Ordered structure, violent transformation, and a deceptive alignment in one southern galaxy field
This field is centered on IC 2150, a barred spiral galaxy of type SB(r:)bc in the constellation Columba. IC 2150 lies about 143 million light-years (≈ 44 Mpc) away and spans roughly 2.6′ × 0.8′, corresponding to a diameter of about ~115,000 light-years. Its structure shows a clear inner bar and ring feeding outward into layered spiral arms, with distinct star-forming knots along the arms and subtle outer asymmetry hinting that even apparently well-structured spirals rarely have entirely uneventful histories.
Just below it is PGC 17999, a compact blue irregular galaxy about ~0.8′ × 0.5′ in apparent size. Its strong blue color and clumpy light distribution suggest active star formation and a dynamically disturbed evolutionary state.
On the centre-left sits PGC 610399, roughly ~0.9′ × 0.6′, and this system is unmistakably genuinely disturbed and merging. Its asymmetric, chaotic morphology and faint suggestions of tidal debris are characteristic of a galaxy being physically reshaped by gravitational interaction.
Toward the upper left is PGC 611281, an inclined spiral about ~1.0′ × 0.6′. A faint galaxy lies close to it in projection, visually mimicking another interacting pair. However, the disk of PGC 611281 remains smooth and symmetric with no tidal tails, warping, or luminous bridges, making this far more consistent with a chance line-of-sight alignment rather than a true merger, though catalog distance comparison would confirm that definitively.
The surrounding field contains numerous faint background systems as well, turning this region into a compact gallery of galaxy evolution — structured spiral dynamics, blue irregular star formation, active gravitational disruption, and alignment-driven illusion all sharing the same scene.
Imaged in LRGB on my Planewave CDK 1000 at Observatorio El Sauce, Chile.
Image acquisition and processing: Mike Selby