UGC 3697, Integral Sign Galaxy

UGC 3697
UGC 3697: Images (bands L, W) with the VLA Schmidt in Chile from years 2000 and 2017 [492]


The «Integral Sign Galaxy» (GB 1) was found in 1967 by Geoffrey Burbidge in an idle perusal of the photo plates of the «Palomar Observatory Sky Survey». No other galaxies with that unusual form of an integral sign were known at that time. [490]

Physical Properties

UGC 3697 is a low-mass, Sd spiral galaxy. It shows a super thin disk morphology, that we see edge-on. It is warped like a potato chip or a music record that was too long in the sun. Some degree of warping is observed in a large fraction of galaxies, but only few are warped as much as UGC 3697. In contrast to normal edge-on spirals, where the brightest concentration of H-I is typically found near the central regions of the galaxy, UGC 3697 shows a bright blob of emission near its western edge. Gas filaments also extend from this location, reaching up to ∼7 kpc from the plane. Neither the filaments nor the bright midplane clump have any obvious optical counterparts.

UGC 3697 is part of a small galaxy group that includes the peculiar elliptical galaxy UGC 3714 and several dwarf galaxies. UGC 3714, at a projected distance of 39 kpc from UGC 3697, is the optically brightest group member, and has long been presumed to be responsible for exciting the warp of UGC 3697 via tidal effects. However, tides are rather inefficient warp drivers. New observations have revealed strong evidence that the galaxy recently had merged with a satellite dwarf galaxy. [491]

Apparent magnitudes in different filters are: B 13.1 mag, J 11,508 mag, H 10,822 mag, K 10,528 mag. The distance is given with 46.27 Mpc. [145]

«Catalogue of Principal Galaxies (PGC)», Paturel et al. 1989 [144]
NameRA [hms]Dec [dms]mTypeDim [']Btot [mag]HRV [km/s]PA [°]
UGC 369707 11 21.3+71 50 06S3.3 x .213.3313776
UGC 371407 12 33.8+71 44 56S1.8 x 1.612.7305135
PGC 2041207 13 04.5+71 39 58.4 x .215.9

Finder Chart

The galaxy UGC 3697 is located in the constellation Camelopardalis. The best viewing time is September to March when it is highest at night.

Chart UGC 3697
Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

Visual Observation

UGC 3697, UGC 3714
UGC 3697, UGC 3714: Pencil drawing; 12.5" Ninja-Dobson f/4.5, TV-Radian 8 mm, 181x, 0.33°, D: 6.4 mag, L: ruhig Fön; Honegg 1460 m; © 26. 12. 2002, 23:15 Eduard von Bergen

320 mm aperture: Visually, no integral sign can be seen, but a narrow, elongated line. With a brightness of 14.5 mag, the galaxy is easily recognizable under dark, alpine skies. The two 6.4 mag and 7.0 mag bright stars and the prominent triangle with 11m stars are helpful for the search. The UGC 3714 with 12.7 mag indicates that you are in the right star field. A mag 14.7 star is right next to the integral sign galaxy we are looking for.

The faint galaxy PGC 20412 with 16.0 mag can be tried as an encore. Provided you have the best viewing conditions and a lens opening of more than 320 mm. [192]

12.5" Ninja-Dobson, F:4.5, TV-Radian 8 mm 181x, 0.33°
Eduard von Bergen


144Catalogue of Principal Galaxies (PGC); Paturel G., Fouque P., Bottinelli L., Gouguenheim L.; Astron. Astrophys. Suppl. Ser. 80, 299 (1989); (2021-02-18)
145SIMBAD astronomical database;
149SkySafari 6 Pro, Simulation Curriculum;
160The STScI Digitized Sky Survey;
192Deep-Sky Guide; (2020-12-25)
490«A Peculiar Galaxy that may be at a Young Evolutionary Stage» Burbidge, E. Margaret ; Burbidge, G. R. ; Shelton, J. W.; Astrophysical Journal, vol. 150, p.783, December 1967; DOI:10.1086/149381; Bibcode:2004bdmh.confE..70M
491«Clues on the Structure and Composition of Galactic Disks from Studies of 'Superthin' Spirals: the Case of UGC3697» Matthews, Lynn search by orcid ; Uson, Juan M.; Proceedings of Baryons in Dark Matter Halos. Novigrad, Croatia, 5-9 Oct 2004.; arXiv:arXiv:astro-ph/0412391; Bibcode:2004bdmh.confE..70M
492Warped Disk of Galaxy UGC 3697; (2022-02-09)