蜻蜓44星系是后髮座星系團中的一個超稀疏星系[2][3][4]。根據觀測其旋轉速度判斷其質量為一萬億太陽質量，約和銀河系的質量相同。這也和周圍觀測到的90個球狀星團一致。不過此星系發出的光只有銀河系的1%[5]。該星係由蜻蜓望遠鏡頭陣列（Dragonfly Telephoto Array）發現[6]。
2016年8月時，科學家指出蜻蜓44星系幾乎完全是由暗物質組成[7][8][9]。
- ^ 1.0 1.1 1.2 Van Dokkum, Pieter; et al. Spectroscopic confirmation of the existence of large, diffuse galaxies in the coma cluster. The Astrophysical Journal Letters. 1 May 2015 [1 September 2016]. （原始內容存檔於2021-03-30）.
- ^ Scientists discover the fluffiest galaxies. phys.org. 14 May 2015 [2016-08-31]. （原始內容存檔於2016-08-26）.
- ^ Van Dokkum, Pieter; et al. Forty-seven milky way-sized, extremely diffuse galaxies in the Coma-Cluster. The Astrophysical Journal Letters. 7 January 2015 [31 August 2016]. （原始內容存檔於2017-06-06）.
- ^ Dragonfly 44: Ultra-Diffuse Galaxy Made Mostly of Dark Matter. Aug 2016. [2016-08-31]. （原始內容存檔於2020-11-12）.
- ^ Crosswell, Ken. The Milky Way’s dark twin revealed. Nature News. 26 July 2016 [30 July 2016]. （原始內容存檔於2016-10-13）.
- ^ Rachel Feltman. A new class of galaxy has been discovered, one made almost entirely of dark matter. Washington Post. 25 August 2016 [2016-11-01]. （原始內容存檔於2020-12-02）.
- ^ Van Dokkum, Pieter; et al. A High Stellar Velocity Dispersion and ~100 Globular Clusters For The Ultra-Diffuse Galaxy Dragonfly 44. The Astrophysical Journal Letters. 25 August 2016 [27 August 2016]. （原始內容存檔於2019-08-30）.
- ^ Hall, Shannon. Ghost galaxy is 99.99 per cent dark matter with almost no stars. New Scientist. 25 August 2016 [27 August 2016]. （原始內容存檔於2019-04-11）.
- ^ Feltman, Rachael. A new class of galaxy has been discovered, one made almost entirely of dark matter. The Washington Post. 26 August 2016 [26 August 2016]. （原始內容存檔於2018-04-02）.
