List of galaxies by surface brightness

This is a list of galaxies sorted by surface brightness. Surface brightness is a measure of how bright a diffuse object like a galaxy or nebula appears over its extended surface. The brightness over the entire galaxy is called apparent magnitude.

Malin 1 is a low surface brightness galaxy with a faint blue spiral structure.

Table

The surface brightness is calculated via ${\displaystyle S=m+2.5\log _{10}A}$. Where ${\displaystyle S}$ is surface brightness, ${\displaystyle m}$ is total magnitude, and ${\displaystyle A}$ is the total area in square arcseconds. Area is calculated using the formula for an ellipse; ${\displaystyle \pi ab}$, where ${\displaystyle a}$ is the semi-major axis and ${\displaystyle b}$ is the semi-minor axis. Each axis is half of the dimension, because each dimension is the entire length/height but the axis is only the length/height to the centre, this combined with the symmetry of an ellipse means that half the dimension is the axis.

Combining this with the original formula we get: ${\displaystyle S=m+2.5\log _{10}(\pi {\frac {a}{2}}{\frac {b}{2}})}$, which simplifies to ${\displaystyle S=m+2.5\log _{10}{\frac {\pi ab}{4}}}$.

Galaxy	Image	Surface Brightness(mag/arcsecond2)	Apparent Magnitude	Dimensions	Distance(Mly)	Type	Notes	Citations
Messier 82		20.91	8.4	9x4 arcminutes(540x240 arcseconds)	12	Spiral	Has rapid star formation due to interactions with M81 making red streaks.	[1] [2]
Messier 32		20.93	8.1	8x6 arcminutes(480x360 arcseconds)	2.5	Elliptical	Satellite galaxy of the Andromeda Galaxy	[3] [4]
NGC 3632		21.17	10.6	3x2 arcminutes(180x120 arcseconds)	70	Spiral		[5] [6]
Messier 81		21.33	6.9	21x10 arcminutes(1260x600 arcseconds)	11.6	Spiral	Faintest galaxy visible to the naked eye, despite the naked eye limiting magnitude of a star being fainter, surface brightness limits this for galaxies. [7]	[8] [9]
Whirlpool Galaxy		21.74	8.4	11x7 arcminutes(660x420 arcseconds)	31	Spiral	Has a nearby galaxy in a merger. [10]	[11] [12]
Messier 58		21.91	9.8	5.5x4.5 arcminutes(330x270 arcseconds)	62	Spiral		[13] [14]
Andromeda Galaxy		22.19	3.44	178x63 arcminutes(10680x3780 arcseconds)	2.54	Spiral/ring	Its core is significantly brighter than it's outer disk. [15]	[16] [17] [18]
Messier 87		22.45	9.6	7 arcminutes(138544.23 square arcseconds)	54	Elliptical	Roughly round, so ${\displaystyle \pi r^{2}}$ is used along with angular diameter.	[19] [20]
Messier 49		22.6	9.4	9x7.5 arcminutes(540x450 arcseconds)	60	Elliptical		[21] [22]
Triangulum Galaxy		23	5.7	70.8x41.7 arcminutes(4248x2502 arcseconds)	3	Spiral		[23] [24]

References

1. "Messier 82 (The Cigar Galaxy) - NASA Science". 2017-10-19. Retrieved 2025-12-03.
2. "Messier 82 - M82 - Cigar Galaxy". astropixels.com. Retrieved 2025-12-03.
3. "Messier 32 - NASA Science". 2017-10-19. Retrieved 2025-12-03.
4. "Messier 32 - M32". astropixels.com. Retrieved 2025-12-03.
5. "Caldwell 40 - NASA Science". 2020-08-19. Retrieved 2025-11-15.
6. "NGC 3626 (Caldwell 40)". www.skyledge.net. Retrieved 2025-11-15.
7. "M81 Naked EYE?????". Cloudy Nights. 2007-04-20. Retrieved 2025-11-15.
8. "Messier 81 - NASA Science". 2017-10-19. Retrieved 2025-11-15.
9. "M81 and M82 - Bode and Cigar Galaxies". astropixels.com. Retrieved 2025-11-15.
10. "In Colliding Galaxies, a Pipsqueak Shines Bright". NASA Jet Propulsion Laboratory (JPL). Archived from the original on 2025-10-17. Retrieved 2025-12-15.
11. "Messier 51 (The Whirlpool Galaxy) - NASA Science". 2017-10-19. Retrieved 2025-12-15.
12. "Messier 51 - M51 - Whirlpool Galaxy". astropixels.com. Retrieved 2025-12-15.
13. "Messier 58 - NASA Science". 2018-03-16. Retrieved 2025-12-15.
14. "Messier 58 - M58". astropixels.com. Retrieved 2025-12-15.
15. "How bright is Andromeda's center, in magnitudes per square arcminute or something similar?". Astronomy Stack Exchange. Retrieved 2025-11-15.
16. admin (2015-04-28). "Messier 31: Andromeda Galaxy". Messier Objects. Retrieved 2025-11-15.
17. "Messier 31 - M31 - Andromeda Galaxy". astropixels.com. Retrieved 2025-11-15.
18. "ESA Science & Technology - ISO unveils the hidden rings of Andromeda". sci.esa.int. Retrieved 2025-11-18.
19. "Messier 87 - NASA Science". 2017-10-19. Retrieved 2025-11-15.
20. "Messier 87 - M87". astropixels.com. Retrieved 2025-11-15.
21. "Messier 49 - NASA Science". 2022-08-26. Retrieved 2025-12-03.
22. "Messier 49 - M49". astropixels.com. Retrieved 2025-12-03.
23. "Messier 33 (The Triangulum Galaxy) - NASA Science". 2019-01-07. Retrieved 2025-11-15.
24. "The Triangulum Galaxy | Second Nearest Spiral Galaxy to the Milky Way". AstroBackyard. Retrieved 2025-11-15.