The apparent magnitude of the Cartwheel Galaxy is 15.2
The Andromeda Galaxy has an apparent magnitude of +3.44
I assume when you mean brightness, you mean apparent magnitude as opposed to absolute magnitude. The quasar 3C 273 has an apparent magnitude of about 12.8 whereas the brightest galaxy - the Large Magellanic Cloud has an apparent magnitude of 0.9. However, in absolute magnitudes, 3C 273 has an absolute magnitude of about -26.7 very similar to our own Sun.
The magnitude of a galaxy will depend on a lot of factors, luminousity, size and distance from us.The apparent magnitude of the naked eye galaxies are:Large Magellanic Cloud +0.9Small Magellanic Cloud +2.7Andromeda Galaxy +3.4Triangulum Galaxy +5.7Centaurus A +7.8Bode's Galaxy +7.89Sculptor Galaxy +8.0Messier 83 +8.2
The Cartwheel Galaxy is a lenticular galaxy about 500 million light years away in the constellation Sculptor.It is about 150,000 light-years across.
The Cartwheel Galaxy ( ESO 350-40) is a lenticular galaxy about 500 million light years away in the constellation Sculptor.
Antares Absolute and Apparent Magnitude Absolute Magnitude~ -5.2 Apparent Magnitude~ +0.60
The apparent magnitude of Neptune is 7.8
Vega has an apparent magnitude of 0.03.
The two types are apparent magnitude, the magnitude of a star as it appears to us, and absolute magnitude, which is what a star's apparent magnitude would be at a standard distance of ten parsecs.
Fritz Zwicky in 1941
The apparent magnitude is 2.4
The apparent magnitude of a star is a measure of its brightness.