J1649+2635: A Grand-Design Spiral with a Large Double-Lobed Radio Source

TL;DR

This paper reports the discovery of a rare grand-design spiral galaxy with an extensive double-lobed radio source, highlighting its unique features and environment, and discussing possible origins of its radio emission.

Contribution

It presents the first detailed study of J1649+2635, a spiral galaxy with a large double-lobed radio source and an extensive optical halo, suggesting a new class of radio-loud spiral galaxies.

Findings

J1649+2635 hosts a 100 kpc double-lobed radio source.

The galaxy has a significant optical halo and resides in an overdense environment.

The black hole mass is estimated at 3-7 x 10^8 solar masses.

Abstract

We report the discovery of a grand-design spiral galaxy associated with a double-lobed radio source. J1649+2635 (z = 0.0545) is a red spiral galaxy with a prominent bulge that it is associated with a L$_{1.4{\rm GHz}}\sim$10$^{24}$WHz$^{-1}$ double-lobed radio source that spans almost 100kpc. J1649+2635 has a black hole mass of M$_{\rm BH} \sim$ 3--7 $\times$ 10$^8$M$_{\odot}$ and SFR$\sim$ 0.26 -- 2.6M$_{\odot}$year$^{-1}$. The galaxy hosts a $\sim$96kpc diffuse optical halo, which is unprecedented for spiral galaxies. We find that J1649+2635 resides in an overdense environment with a mass of M$_{dyn} = 7.7^{+7.9}_{-4.3} \times 10^{13}$M$_{\odot}$, likely a galaxy group below the detection threshold of the ROSAT All-Sky Survey. We suggest one possible scenario for the association of double-lobed radio emission from J1649+2635 is that the source may be similar to a Seyfert galaxy, located in a denser-than-normal environment. The study of spiral galaxies that host large-scale radio emission is important because although rare in the local Universe, these sources may be more common at high-redshifts.