Study of the close environment of the active nucleus in NGC 1068 by decomposition of forbidden O III and H-beta emission-line profiles

Details Study of the close environment of the active nucleus in NGC 1068 by decomposition of forbidden O III and H-beta emission-line profiles Study of the close environment of the active nucleus in NGC 1068 by decomposition of forbidden O III and H-beta emission-line profiles

Dec 1983

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1983apj...275..493a&link_type=abstract

Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 275, Dec. 15, 1983, p. 493-510.

Other

53

Galactic Nuclei, H Beta Line, Oxygen Spectra, Emission Spectra, Forbidden Transitions, Galactic Radiation

Scientific paper

We analyze and discuss in this paper the [O III] λλ4959, 5007 and Hβ emission-line profiles observed in various positions over the central region in NGC 1068. The profiles change drastically over a spacing of 1".2. We have performed a quantitative decomposition of these profiles using Gaussian individual components and find a clear separation of the following systems:
i) A narrow feature (FWHM ∼100 km s-1) seen both along position angle PA = 55° and 145°. This component follows the stellar rotation observed in PA = 55°, while it appears to have large radial motions in PA =145°. It shows up more strongly along PA = 55°, which is also the position of the major axis corresponding to the inner spiral arm structure observed in this galaxy. The value of its line intensity ratio I([O III] λλ4959 + 5007)/I(Hβ) = 8 is compatible with a classical ionization by hot stars, although not uniquely. We interpret this feature as the line emission from ionized regions in the inner disk of the galaxy. Along the minor axis, the overall emission from this component is weaker and corresponds to gas in a lower stage of ionization.
ii) A narrow feature (FWHM ∼100 km s-1) detected in the NE quadrant. Dynamically this is clearly separated from the disk narrow feature along PA = 55°, while the value here found for the line intensity ratio, I([O III])/I(Hβ) = 17, implies ionization by nonstellar radiation. We attribute this feature to a nebulosity seen in projection in the NE quadrant, but most probably situated out of the plane of the disk and directly photoionized by the synchrotron emission from the active nucleus in NGC 1068.
iii) A broad (FWHM = 1670 km s-1), blueshifted component (Vɛ - Vsystemic = -210 km s-1) is found in both the [O III] and the Hβ line profiles. From the present results this feature seems to be slightly extended (about 240 pc in radius) rather than being confined to the center, suggesting that the broadening is due to a widely distributed collection of cloudlets or filaments and not to an organized motion such as that of a rotating disk, which could not be so large.
iv) A characteristic of the individual clouds detected in the central region of NGC 1068 is that the blueshifted ones are also the more central, as is seen in other objects.

Affiliated with

Also associated with

No associations

Rating

Study of the close environment of the active nucleus in NGC 1068 by decomposition of forbidden O III and H-beta emission-line profiles does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Study of the close environment of the active nucleus in NGC 1068 by decomposition of forbidden O III and H-beta emission-line profiles, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Study of the close environment of the active nucleus in NGC 1068 by decomposition of forbidden O III and H-beta emission-line profiles will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1802610