An Unusual Radio Galaxy in Abell 428: A Large, Powerful FR I Source in a Disk‐dominated Host

Abstract

We report the discovery of a powerful (∼ 10 24 h −2 75 W Hz −1 at 20cm) FR I radio source in a highly flattened disk-dominated galaxy. Half of the radio flux from this source is concentrated within the host galaxy, with the remainder in a pair of nearly symmetrical lobes with total extent ∼ 200 kpc nearly perpendicular to the disk. The traditional wisdom maintains that powerful, extended radio sources are found only in ellipticals or recent merger events. We report B, R, J, and K imaging, optical spectroscopy, a rotation curve, an IRAS detection, and a VLA 20 cm image for this galaxy, 0313-192. The optical and near infrared images clearly show a disk. We detect apparent spiral arms in a deep B band exposure, and a dust-lane from a higher resolution B band image. The reddened nucleus is consistent with extinction by a similar dust-lane. The optical spectrum suggests a central AGN and some evidence of a starburst, with both the AGN and central starlight appearing substantially reddened (perhaps by the optical dust-lane). From analysis of the extended line emission in [OIII] and Hα, we derive a rotation curve consistent with an early-type, dusty spiral seen edge-on. From the IRAS detection at 60 and 100µm we find that the ratio of Far IR to radio flux places this object firmly as a radio galaxy (i.e. the radio emission is not powered by star formation). The radio structure suggests that the radio source in this galaxy is related to the same physical mechanisms present in jet-fed powerful radio sources, and that such powerful, extended sources can (albeit extremely rarely) occur in a disk-dominated host.

Two interesting cases of oddball AGN

“…The discovery of the spiral-host radio galaxy 0313-192 was reported in Ledlow et al (1998), Ledlow et al (2001). Here, we present new images (see also: Keel et al (2002)) from HST and Gemini, illustrating beyond doubt the spiral (Sa/Sb) nature of the host and clearly showing a warped disk.…”

Hi absorption in nearby compact radio galaxies

“…For example, J031552-190644 is known to have a spiral host galaxy (Ledlow et al 1998) and found to have Hi gas by Ledlow et al (2001) within a galactic disc. However, the WISE data indicate that this galaxy lies in the Figure 7.…”

J1649+2635: a grand-design spiral with a large double-lobed radio source

“…Table 1 gives a complete-to-date list of spiral galaxies that host large double-lobed radio sources 1 . 0313-192 was the first confirmed doublelobed radio source hosted by a spiral galaxy (Ledlow, Owen, & Keel 1998;Ledlow et al 2001;Keel et al 2006) 2 . 0313-192 is an edge-on spiral galaxy (Hubble type Sb) that hosts a 360 kpc double-lobed radio source.…”