Halton Arp included NGC 7625 as object 212 in hisAtlas of Peculiar Galaxies, indicating it displayed unexplained physical processes.[10] In theThird Reference Catalogue of Bright Galaxies, NGC 7625 was assigned amorphological classification of SA(rs)a pec, which indicates a peculiarspiral galaxy (SA) with a transitional ring structure (rs) and tightly woundspiral arms (a).[11] In 1981 it was designated ablue compact dwarf byT. X. Thaun and G. E. Martin on the basis of strongemission lines from ionized gas.[12] A prominent visible feature is an open ring of dust lanes with an angular radius of about15″–20″.[13]
NGC 7625 displays indications of a recentinteraction with another galaxy. Velocity measurements suggest the inner part of the galaxy is rotating in a different plane than the outer parts. The angle between these two planes increases with distance from the galactic center, reaching 50° at a radius of 6 kpc. Hence this may be apolar-ring galaxy, with the added gas accreted from thedwarfsatellite galaxy UGC 12549.[13] There is a large amount of gas and dust undergoing significantstar formation, with emission ofH-alpha concentrated at the core and in separate knots along exterior curved structures.[6]
^abDemoulin, Marie-Helene (July 1969), "Observations of Galaxies with Large amounts of Dust. I. The Galaxy NGC 7625",Astrophysical Journal,157: 69,Bibcode:1969ApJ...157...69D,doi:10.1086/150050.
^abMoiseev, A. V. (October 2008), Funes, José G.; J., S.; Corsini, Enrico Maria (eds.), "3D Spectroscopy of the Ionized Gas Kinematics in Galactic Rings",Proceedings of the conference held 1–5 October 2007 at the Centro Convegni Matteo Ricci, Rome, Italy, Formation and Evolution of Galaxy Disks ASP Conference Series, vol. 396, San Francisco: Astronomical Society of the Pacific, pp. 283–284,arXiv:0801.1550,Bibcode:2008ASPC..396..283M.
^De Vaucouleurs, Gerard; et al. (1991),Third Reference Catalogue of Bright Galaxies, 3.9,Bibcode:1991rc3..book.....D.
^Thuan, T. X.; Martin, G. E. (August 1981), "Blue compact dwarf galaxies. I. Neutral hydrogen observations of 115 galaxies",Astrophysical Journal,247:823–848,Bibcode:1981ApJ...247..823T,doi:10.1086/159094.
Srivastav, S.; et al. (October 2023), "ATLAS23urs (AT2023vyl): discovery of a candidate SN in NGC 7625 (23 Mpc)",Transient Name Server AstroNote,284: 1,Bibcode:2023TNSAN.284....1S.
Li, Jonathan G.; et al. (August 1993), "The Molecular Gas and Star Formation in IRAS Bright Early-Type Disk Galaxies. I. NGC 7625",Astrophysical Journal,413: 150,Bibcode:1993ApJ...413..150L,doi:10.1086/172984.
Yasuda, Naoki; et al. (February 1992), "CO Observations of the Peculiar Galaxy NGC 7625 and Detection of Infalling Molecular Gas",Publications of the Astronomical Society of Japan,44:1–7,Bibcode:1992PASJ...44....1Y,doi:10.1093/pasj/44.1.1.
Brosch, N.; Loinger, F. (September 1991), "Extragalactic dust. IV. NGC 7625",Astronomy and Astrophysics,249: 327,Bibcode:1991A&A...249..327B.
Lynds, B. T.; Furenlid, I. (June 1973), "Color Variations in NGC 7625",Bulletin of the American Astronomical Society,5: 349,Bibcode:1973BAAS....5..349L.
