatory SINFONI integral field spectroscopy (IFS) of the Seyfert galaxy NGC 1566. We investigate the central kpc of this nearby galaxy, concentrating on excitation conditions, morphology, and stellar content. NGC 1566 was selected from our NUGA (-south) sample and is a ringed, spiral galaxy with a stellar bar in north-south direction (PA similar to 5 degrees). The galaxy inhibits a very active Seyfert 1 nucleus but narrow line ratios from optical observations in the nuclear region are similar to Seyfert 2 galaxies. The recent strong activity phase, as inferred from strong variablity in X-ray to IR wavelengths, makes NGC 1566 an ideal candidate to look for feeding and feedback of a supermassive black hole. We present emission and absorption line measurements in the central kpc of NGC 1566. Broad and narrow Br gamma lines were detected. The detection of a broad Br gamma component is a clear sign of a supermassive black hole in the center. Blackbody emission temperatures of similar to 1000 K are indicative of a hot dust component, the torus, in the nuclear region. The molecular hydrogen lines, hydrogen recombination lines, and [Fe II] indicate that the excitation at the center is coming from an AGN. The central region is predominantly inhabited by molecular gas, dust, and an old K-M type giant stellar population. The molecular gas and stellar velocity maps both show a rotation pattern. The molecular gas velocity field shows a perturbation toward the center that is typical for bars or spiral density waves. The molecular gas species of warm H-2(1-0)S(1) and cold (CO)-C-12(3-2) gas trace a nuclear gas disk of about 3 '' in radius with a nuclear spiral reaching toward the nucleus. From the equivalent width of H-2(1-0)S(1) a molecular ring with r less than or similar to 3 '' can be inferred. This spiral seems to be an instrument that allows gas to fall toward the nucleus down to <50 pc scales. The excitation of molecular hydrogen in the nuclear gas disk is not clear, but diagnostic diagrams show a distinction between the nuclear region and a <9 Myr old star-forming region at the southwestern spiral arm. Gas that might be shocked is detected from the center, which is visible in dispersion maps of H-2(1-0)S(1) and (CO)-C-12(3-2) and in the 0.87 mm continuum.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Smajic, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Moser, L. UNSPECIFIED UNSPECIFIED UNSPECIFIED Eckart, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Busch, G. UNSPECIFIED UNSPECIFIED UNSPECIFIED Combes, F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Garcia-Burillo, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Valencia-S, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Horrobin, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-387889
DOI:	10.1051/0004-6361/201424850
Journal or Publication Title:	Astron. Astrophys.
Volume:	583
Date:	2015
Publisher:	EDP SCIENCES S A
Place of Publication:	LES ULIS CEDEX A
ISSN:	1432-0746
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language INTEGRAL FIELD SPECTROSCOPY; ACTIVE GALACTIC NUCLEI; BLACK-HOLE MASS; MOLECULAR-HYDROGEN EXCITATION; NEARBY SEYFERT-GALAXIES; AGN-DRIVEN OUTFLOW; STAR-FORMATION; FE-II; TRANSITION-PROBABILITIES; LINE EMISSION Multiple languages Astronomy & Astrophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/38788