NGC 6052 is a pair of interacting galaxies located in the constellation Ursa Major. It is listed as entry 6052 in the New General Catalogue (NGC) and is also catalogued as Arp 209 in Halton Arp’s Atlas of Peculiar Galaxies. Other identifiers include PGC 57111 and IRAS 16170+3016.
Discovery
The system was discovered by William Herschel on 13 April 1790 using a reflecting telescope. Herschel recorded it as a faint nebular object; later observations resolved it into a pair of colliding galaxies.
Morphology and Classification
NGC 6052 consists of two galaxies in the process of merging, exhibiting tidal tails and disturbed structure typical of interacting systems. In the de Vaucouleurs morphological classification it is often described as a peculiar, star‑bursting system (e.g., “SB(s)bc pec”). The interaction has triggered extensive regions of active star formation, making the pair an infrared‑bright source.
Distance and Redshift
Spectroscopic measurements give a heliocentric radial velocity of approximately 4 400 km s⁻¹, corresponding to a redshift (z) of about 0.0146. Assuming a standard ΛCDM cosmology (H₀ ≈ 70 km s⁻¹ Mpc⁻¹), this places NGC 6052 at a luminosity distance of roughly 200–250 million light‑years (≈ 60–80 Mpc). Published distance estimates vary within this range.
Physical Characteristics
| Property | Value |
|---|---|
| Right Ascension (J2000) | 16ʰ 20ᵐ 47.9ˢ |
| Declination (J2000) | +30° 14′ 58″ |
| Apparent magnitude (V) | ≈ 13.2 |
| Angular size | ≈ 1.4 × 0.9 arcmin |
| Radial velocity | ~4 400 km s⁻¹ |
| Distance | ~200–250 Mly (≈ 60–80 Mpc) |
| Alternative names | Arp 209, PGC 57111, IRAS 16170+3016 |
The collision has produced bright knots of young, massive stars and numerous H II regions, which dominate the ultraviolet and infrared output. NGC 6052 is therefore classified as a luminous infrared galaxy (LIRG).
Observational History
Following Herschel’s discovery, the system was photographed photographically in the 19th century and later imaged with modern space‑based observatories. The Hubble Space Telescope has resolved individual star clusters within the interacting pair, providing insight into the triggered star‑formation processes.
Scientific Significance
NGC 6052 serves as a nearby laboratory for studying galaxy interaction dynamics, starburst activity, and the morphological transformation of galaxies during mergers. Its inclusion in the Arp catalog highlights its status as a prototypical example of a colliding galaxy pair with prominent tidal features.
References
- Arp, H. (1966). Atlas of Peculiar Galaxies. California Institute of Technology.
- de Vaucouleurs, G., de Vaucouleurs, A., Corwin, H. G., et al. (1991). Third Reference Catalogue of Bright Galaxies (RC3). Springer.
- NASA/IPAC Extragalactic Database (NED), results for NGC 6052.
- Hubble Space Telescope imaging (various programs, public archive).
