Compact Extranuclear Structures of Mkn 298 (Poster paper)

Summary

RESULTS AND DISCUSSION

Mkn 298 is known as a morphologically peculiar system (Fig. 1), showing a chain (c, d, e) of small compact blue emitting regions (Stockton 1972) aligned on its eastern side up to ∼ 80 arcsec from the main body of the galaxy. These regions are aligned, with a tail (b) resembling a spiral arm located on the eastern side of the galaxy (a). On the western side a very faint trace of spiral arm is also visible, d and e are characterized by an emission line spectrum, while spectra of c do not show any trace of either emission or absorption (Stockton 1972; Metik and Pronik 1982).

The contour maps of the extended emission lines Hα, Hβ and [OIII]λλ4959, 5007 have been used to isolate six different emitting regions in a and b. Each strip on the 2D-spectrum has then been mashed into a ID-spectrum and the diagnostic line ratios proposed by Veilleux and Osterbrock (1987) have been plotted in the diagnostic diagrams giving [OIII]λ5007/Hβ versus [SII]λλ6716+6731/Hα, [N II]λ6583/Hα, [OI]λ6300/Hα. The effect of reddening has been evaluated from the Hα/Hβ ratio using the Whitford (1958) reddening curve as parameterized by Miller and Mat hews (1972) and adopting the intrinsic ratio 2.81.