CDROM/AJ/V107/P1745     U, V, and I of M15 (Yanny+ 1994)
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Globular Cluster Photometry with the Hubble Space Telescope. II. U, V, and I
Measurements of M15
      Brian Yanny, Puragra Guhathakurta, John N. Bahcall & Donald P. Schneider
      <1994, AJ, 107, 1745>
      =1994AJ....107.1745Y
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Abstract:
  The projected density distribution of resolved stars near the center of
  M15 is shown to be consistent with either a power-law cusp N(r) ~
  r^alpha, with alpha ~ -0.85 +/- 0.2, or with a King model with a core
  of radius <~ 2" (best fit r(core) = 1.3").  The inferred slope is in
  agreement with the theoretical value, alpha = -0.75, calculated by
  Bahcall and Wolf for the distribution of equal-mass stars surrounding a
  massive black hole and is also consistent with the radial profile
  expected from core collapse without a central black hole.  The object
  AC 214 is a candidate for the central density cusp.  Analysis of Monte
  Carlo simulations of the diffuse light indicates that, using current
  analysis techniques and available data, the residual light is not a
  reliable indicator of the true density distribution.  This is contrary
  to earlier work.  Photometric measurements in V and I of more than
  5x10^3 stars (and in U, V, and I of >~ 1500 stars) are used to
  construct color-magnitude diagrams in the central 1' of M15.  Fourteen
  blue straggler candidates are identified in the inner 20".  The central
  color gradient noticed by previous researchers is caused by a central
  depletion of bright red giant stars rather than an excess of blue
  stragglers or blue horizontal branch stars.

File Summary:
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File Name    Lrecl    Records    Explanations
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table3.dat      37       1186    Stellar photometry and astrometry for M15
                                 (V < 18.1)
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Byte-by-byte Description of file: table3.dat
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   Bytes Format  Units      Label    Explanations
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   1- 4   I4      ---        ID       Identification number
   5-11   F7.2    arcsec     RA      *R.A. offset from AC 211 = ID 653
  12-18   F7.2    arcsec     DE      *Dec. offset from AC 211 = ID 653
  19-24   F6.2    mag        V        Visual magnitude
  25-30   F6.2    mag        V-I      V-I color
  31-36   F6.2    mag        U-V      []? U-V color
  37      A1      ---        n_U-V   *[ab] Note for U-V
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Notes for file: table3.dat
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RA,DE:
  Coordinates are arcsec offsets relative to AC 211 = ID 653.
  ID 653 is at RA(2000)= 21:29:58.26 DEC(2000)=12:10:02.90

n_U-V:
  a - the star is located outside the area covered by the U image.
  b - the star is not detected in U, though the area was covered.
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(End)                                             Lee Brotzman [ADS] 17-May-1994