Andromeda XIX

For the star, see 19 Andromedae.

Andromeda XIX is a satellite galaxy of the Andromeda Galaxy (M31), a member of the Local Group, like the Milky Way Galaxy.^[3] Andromeda XIX is considered "the most extended dwarf galaxy known in the Local Group",^[4] and has been shown to have a half-light radius of 1.7 kiloparsec (kpc).^[4] It was discovered by the Canada–France–Hawaii Telescope, and is thought to be a dwarf galaxy.

Andromeda XIX
Observation data (J2000 epoch)
Constellation	Andromeda
Right ascension	00h 19m 32.10s[1]
Declination	+35° 02′ 37.1″[1]
Redshift	0.003903[1]
Distance	2,651 kly (812.8 kpc)[2]
Apparent magnitude (V)	−10.1[2]
Absolute magnitude (V)	14.5[2]
Characteristics
Type	dG
Half-light radius (physical)	1700 pc
Notable features	Satellite of Andromeda Galaxy, extremely diffuse
Other designations
And XIX, LEDA 5056919[1]

As with other dwarf galaxies, Andromeda XIX is not producing new stars: 90% of its star formation occurred over 9 billion years ago. However, compared to dwarf galaxies of similar mass Andromeda XIX is extremely diffuse, like Antlia II.^[2]

History

Surveillance was performed during use of the MegaPrime/MegaCam 1 deg2 (camera) on the Canada-France-Hawaii Telescope (CFHT) had mapped the Andromeda Galaxy's stellar halo (one quarter) up to ~150 kpc.^[5] The survey confirmed the clumpiness of Andromeda's stellar halo. It had shown the existence of multiple other dwarf galaxies.^[5] They include: Andromeda XI, XII, XIII, XV, XVI, XVIII, XIX, and XX.^[5]

See also

• List of Andromeda's satellite galaxies