NGC 735 is a spiral galaxy of morphological type Sb located in the northern constellation of Triangulum. It was discovered by the astronomer William Herschel on 13 September 1784. The galaxy is catalogued under several designations, including UGC 1411, PGC 7275, MCG +06‑05‑058, IRAS F01537+3356, and 2MASX J01563802+3410366.
Observational data
- Equatorial coordinates (J2000): Right ascension 01 h 56 m 37.9936 s, Declination +34° 10′ 36.446″.
- Redshift (z): 0.015441, corresponding to a heliocentric radial velocity of 4629 ± 3 km s⁻¹.
- Distance: Approximately 210 ± 15 million light‑years (64.5 ± 4.5 Mpc) based on its redshift; alternative distance estimates from non‑redshift methods give 227 ± 8 million light‑years.
- Apparent visual magnitude (V): 13.3.
- Angular size: 1.8′ × 0.8′, implying a linear diameter of roughly 126 000 light‑years (38.6 kpc).
Physical characteristics
NGC 735 exhibits a moderately wound spiral structure typical of Sb galaxies. Spectroscopic observations suggest the presence of a low‑luminosity active galactic nucleus (AGN), indicating that a compact central region emits significant energy across the electromagnetic spectrum beyond that expected from stellar processes alone.
Supernovae
Three supernova events have been recorded in NGC 735:
- SN 1972L (type unspecified, magnitude 15) discovered by John Huchra on 3 September 1972.
- SN 2000dj (Type II, magnitude 17.4) discovered by the Lick Observatory Supernova Search on 8 September 2000.
- SN 2006ei (Type Ic, magnitude 18.5) discovered by the same survey on 21 August 2006.
Group membership
NGC 735 is a member of the NGC 669 galaxy group (also known as LGG 37), a loose aggregation of roughly 34 galaxies in the same region of the sky.
References
- NASA/IPAC Extragalactic Database (NED) entry for NGC 735.
- S. Asmus et al., “Local AGN survey (LASr): I. Galaxy sample, infrared colour selection, and predictions for AGN within 100 Mpc,” Monthly Notices of the Royal Astronomical Society, 2020.
- SIMBAD astronomical database, object identifier NGC 735.
- Published supernova circulars and transient name server entries for SN 1972L, SN 2000dj, and SN 2006ei.