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Title: High-resolution imaging of Brackett-gamma and H2 1-0 S(1) emission in the Seyfert galaxy NGC 1068

Journal Article · · Astrophysical Journal; (USA)
DOI:https://doi.org/10.1086/185968· OSTI ID:5912354
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  1. Max-Planck-Institut fuer Physik und Astrophysik, Garching (Germany, F.R.)

This paper reports 1-arcsec resolution imaging of 2-micron H I Br-gamma and H2 1-0 S(1) line emission toward the nucleus of the Seyfert 2 galaxy NGC 1068. The data, taken with a new imaging Fabry-Perot, show that the emission in both infrared lines originates from within 2 arcsec (170 pc) of the peak of radio, near-infrared, and visible continuum radiation. The vibrational H2 emission has a double-lobed shape, with a minimum toward the nucleus and two peaks about 1.3 arcsec on either side of the nucleus along position angle 70 deg east of north. In contrast, the Br-gamma emission is peaked on the nucleus, similar to the central radio continuum structure and the narrow-line region (NLR) in the visible. The Br-gamma emission has an about 1 arcsec (FWHM) diameter and is more compact than the distributions of visible NLR tracers. The H2 emission is probably produced in hot gas with mass a few 1000 solar masses. However, the total H2 mass in the circumnuclear region hydrogen may approach 10 to the 8th solar masses. The H2 emission is not produced in a 1-pc size obscuring torus but probably comes from a system of molecular clouds in the vicinity of the NLR. The molecular clouds probably contribute significantly to the extinction of the nuclear source. It is proposed that the circumnuclear Br-gamma and H2 emission lines are excited in gas heated by UV or X-ray photons emitted by a central nonstellar source. 35 refs.

OSTI ID:
5912354
Journal Information:
Astrophysical Journal; (USA), Vol. 370; ISSN 0004-637X
Country of Publication:
United States
Language:
English