Access to Astronomical Catalogues

J/ApJ/589/509       Chandra observations of Trumpler 14 and 16    (Evans+, 2003)
Chandra observations of associates of η Carinae. I. Luminosities.
    Evans N.R., Seward F.D., Krauss M.I., Isobe T., Nichols J., Schlegel E.M.,
    Wolk S.J.
   <Astrophys. J. 589, 509 (2003)>
   =2003ApJ...589..509E
ADC_Keywords: Clusters, open ; X-ray sources ; Photometry

Keywords: open clusters and associations: individual: Trumpler 14, Trumpler 16 -
          X-rays: stars

Abstract:
    The region around the η Carinae Nebula has three OB associations,
    which contain a Wolf-Rayet star and several massive O3 stars. An early
    Chandra ACIS-I image was centered on η Car and includes Trumpler
    16 and part of Trumpler 14. The Chandra image confirms the well-known
    result that O and very early B stars are X-ray sources with
    LX~=10-7Lbol over an X-ray luminosity range of about 100. Two new,
    anomalously strong X-ray sources have been found among the hot star
    population: Tr 16-244, a heavily reddened O3 I star, and Tr 16-22, a
    heavily reddened O8.5 V star. Two stars have an unusually large
    LX/Lbol: HD 93162, a Wolf-Rayet star (and possible binary), and
    Tr 16-22, a possible colliding-wind binary. In addition, a population
    of sources associated with cool stars is detected. In the
    color-magnitude diagram, these X-ray sources sit above the sequence of
    field stars in the Carina arm. The OB stars are on average more X-ray
    luminous than the cool star X-ray sources. X-ray sources among A stars
    have X-ray luminosities similar to those of cooler stars and may be
    due to cooler companions. Upper limits are presented for B stars that
    are not detected in X-rays. These upper limits are also the upper
    limits for any cool companions that the hot stars may have. Hardness
    ratios are presented for the most luminous sources in bands 0.5-0.9,
    0.9-1.5, and 1.5-2.04keV. The available information on the binary
    nature of the hot stars is discussed, but binarity does not correlate
    with X-ray strength in a simple way.

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
tab12.dat         83      154   X-Ray Sources: OB stars and Not OB Stars
                             (tables 1 and 2 of the paper)
tab34.dat         55      154   X-Ray Sources: Hardness Ratios:
                             OB Stars and Not OB stars
                             (tables 3 and 4 of the paper)
table5.dat        53      132   Photometry of Low Mass X-ray sources
tab68.dat         68       23   X-Ray Sources: Hot Star Identifications and
                             Binaries Velocities (tables 6 and 8 of the paper)
table7.dat        74       32   Non-detections: OB Stars


See also:
   J/AJ/105/980  : Stellar content of Tr 14 and Tr 16 (Massey+ 1993)
   J/ApJ/549/578 : BV photometry of Trumpler 14 and 16 (Degioia-Eastwood+, 2001)
   J/A+AS/116/75 : Region of the open cluster Tr 14 (Vazquez+, 1996)
   J/AJ/105/1822 : Open clusters near eta Car (Cudworth+ 1993)


Byte-by-byte Description of file: tab12.dat

   Bytes Format Units   Label     Explanations

   1-  3  A3    ---     Sample    [N OB] OB: OB stars, NOB: Not OB stars
   5-  7  I3    ---    [ESK2003]  Source number
   9- 10  I2    h       RAh       Hour of Right Ascension (J2000)
  12- 13  I2    min     RAm       Minute of Right Ascension (J2000)
  15- 19  F5.2  s       RAs       Second of Right Ascension (J2000)
      21  A1    ---     DE-       Sign of the Declination (J2000)
  22- 23  I2    deg     DEd       Degree of Declination (J2000)
  25- 26  I2    arcmin  DEm       Arcminute of Declination (J2000)
  28- 31  F4.1  arcsec  DEs       Arcsecond of Declination (J2000)
  33- 36  F4.1  arcmin  Rad       The radial distance from the aim point
  38- 43  F6.1  ct      TCts      Total counts from 0.5 to 2.04keV
  45- 48  F4.1  ct      e_TCts    Error in TCts (1)
  50- 54  F5.1  ct      SCts      Soft counts from 0.5 to 0.9keV
  56- 59  F4.1  ct      e_SCts    Error in SCts (1)
  61- 66  F6.1  ct      MCts      Medium counts from 0.9 to 1.5keV
  68- 71  F4.1  ct      e_MCts    Error in MCts (1)
  73- 78  F6.1  ct      HCts      Hard counts from 1.5 to 2.04keV
  80- 83  F4.1  ct      e_HCts    Error in HCts (1)

Note (1): Computed by DMEXTRACT using Poisson statistics.



Byte-by-byte Description of file: tab34.dat

   Bytes Format Units     Label    Explanations

   1-  3  A3    ---       Sample   [N OB] OB: OB stars, NOB: Not OB stars
   5-  7  I3    ---     [ESK2003]  Source number
   9- 13  F5.2  ---       HRMS     The (Medium-Soft)/(Medium+Soft) ratio
  15- 18  F4.2  ---       e_HRMS   Error on HRMS (1)
  20- 24  F5.2  ---       HRHM     ? The (Hard-Medium)/(Hard+Medium) ratio
  26- 29  F4.2  ---       e_HRHM   ? Error on HRHM (1)
  31- 36  F6.2  [mW/m2]   logFX    Log of the X-ray Flux in erg/cm^2^/s (2)
  39- 43  F5.2  [mW/m2]   e_logFX  Error on logFX
  45- 49  F5.2  [10-7W]   logLX    Log of the X-ray luminosity in erg/s (2)
  51- 55  F5.2  [10-7W]   e_logLX  Error in logLX

Note (1): Errors have been propagated from the errors on the energy bands.

Note (2): Fluxes and luminosities have been calculated from total count rates.
    PIMMS (Portable Interactive Multi-Mission Simulator) was used to
    calculate a conversion from counts to energy. The count rates were
    calculated on the basis of 9.630ks of good time. A Raymond-Smith
    plasma model spectrum with logT=6.65 was used, a spectrum typical of a
    stellar source found in young associations. The extinction is fairly
    uniform over the field. A column of NH=3x1021cm-2 was adopted,
    corresponding to E(B-V)=0.52mag, which is typical of the field (Massey
    & Johnson, 1993, Cat. J/AJ/105/980). With these parameters, a
    conversion factor of 1.4x10-11ergs/cm2/s (counts/s) was derived.
    Conversion factors differed by less than a factor of 2 for a range of
    logT from 6.4 to 7.1. Luminosities were derived from fluxes using a
    distance of 2.5kpc


Byte-by-byte Description of file: table5.dat

   Bytes Format Units   Label     Explanations

   1-  3  I3    ---    [ESK2003]  X-Ray identification
   5-  6  I2    h       RAh       Hour of Right Ascension (J2000)
   8-  9  I2    min     RAm       Minute of Right Ascension (J2000)
  11- 15  F5.2  s       RAs       Second of Right Ascension (J2000)
      17  A1    ---     DE-       Sign of the Declination (J2000)
  18- 19  I2    deg     DEd       Degree of Declination (J2000)
  21- 22  I2    arcmin  DEm       Arcminute of Declination (J2000)
  24- 27  F4.1  arcsec  DEs       Arcsecond of Declination (J2000)
  29- 33  F5.3  mag     B-V       ? The (B-V) color index
  35- 40  F6.3  mag     Vmag      ? The V band magnitude
  42- 46  F5.3  mag     V-Ic      ? The (V-Ic) color index
  48- 52  A5    ---  n_[ESK2003]  Individual notes (1)

Note (1): Notes are numbered as follows:
      1 = Two stars;
     1a = Not resolved; not plotted;
     1b =  Not resolved; estimated combined magnitude;
     1c = Resolved; position match poor; not plotted;
     1d = Resolved; likely source used;
      2 = High background;
      3 = Contamination from nearby bright star;
      4 = Uncertain identification;
      5 = Faint star;
      6 = The star is overexposed. V<12.5;
      7 = Outside the observed fields.


Byte-by-byte Description of file: tab68.dat

   Bytes Format Units  Label         Explanations

   1- 12  A12   ---    Name          Optical identification  (1)
  16- 18  I3    ---    [ESK2003]     ? Sequential number
  20- 24  F5.2  mag    Vmag          V magnitude (1)
  26- 32  A7    ---    SpType        MK spectral type
  34- 37  F4.2  mag    E(B-V)        Extinction in B-V (1)
  39- 43  F5.1  mag    Mbol          Bolometric magnitude (2)
  45- 49  F5.2  [---]  log(LX/Lbol)  X-ray luminosity to bolometric luminosity
                                      ratio
      52  A1    ---    Bin           [YN] Binary status
      53  A1    ---    u_Bin         Uncertainty flag on Bin
  55- 57  F3.1  d      Porb          ? Orbital period
      58  A1    ---    ---           [,]
  60- 62  F3.1  d      Porb2         ? Second orbital period
  65- 68  A4    ---    r_Porb        Reference for Porb, separated by comma (3)

Note (1): From Massey & Johnson, 1993, Cat. J/AJ/105/980

Note (2): From Massey et al., 2001AJ....121.1050M

Note (3): References for orbital period are numbered as follows:
      1 = Penny et al., 1993PASP..105..588P
      2 = Levato et al., 1991ApJS...75..869L
      3 = Morrell et al., 2001MNRAS.326...85M
      4 = Albacete Colombo et al., 2001MNRAS.326...78A
      5 = Albacete Colombo et al., 2002MNRAS.336.1099A


Byte-by-byte Description of file: table7.dat

   Bytes Format Units   Label     Explanations

   1-  2  I2    ---     Seq       Source number,
                                   [ESK2003] NotDetected NN in Simbad
   4-  5  I2    h       RAh       Right ascension (J2000.0)
   7-  8  I2    min     RAm       Right ascension (J2000.0)
  10- 14  F5.2  s       RAs       Right ascension (J2000.0)
      16  A1    ---     DE-       Declination sign (J2000.0)
  17- 18  I2    deg     DEd       Declination (J2000.0)
  20- 21  I2    arcmin  DEm       Declination (J2000.0)
  23- 26  F4.1  arcsec  DEs       Declination (J2000.0)
  28- 31  F4.1  ct      CountsSA  Source area counts
  33- 35  F3.1  ct    e_CountsSA  rms uncertainty on e_CountsSA
  37- 41  F5.1  ct      CountsBA  Background area counts
  43- 46  F4.1  ct    e_CountsBA  rms uncertainty on e_CountsBA
  49- 53  F5.1  ct      Counts    Net counts
  55- 57  F3.1  ct      e_Counts  rms uncertainty on Counts
  59- 62  F4.1  arcmin  Rad       Radius
  64- 67  A4    ---     SpType    MK Spectral type
  69- 74  F6.3  [10-7W] logLX     Upper limit of X-ray luminosity


History:
    From electronic version of the journal
(End)                    Greg Schwarz [AAS], Patricia Bauer [CDS]    24-Jun-2003