A dust-laden bar feeding a spiral pattern twisted by the galaxy’s own internal dynamics
NGC 613 is a barred spiral galaxy of type SB(rs)bc in the constellation Sculptor, located about 67 million light-years away.
It spans roughly 100,000 light-years, with an apparent size of about 5.4 × 3.1 arcminutes. The strong central bar contains asymmetric, offset dust lanes that curve inward at different angles, tracing gas inflow toward a luminous nucleus. At the bar ends, the tightly wrapped inner arms form a partial (rs) pseudoring, while the inner spiral pattern shows a pronounced S-shaped twist.
These distortions are driven not by an external interaction but by the bar itself, whose gravitational torque forces gas and stars onto non-circular orbits, producing shocks, inflow, and the characteristic asymmetry across the inner disk. The outer arms continue this imbalance, with one side more tightly filamentary and the opposite arm flaring outward more diffusely, a mild m=1 mode common in strongly barred systems.
There are H alpha regions around the nucleus and in throughout parts of the arms indicating active star forming regions.
A smooth, faint halo surrounds the disk, and the field contains numerous background galaxies, including edge-on spirals, blue compact sources, and faint spheroidals scattered across the frame.
Imaged in LRGB and H alpha on my Planewave CDK 1000 at Observatorio El Sauce, Chile.
Image acquisition and processing: Mike Selby