Spirals can do it, too – a spiral host in a 2 Mpc double-double lobed radio galaxy

LEDA 896325 is unique in several ways. First of all, the occurrence of giant radio lobes associated with spiral galaxies is extremely rare - such structures are usually hosted by massive, gas-poor elliptical galaxies with little star formation. J1350-1634 extends to 2 megaparsecs in linear size. To confirm the galaxy’s morphology, two modelling approaches have been applied using the Dark Energy Spectroscopic Imaging Survey data. Both models clearly show disk-like and spiral features.

Moreover, J1350-1634 is a double-double lobed radio source. Jets usually remain active for at most tens of millions of years. However, some galaxies exhibit more than one episode of jet activity, leading to a formation of multiple lobes. In J1350-1634 two pairs are visible: the north-eastern and south-western outer and inner lobes. The energy fluxes at several radio wavelengths made it possible to estimate their age: 120 and 35 million years for the outer and the north-eastern inner lobes, respectively. We need more detailed radio observations to investigate the possibility of a third activity episode.

An important property of AGNs is the presence of a supermassive central black hole. The spectral data for LEDA 896325 make it possible to study the stellar velocities in the galaxy, which indicate the black hole mass of 240 millions of solar masses. This supports the idea that large black hole mass plays a key role in jet launching mechanisms.