|S178||Alpha||FR||Class||ID||Spectrum||Best z||mag.||LAS||lg P178||D|
|16.7||0.66||II||HP+HB||Gal||0.2769||V = 18.5*||9.09||26.30||31.7|
|Size:||11.5 × 11.5 arcsec²|
|Credits:||Leahy (1997), R. A. Laing (priv comm)|
The northern hotspot is almost in the centre of its lobe, making it one of the most "recessed" hotspots in the Atlas sample. In the southern lobe, as well as the prominent hotspot at the tip, there is a low-contrast compact feature near the northeastern (inner) edge of the lobe, visible here as a yellowish peak. This feature is more prominent in a 6-cm image (R. A. Laing, priv. comm.), i.e. its spectrum is flatter than the surrounding lobe.
The small red cross gives the position of the identification and its size gives the nominal uncertainty; but there may be a larger systematic uncertainty in aligning the radio and optical coordinate systems. The faint peak just north of the cross is the most likely candidate for a radio core. An alternative possibility is the very faint (0.5 mJy) peak in the centre of the "gap" between the two lobes, about 0.5 arcsec from the nominal optical position. Neither of these components has a particularly flat spectrum.
The other compact features between the lobes suggest there is at least one jet. If the core is the component nearest the optical position, the jet is one-sided, consisting of three faint knots and directed towards the northern hotspot. The other interpretation would give a two-sided jet with the northern hotspot symmetric across the core from the compact feature in the southern lobe.
McCarthy, Spinrad & van Breugel
H alpha +[N II] emission along the radio axis, suggesting that the
peculiar structure of the northern lobe may be caused by a jet-cloud
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