Universität zu Köln

Israel, F. P., Guesten, R., Meijerink, R., Requena-Torres, M. A. and Stutzki, J. (2017). The outflow of gas from the Centaurus A circumnuclear disk Atomic spectral line maps from Herschel/PACS and APEX. Astron. Astrophys., 599. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 1432-0746

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Abstract

The physical state of the gas in the central 500 pc of NGC 5128 (the radio galaxy Centaurus A), was investigated using the finestructure lines of carbon [C I], [C II]; oxygen [O I], [O III], and nitrogen [N II], [N III] as well as the 12CO(4 3) molecular line. The circumnuclear disk (CND) is traced by emission from dust and the neutral gas ([C I] and 12CO). A gas outflow with a line-of-sight velocity of 60 km s(-1) is evident in both lines. The [C I] emission from the CND is unusually strong with respect to that from CO. The center of the CND (R < 90 pc) is bright in [O I], [O III], and [C II]; [O I] lambda 63 mu m emission dominates that of [C II] even though it is absorbed with optical depths tau = 1.0-1.5. The outflow is well- traced by the [N II] and [N III] lines and also seen in the [C II] and [O III] lines that peak in the center. Ionized gas densities are highest in the CND (about 100 cm 3) and low everywhere else. Neutral gas densities range from 4000 cm 3 (outflow, extended thin disk ETD) to 20 000 cm 3 (CND). The CND radiation field (Go approximate to 4) is weak compared to the ETD starburst field (Go approximate to 40). The outflow has a much stronger radiation field (Go = 130). The total mass of all the CND gas is 9 .1 +/- 0.9 x10(7) M-circle dot but the mass of the outflowing gas is only 15-30% of that. The outflow most likely originates from the shock-dominated CND cavity surrounding the central black hole. With a factor of three uncertainty, the mass outflow rate is approximate to 2 M-circle dot yr 1, a thousand times higher than the accretion rate of the black hole. Without replenishment, the CND will be depleted in 15-120million years. However, the outflow velocity is well below the escape velocity.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Israel, F. P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Guesten, R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Meijerink, R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Requena-Torres, M. A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Stutzki, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-237928
DOI:	10.1051/0004-6361/201629396
Journal or Publication Title:	Astron. Astrophys.
Volume:	599
Date:	2017
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 ACTIVE GALACTIC NUCLEI; MOLECULAR GAS; NGC 5128; HETERODYNE INSTRUMENT; MIDINFRARED EMISSION; STAR-FORMATION; AGN FEEDBACK; SPECTROSCOPY; RADIO; FACILITY Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/23792