MBG 02223 – 1922: a newly identified luminous Seyfert galaxy

• Published in: Monthly notices of the Royal Astronomical Society 1993-03, Vol.261 (1), p.170-174
• Main Authors: Coziol, Roger, Peña, Miriam, Demers, Serge, Torres-Peimbert, Silvia
• Format: Article
• Language: English
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; galaxies: individual: MBG 02223 – 1922; galaxies: photometry; galaxies: Seyfert; Quasars. Active or peculiar galaxies, objects, and systems; Stellar systems. Galactic and extragalactic objects and systems. The universe
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/261.1.170

In the context of the Montreal Blue Galaxy (MBG) survey, we report the identification of MBG 02223 – 1922 as a new, bright (V = 13.5), Seyfert 1 galaxy. With an absolute magnitude MB = – 21.8, this galaxy is among the most luminous 10 per cent of Seyfert 1 galaxies known. In this article we present spectrophotometry in the 4300–5300 and 5800–6800 Å ranges and direct imaging in B, V and I. Analysis of the optical spectra reveals unusually broad and composite forbidden lines, suggesting a more complex dynamical structure of the narrow-line region than is usually proposed for Seyfert galaxies. The emission region is extended, with dimension 1.3 kpc. The host galaxy, a late-type spiral, is experiencing a phase of active stellar formation near the nucleus ( ~ 3 kpc from the centre). Fluxes from the nucleus, from the far-infrared to the optical, follow a well-determined power law representing a relatively flat spectrum (index α = – 1.34), typical of UV-excess Seyfert 1 galaxies and QSOs. The moderately large infrared luminosity, LIR = 6.3 × 1010 Lʘ the relatively flat far-infrared spectrum [indices α(12, 25) = – 0.98 and α(12, 60) = – 1.33], along with the average value of the flux ratio, log[F (60 µm)/F (λ5007)] = 2.5, and internal reddening, E(B – V) = 0.38, suggest that only a small quantity of dust is present in the nucleus. The different properties of this object seem to indicate a nature intermediate between the two main types of Seyfert galaxy. MBG 02223 – 1922 is probably a good example of a so-called Seyfert 1.8.