Messier 81 (also known as
NGC 3031 or
Bode's Galaxy) is a
grand design spiral galaxy about
12 millionlight-years away in the
constellationUrsa Major. It has a
D25 isophotal diameter of 29.44
kiloparsecs (96,000
light-years).
[2][5] Because of its relative proximity to the
Milky Way galaxy, large size, and
active galactic nucleus (which harbors a 70 million
M☉=10.5px
supermassive black hole), Messier 81 has been studied extensively by professional
astronomers. The galaxy's large size and relatively high brightness also makes it a popular target for
amateur astronomers.
[7] In late February 2022, astronomers reported that M81 may be the source of
FRB 20200120E, a repeating
fast radio burst.
Messier 82 (also known as
NGC 3034,
Cigar Galaxy or
M82) is a
starburst galaxy approximately 12 million
light-years away in the
constellationUrsa Major. It is the second-largest member of the
M81 Group, with the
D25 isophotal diameter of 12.52
kiloparsecs (40,800
light-years).=10.5px It is about five times
more luminous than the
Milky Way and its central region is about one hundred times more luminous. The
starburst activity is thought to have been triggered by interaction with neighboring galaxy
M81. As one of the closest starburst galaxies to Earth, M82 is the prototypical example of this galaxy type.
[7][a]SN 2014J, a
type Ia supernova, was discovered in the galaxy on 21 January 2014.=10.5px In 2014, in studying M82, scientists discovered the brightest pulsar yet known, designated
M82 X-2.
Source: Wikipedia 
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