Variability of Markarian 1018: Seyfert 1.9 to Seyfert 1
Abstract
Simultaneous IUE and optical spectrophotometry of the Seyfert 1.9 galaxy Markarian 1018 is presented. The strength of H-beta(broad) has increased by a factor of 6.6 in 4 yr, and the galaxy now shows strong broad UV and optical line emission similar to that seen in normal Seyfert 1 galaxies, but with markedly asymmetric line profiles. As in other variable Seyfert galaxies, H-alpha emission has also increased but by a lesser amount than H-beta. Furthermore, Ly-alpha (not observed during the first epoch) is now quite strong relative to H-beta and H-alpha. Inspection of the line profiles reveals nearly identical blue asymmetric line profiles in all permitted lines; these show evidence of significant profile evolution over a 1 yr time scale. The present line ratios and the nature of their variability suggest that the enhancement in the broad-line emission is not caused by the removal of obscuring dust but by the 'lighting up' of the broad-line region.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 1986
- DOI:
- 10.1086/164758
- Bibcode:
- 1986ApJ...311..135C
- Keywords:
-
- Seyfert Galaxies;
- Spectrophotometry;
- Ultraviolet Astronomy;
- Computational Astrophysics;
- H Alpha Line;
- H Beta Line;
- Iue;
- Line Spectra;
- Ultraviolet Spectra;
- Astrophysics;
- GALAXIES: INDIVIDUAL NAME: MARKARIAN 1018;
- GALAXIES: SEYFERT;
- SPECTROPHOTOMETRY;
- ULTRAVIOLET: SPECTRA