A tilted disk and a faint companion: NGC 5775 and NGC 5774 in gravitational dialogue
This interacting galaxy pair lies about 85 million light-years away in the constellation Virgo.
On the left is NGC 5775, an edge-on SBc spiral galaxy about 100,000 light-years across, with an apparent size of 4.2 × 1.0 arcminutes. Its disk is marked by dark dust lanes and active star formation, which appears to drive galactic outflows—ionized gas rising above the plane is seen in H-alpha and X-ray observations.
To the right is NGC 5774, a low surface brightness SAB(rs)d spiral, roughly 75,000 light-years wide and 2.2 × 1.6 arcminutes in apparent size. It shows faint, patchy arms and a weak bar, with localized areas of star formation.
The two galaxies are connected by a bridge of neutral hydrogen (HI), indicating an ongoing but relatively gentle gravitational interaction. Although there are no dramatic tidal tails, this exchange of gas may be stimulating star formation in both systems—particularly in NGC 5775’s disk and halo.
Imaged in LRGB and H alpha on my Planewave CDK 1000 at Observatorio El Sauce, Chile.
Image acquisition and processing: Mike Selby