| Dragonfly 44 | |
|---|---|
| Observation data | |
| Constellation | Coma Berenices |
| Right ascension | 13h 00m 58.0s[1] |
| Declination | +26° 58′ 35″[1] |
| Redshift | ~0.023 |
| Heliocentric radial velocity | 6280 ± 120 km/s |
| Distance | ~100 Mpc (~330 Mly) |
| Group or cluster | Coma Cluster |
| Apparent magnitude (V) | 21 mag; or 19.4 mag [1] |
| Apparent magnitude (B) | 22 |
| Absolute magnitude (V) | -16.1 mag [1] |
| Characteristics | |
| Mass | ~1.0×1012 M☉ |
| Size | 70,000 |
| Apparent size (V) | 10 x 35 arcsec |
| Other designations | |
| SDSS J130057.98+265839.6, SDSS J130058.17+265836.1, SDSS J130058.21+265829.3 | |
Dragonfly 44 is an ultra diffuse galaxy in the Coma Cluster.[2][3][1][4] Observations of the velocity dispersion suggest a mass of about one trillion solar masses, about the same as the mass of the Milky Way; the galaxy shows no evidence of rotation.[5] This is also consistent with about 90 globular clusters observed around Dragonfly 44. However, the galaxy emits only 1% of the light emitted by the Milky Way.[6] The galaxy was discovered with the Dragonfly Telephoto Array.[7]
To determine the amount of dark matter in this galaxy, they used the DEIMOS instrument installed on Keck II to measure the velocities of stars for 33.5 hours over a period of six nights so they could determine the galaxy’s mass.
The scientists then used the Gemini Multi-Object Spectrograph on the 8-m Gemini North telescope to reveal a halo of spherical clusters of stars around the galaxy’s core.Cite error: The <ref> tag has too many names (see the help page).[8][9]
See also
edit- Dark galaxy
- Low-surface-brightness galaxy (LSB galaxy)
- Type-cD galaxy or c-Diffuse galaxy type
- Type-D galaxy or Diffuse-type galaxy
References
edit- ^ a b c d e Van Dokkum, Pieter; et al. (1 May 2015). "Spectroscopic confirmation of the existence of large, diffuse galaxies in the coma cluster". The Astrophysical Journal Letters. 804: L26. arXiv:1504.03320. Bibcode:2015ApJ...804L..26V. doi:10.1088/2041-8205/804/1/L26. Retrieved 1 September 2016.
- ^ "Scientists discover the fluffiest galaxies". phys.org. 14 May 2015.
- ^ Van Dokkum, Pieter; et al. (7 January 2015). "Forty-seven milky way-sized, extremely diffuse galaxies in the Coma-Cluster". The Astrophysical Journal Letters. 798 (2): L45. arXiv:1410.8141. Bibcode:2015ApJ...798L..45V. doi:10.1088/2041-8205/798/2/L45. Retrieved 31 August 2016.
- ^ Dragonfly 44: Ultra-Diffuse Galaxy Made Mostly of Dark Matter. Aug 2016
- ^ Cite error: The named reference
AJL-20160825was invoked but never defined (see the help page). - ^ Crosswell, Ken (26 July 2016). "The Milky Way's dark twin revealed". Nature News. Retrieved 30 July 2016.
- ^ Rachel Feltman (25 August 2016). "A new class of galaxy has been discovered, one made almost entirely of dark matter". Washington Post.
- ^ Hall, Shannon (25 August 2016). "Ghost galaxy is 99.99 per cent dark matter with almost no stars". New Scientist. Retrieved 27 August 2016.
- ^ Feltman, Rachael (26 August 2016). "A new class of galaxy has been discovered, one made almost entirely of dark matter". The Washington Post. Retrieved 26 August 2016.
| Morphology | |
|---|---|
| Structure | |
| Active nuclei | |
| Energetic galaxies | |
| Low activity | |
| Interaction | |
| Lists | |
| See also |
|
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