Antlia II

Antlia II (Ant II) is a low-surface-brightness dwarf satellite galaxy of the Milky Way at a galactic latitude of 11.2°. It spans 1.26° in the sky just southeast of Epsilon Antliae. The galaxy is similar in size to the Large Magellanic Cloud, despite being 1/10,000 as bright. Antlia II has the lowest surface brightness of any galaxy discovered^[4] and is ~ 100 times more diffuse than any known ultra diffuse galaxy.^[1] The large size of the galaxy suggests that it is currently being tidally disrupted, and is in the process of becoming a stellar stream.^[3] The southeast side of Antlia II is farther away than the northwest side, likely due to the tidal disruption.^[2] It was discovered using data from the European Space Agency's Gaia spacecraft in November 2018.

Antlia II
Illustration
Observation data (J2000 epoch)
Pronunciation	/ˈæntliə ... /
Constellation	Antlia
Right ascension	9h 35m 32.832s[1]
Declination	-36° -46m -2.28s[1]
Distance	405,000 ly (124.1 kpc)[2]
Absolute magnitude (V)	−9.86±0.08 mag[3]
Characteristics
Half-light radius (physical)	2.5 kpc[3]
Half-light radius (apparent)	1.10°
Other designations
Ant 2

See also

• Crater 2 Dwarf
• Antlia Dwarf
• Satellite galaxies of the Milky Way

References

1. Torrealba, G.; Belokurov, V.; Koposov, S. E.; Li, T. S.; Walker, M. G.; Sanders, J. L.; Geringer-Sameth, A.; Zucker, D. B.; Kuehn, K.; Evans, N. W.; Dehnen, W. (2019). "The hidden giant: Discovery of an enormous Galactic dwarf satellite in Gaia DR2". Monthly Notices of the Royal Astronomical Society. 488 (2): 2743–2766. arXiv:1811.04082. Bibcode:2019MNRAS.488.2743T. doi:10.1093/mnras/stz1624. S2CID 118867213.
2. Vivas, A. Katherina; Martínez-Vázquez, Clara E.; Walker, Alistair R.; Belokurov, Vasily; Li, Ting S.; Erkal, Denis (2022). "Variable Stars in the Giant Satellite Galaxy Antlia 2". The Astrophysical Journal. 926 (1): 78. arXiv:2112.08467. Bibcode:2022ApJ...926...78V. doi:10.3847/1538-4357/ac43bd. S2CID 245219267.
3. Ji, Alexander P.; Koposov, Sergey E.; Li, Ting S.; Erkal, Denis; Pace, Andrew B.; Simon, Joshua D.; Belokurov, Vasily; Cullinane, Lara R.; Da Costa, Gary S.; Kuehn, Kyler; Lewis, Geraint F.; MacKey, Dougal; Shipp, Nora; Simpson, Jeffrey D.; Zucker, Daniel B.; Hansen, Terese T.; Bland-Hawthorn, Joss; S5 Collaboration (2021). "Kinematics of Antlia 2 and Crater 2 from the Southern Stellar Stream Spectroscopic Survey (S 5)". The Astrophysical Journal. 921 (1): 32. arXiv:2106.12656. Bibcode:2021ApJ...921...32J. doi:10.3847/1538-4357/ac1869. S2CID 235624056.{{cite journal}}: CS1 maint: numeric names: authors list (link)
4. "ESA's Gaia Spacecraft Spots Ghost Galaxy Lurking In Milky Way's Outskirts". Forbes. Retrieved November 20, 2018.