NGC 2276 / Arp 25 / Arp 114 - Intermediate Spiral Galaxy in Cepheus

This image captures two small Arp catalog objects located about 120 million light-years away in the far-northern constellation of Cepheus. Remarkably, this is one of the very few regions of the sky where two Arp objects can be framed together in a narrow field of view. With a declination near +86°, they are also the closest major deep-sky galaxies to Polaris.

The large face-on spiral galaxy dominating the center is NGC 2276, also known as Arp 25, an intermediate spiral galaxy categorized as a “spiral galaxy with one heavy arm.” Roughly 6 arcminutes to the right lies the giant elliptical NGC 2300. Together, the pair forms Arp 114, an “elliptical galaxy close to and perturbing a spiral galaxy.” Discovered by F. A. T. Winnecke on June 26, 1876, NGC 2276 hosts vigorous star formation and the off-nuclear intermediate-mass black hole NGC 2276-3c (~50,000 solar masses). Recent work also reveals a ~100 kpc ram-pressure tail, underscoring environmental effects in the NGC 2300 group. Both galaxies are about 100,000 light-years in diameter, and their proximity in both sky position and velocity strongly suggests gravitational interaction. The bright ~8th-magnitude foreground star near the center is HD 51141. 

NGC 2276’s asymmetric structure is striking: its core is displaced well left and above the geometric center, with a single massive arm sweeping around the top, and multiple parallel arms - three or more - along the bottom. The galaxy is undergoing intense star formation, evident in numerous luminous knots and H II regions, especially along the left-hand side. Many of these clumps may be super star clusters. The primary arms exhibit Vorontsov-Velyaminov rows—straight arm segments meeting at nearly uniform angles—features whose formation remains poorly understood.

Imaging Notes:

This dataset totals only 2h30m of integration. Significant stacking artifacts around bright stars were addressed using pixel-math substitution from an ACDNR-processed version. To improve the signal-to-noise ratio, a synthetic luminance channel was created by integrating all frames. With roughly 10x more exposure, far fainter tidal features and the full extent of the disturbed spiral arms could be revealed. Even so, I hope the image conveys the dynamic asymmetry of NGC 2276 and the smooth, spheroidal form of NGC 2300 in a single, compelling frame.

Sources:

wikipedia.org

chandra.harvard.edu

www.nasa.gov

esahubble.org

Data credit: Telescope.Live