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Hubble Finds Mysterious Disk of Blue Stars Around Black Hole

by: *Credit:* NASA [ http://www.nasa.gov/ ], ESA [ http://www.spacetelescope.org/ ] and A. Schaller (for STScI [ http://www.stsci.edu/ ])

Publication date: 9/20/2005

Topics: NGC 224, M31, Andromeda Galaxy, What -- Andromeda, What -- Hubble Space Telescope (HST), What -- FAST, What -- Constellation, What -- Planck, Where -- M31, Where -- NGC 224, Where -- Texas, Where -- Austin, Where -- Canada, Where -- Michigan, Where -- Washington

*Description*: This artist's concept shows a view across a mysterious disk of young, blue stars encircling a supermassive black hole at the core of the neighboring Andromeda Galaxy (M31). The region around the black hole is barely visible at the center of the disk. The background stars are the typical older, redder population of stars that inhabit the cores of most galaxies. Spectroscopic observations by the Hubble Space Telescope reveal that the blue light consists of more than 400 stars that formed in a burst of activity about 200 million years ago. The stars are tightly packed in a disk that is only a light-year across. Under the black hole's gravitational grip, the stars are traveling very fast: 2.2 million miles an hour (3.6 million kilometers an hour, or 1,000 kilometers a second). Technical facts about this news release: About the Object Object Name: M31, Andromeda Galaxy, NGC 224 Object Description: Sprial Galaxy Position (J2000): R.A. 00h 42m 44s.31 Dec. +41° 16' 09".4 Constellation: Andromeda Distance: About 2.5 million light-years (0.8 Megaparsecs) Dimensions: The WFPC2 image of M31's nucleus is 11.6 arcminutes (150 light-years or 46.5 parsecs) across. About the Data Science Team: The science team includes R. Bender (Univ. of Sternwarte, Munich; Max Planck Inst., Garching; Univ. of Texas at Austin), J. Kormendy (Univ. of Texas at Austin), G. Bower (CSC/STScI), R. Green (NOAO), J. Thomas (Univ. of Sternwarte, Munich; Max Planck Inst., Garching), A.C. Danks (Bowie, MD), T. Gull (NASA/GSFC), J.B. Hutchings (NRC of Canada), C.L. Joseph (Rutgers Univ.), M.E. Kaiser (JHU), T.R. Lauer (NOAO/AURA/NSF), C.H. Nelson (UNLV), D. Richstone (Univ. of Michigan), D. Weistrop (UNLV), and B. Woodgate (NASA/GSFC). Instrument: WFPC2 STIS Data Description: The science data are from the HST proposal 5236: J. Westphal (Caltech), T.R. Lauer (NOAO/AURA/NSF), S. M. FABER UCO/Lick Observatory, W. Baum (Univ. of Washington) The science data are from the HST proposal 8018: R. Green (NOAO/KPNO) and G. Bower (NOAO). Exposure Date(s): June 18-20, 1995 July 23-24, 1999 Exposure Time: 3.7 hours 6.3 hours Filters: F160BW, F300W ("U"), F555W ("V"), F814W ("I") G430L, G750M About the Image Image Credit: NASA, ESA and T. Lauer (NOAO/AURA/NSF) Release Date: September 20, 2005 Orientation: The Core of the Andromeda Galaxy (M31) [ http://imgsrc.hubblesite.org/hu/db/2005/26/images/d/formats/compass_large_web.jpg ] *News Release Number:*: STScI-2005-26b