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Next: Strongly Interacting Galaxies Up: The Group of Nearby Previous: NGC 7552

NGC 7582

is a barred spiral which is interacting with several bright neighbours, namely NGC 7590, NGC 7599 (see Fig. 12), and most likely also NGC 7552 (see above). Recent ATCA measurements reveal several HI bridges between the group members (B. Koribalski et al., in prep.). NGC 7582 has a Seyfert2 nucleus, but it is clearly dominated by starburst activity as shown by strong radio emission, which probably originates from many supernova remnants, and by the presence of numerous HII regions

Figure: HI distribution (contours) of NGC 7582 and two nearby galaxies, NGC 7590 ($v_{\rm sys}$ = 1596 kms-1) and NGC 7599 ($v_{\rm sys}$ = 1654 kms-1) overlaid onto the optical emission (greyscale) from the Digitized Sky Survey (DSS). The contour levels are 0.15, 0.3, 0.6, 1.2, 2.25, and 4.5 Jybeam-1 kms-1. Please note that no primary beam correction has been applied here. Several tidal tails are visible near NGC 7582, pointing toward the neighbours in the east and toward NGC 7552 which lies at a projected distance of $\sim$30. These data have been obtained with the 375-m array of the ATCA (12 h). The angular resolution is about $1\farcm7 \times 1\farcm3$.
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\plotfiddle{NGC7582_GROUP_OVER.PS}{13.4cm}{-90}{53}{53}{-210}{+280}
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(Morris et al. 1985). TAURUS Fabry-Perot observations of the circum-nuclear H$\alpha$ emission suggest a fast-rotating disk of HII regions (diameter $\sim$1 kpc) in the plane of the galaxy. Morris et al. also suggest that blue-shifted OIII line emission originates from high excitation gas expanding outwards from the nucleus in a cone. The HI distribution of NGC 7582 (see Fig. 13) is rather asymmetric (because of tidal interaction) and extends over a velocity range of at least 400 kms-1. The absorption lines cover nearly the same range, but are $\sim$50 kms-1 blue-shifted with respect to the emission. We find the HI absorption line clearly shifting over the face of the continuum emission indicating a fast-rotating ring. Circumnuclear H$\alpha$ emission, suggesting a similar feature (see above), hints at a mixture of gas phases in the nuclear region.

Figure: HI distribution and mean velocity field of NGC 7582. These data were taken with the 1.5-km array of the ATCA. The angular resolution is $38\arcsec \times 23\arcsec$.
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\plottwo{NGC7582_HI.PS}{NGC7582_VEL.PS}
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Recent high-resolution 8.64-GHz observations with the ATCA by Norris & Forbes (1996) suggest a double nucleus.


next up previous
Next: Strongly Interacting Galaxies Up: The Group of Nearby Previous: NGC 7552
Baerbel Koribalski
2002-04-03