Largest Spiral host DDRG

Key highlights

We report the serendipitous discovery of a 2.24 Mpc double-double radio galaxy (DDRG) hosted by a spiral galaxy, marking it as the third known spiral-host DDRG — and the largest to date. The previous two were discovered by Indian pioneers in this field: Speca  (1.4 Mpc) – Prof. Ananda Hota and J2345−0449 (1.6 Mpc) – Prof. Joydeep Bagchi.

Our radio and optical analysis confirms:

• A spiral-arm feature revealed through DESI Legacy Survey DR 10 and GALFIT modelling.

• Recurrent AGN jet activity in a disk galaxy (two distinct pairs of radio lobes: outer and inner).

• Detection of radio core at VLBI scales (<10 parsec resolution).

This discovery challenges the traditional view that such giant, episodic radio galaxies are found only in ellipticals. These spiral-hosted DDRGs and GRGs do stand out, and they should be considered different from typical RGs and jetted Seyfert galaxies.

🔗 Read the full paper: https://www.aanda.org/articles/aa/full_html/2025/07/aa54987-25/aa54987-25.html