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J/ApJ/578/405       Neutron stars in NGC 5139                 (Rutledge+, 2002)
A possible transient neutron star in quiescence
in the globular cluster NGC 5139.
    Rutledge R.E., Bildsten L., Brown E.F., Pavlov G.G., Zavlin V.E.
   <Astrophys. J. 578, 405 (2002)>
   =2002ApJ...578..405R
ADC_Keywords: Clusters, globular ; Pulsars ; X-ray sources

Keywords: Galaxy: globular clusters: individual (NGC 3139) - stars: neutron


Description:
    The Chandra/ACIS-I detectors observed NGC 5139 in imaging mode for two
    continuous periods (2000 January 24 02:15-09:46 and January 25
    04:33-17:24 TT) for a total exposure of ∼68.6ks. We combined the two
    observations and analyzed them as one. We searched for point sources
    using CELLDETECT, using only the 0.1-2.5keV energy range, excluding
    regions less than 16 pixels from the detector edges and keeping only
    sources with signal-to-noise ratio (S/N)>5.0. We find 40 X-ray point
    sources over the four ACIS-I chips and chip S2 of ACIS-S, which are
    numbered in order of decreasing S/N in Table 1.

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table1.dat        90       40   Chandra X-Ray Sources in the Field of NGC 5139


Byte-by-byte Description of file: table1.dat

   Bytes Format Units     Label      Explanations

   1-  2  I2    ---       RBB2002b   Sequential number
       3  A1    ---      n_RBB2002b  [c] Note on RBB2002b (1)
   5-  8  F4.1  ---       S/N        Signal-to-noise ratio
  10- 11  I2    h         RAh        Right ascension (J2000)
  13- 14  I2    min       RAm        Right ascension (J2000)
  16- 21  F6.3  s         RAs        Right ascension (J2000)
      23  A1    ---       DE-        Declination sign (J2000)
  24- 25  I2    deg       DEd        Declination (J2000)
  27- 28  I2    arcmin    DEm        Declination (J2000)
  30- 34  F5.2  arcsec    DEs        Declination (J2000)
  36- 39  F4.2  arcsec    e_RAs      ? rms uncertainty on position (2)
  41- 44  F4.2  arcsec    e_DEs      ? rms uncertainty on position (2)
  46- 49  F4.2  ---       Delta/rC   Off-axis in radius core units (3)
  51- 56  F6.2  ---       chi2       ? Reduced chi2 statistic
      58  I1    ---       dof        ? Degree of freedom
      59  A1    ---       n_chi2     [d] d: Object not spectrally analyzed (4)
  61- 65  E5.0  ---      Prob(chi2)  ? Prob(chi2)
      66  A1    ---    n_Prob(chi2)  [n] n: not analysed (no Prob(chi2) value)
  68- 69  I2    eV        kTeff      ? Best fit kTeff value
      71  I1    eV        e_kTeff    ? rms uncertainty on kTeff
  73- 76  F4.1  ph/ks     Counts     Counts (0.1-2.5keV)
  78- 80  F3.1  ph/ks     e_Counts   rms uncertainty on Counts
  82- 84  A3    ---       Type       Type of source (5)
      86  I1    ---       Ref        ? References (6)

Note (1): c: X-ray CELLDETECT positional uncertainty possibly incorrect
     by up to 10" because of large off-axis angle and low S/N.
Note (2): Statistical uncertainty in RA/DE (or both). Systematic positional
     uncertainty is ±0.15" (see text).
Note (3): Radius core (rC) = 156" (Djorgovski & Meylan, 1993,
    ASP Conf. Ser. 50, Structure and Dynamics of Globular Clusters, ed. S.
    G. Djorgovski & G. Meylan (San Francisco: ASP), 376).
Note (4): No chi2, dof and Prob(chi2) values (see text).

Note (5): Types:
     qNS = quiescent transient neutron star
      CV = cataclysmic variable
Note (6): References:
     (1) Cool et al., 1995ApJ...438..719C
     (2) present work
     (3) Carson et al., 2000ApJ...532..461C


History:
    From electronic version of the journal
(End)                         James Marcout, Patricia Bauer [CDS]    09-Dec-2002