Images, Maps, Spectra and SEDs

PKS0131-36

Optical spectrum taken with ESO telescopes.

Tadhunter et al. (1993)

0.030

01 33 57.7

-36 29 36

WLRG

FRI/FRII

NGC612

N

E

N

E

Notes

    This nearby source is one of the few powerful radio galaxies to be unambiguously classified as an S0 galaxy based on its optical morphology which comprises a luminous edge on disk (Emonts et al. 2008), a dust lane, a prominent stellar bulge, extended emission lines, and a radio structure which VLA observations show to be FRII-like. Close to the FRI/FRII borderline in terms of its radio luminosity, its radio morphology shows correspondingly hybrid characteristics. It has a weak core and a bright hotspot in the eastern lobe. There is evidence of a knotty jet leading to the eastern hotspot, and the western lobe is much more diffuse (Morganti et al. 1993). As discussed in detail in Emonts et al. (2008a), the dust lane associated with the optical disc of this galaxy is warped, and there are signs of faint shell structures in its outer envelope, suggestive of a past galaxy interaction. In this context it is notable that 21-cm radio observations reveal an extended H I gas structure (D > 160 kpc), that appears to connect NGC 612 with two faint companion galaxies; they also reveal that NGC 612 is connected by an H I bridge to a gas-rich companion galaxy ∼400 kpc to the east (NGC 619), the latter galaxy has an H I halo that is even more extended than that around NGC 612.

    Weak [OIII]λλ5007, 4959 and [OII]λ3727 emission lines have been detected have been detected in the optical spectrum of this object. The continuum colour looks to be typical of early-type galaxies, although the absorption features of CA II H & K, Hβ and NaID are unusually strong and narrow, and the 4000 A break appears to be weaker than average. The unusual absorption spectrum may be related to the disc structure of the host galaxy, with the possibility of absorption by the interstellar medium in the disc (Tadhunter et al. 1993)

    In terms of star formation activity, the spectral synthesis modelling results of Holt et al. (2007) reveal young stellar populations of age <0.2 Gyr throughout the disc and bulge regions at NGC 612, and at MFIR wavelengths the source has a higher (LIRG-like) luminosity that other SO galaxies of similar absolute brightness, suggesting a relatively high degree of ongoing star formation activity.

UK Schmidt image, λ4680A, width 2 arcmins.

    5 GHz VLA radio map