NGC 5557 explained

Epoch:J2000
Constellation Name:Boötes
Ra:[1]
H Radial V:3210 ± 28 km/s
Z:0.010764
Dist Ly:[2]
Type:E1
Appmag V:12.2[3]
Absmag V:-22.39[4]
Names:[5]

NGC 5557 is an elliptical galaxy in the constellation Boötes. It was discovered by William Herschel on May 1, 1785.[3] The distance to NGC 5557 is not well known, but it is estimated to be about 127 million light-years (38.8 megaparsecs) away.[2]

NGC 5557 is quite massive, with a K-band absolute magnitude of -24.8, and is a slow rotator,[2] which suggests it gained mass through dry mergers (galaxy mergers involving galaxies significant amounts of gas).[4] However, it has a faint tidal tail to its east, as well as a more complex structure to the west. This structure, if found to be connected to NGC 5557, would one of the largest around a galaxy, spanning about 1.1 million light-years (350,000 parsecs).[2] This filamentary structure suggests that NGC 5557 may have formed from a more gas-rich galaxy merger a couple billion years ago.[2] This implies that the galaxy merger would need to have a low impact parameter.[4]

NGC 5557 is part of a galaxy group,[2] [3] and is the largest such galaxy in the group by far.[2] Surrounding the galaxy near the eastern filament are several small bluish objects, which are possibly tidal dwarf galaxies.[2]

Two supernovae have been observed in NGC 5557: SN 1996aa (type Ia, mag. 17),[6] and SN 2013gn (type Ia, mag. 15.3).[7]

Notes and References

  1. 10.1086/498708 . Skrutskie . Michael F. . Cutri . Roc M. . Stiening . Rae . Weinberg . Martin D. . Schneider . Stephen E. . Carpenter . John M. . Beichman . Charles A. . Capps . Richard W. . Chester . Thomas . Elias . Jonathan H. . Huchra . John P. . Liebert . James W. . Lonsdale . Carol J. . Monet . David G. . Price . Stephan . Seitzer . Patrick . Jarrett . Thomas H. . Kirkpatrick . J. Davy . Gizis . John E. . Howard . Elizabeth V. . Evans . Tracey E. . Fowler . John W. . Fullmer . Linda . Hurt . Robert L. . Light . Robert M. . Kopan . Eugene L. . Marsh . Kenneth A. . McCallon . Howard L. . Tam . Robert . Van Dyk . Schuyler D. . Wheelock . Sherry L. . The Two Micron All Sky Survey (2MASS) . The Astronomical Journal . 1 February 2006 . 131 . 2 . 1163–1183 . 2006AJ....131.1163S . 18913331 . 0004-6256 . free .
  2. 10.1111/j.1365-2966.2011.19137.x. The ATLAS3D project - IX. The merger origin of a fast- and a slow-rotating early-type galaxy revealed with deep optical imaging: First results. 2011. Duc. Pierre-Alain. Cuillandre. Jean-Charles. Serra. Paolo. Michel-Dansac. Leo. Ferriere. Etienne. Alatalo. Katherine. Blitz. Leo. Bois. Maxime. Bournaud. Frédéric. Bureau. Martin. Cappellari. Michele. Davies. Roger L.. Davis. Timothy A.. De Zeeuw. P. T.. Emsellem. Eric. Khochfar. Sadegh. Krajnović. Davor. Kuntschner. Harald. Lablanche. Pierre-Yves. McDermid. Richard M.. Morganti. Raffaella. Raffaella Morganti. Naab. Thorsten. Oosterloo. Tom. Sarzi. Marc. Scott. Nicholas. Weijmans. Anne-Marie. Young. Lisa M.. Monthly Notices of the Royal Astronomical Society. 417. 2. 863–881. free . 1105.5654. 2011MNRAS.417..863D. 6762647.
  3. Web site: New General Catalogue objects: NGC 5550 - 5599. Seligman, Courtney. cseligman.com. 2021-04-17.
  4. 10.1086/678566. GALFIT-CORSAIR: Implementing the Core-Sérsic Model into GALFIT. 2014. Bonfini. Paolo. Publications of the Astronomical Society of the Pacific. 126. 944. 935–947. 1408.6846. 2014PASP..126..935B. 119256809.
  5. NGC 5557. 2021-04-17.
  6. https://www.wis-tns.org/object/1996aa Transient Name Server entry for SN 1996aa.
  7. https://www.wis-tns.org/object/2013gn Transient Name Server entry for SN 2013gn.

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