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J/MNRAS/346/1143    VI photometry of Collinder 121           (Burningham+, 2003)
On the nature of Collinder 121: insights from the low-mass pre-main sequence.
    Burningham B., Naylor T., Jeffries R.D., Devey C.R.
   <Mon. Not. R. Astron. Soc., 346, 1143-1150 (2003)>
   =2003MNRAS.346.1143B    (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Stars, pre-main sequence ; X-ray sources ;
              Photometry
Keywords: techniques: photometric - stars: formation -
          stars: low-mass, brown dwarfs -
          open clusters and associations: Cr 121 -
          open clusters and associations: CMa OB 2 - X-rays: stars

Abstract:
    We present a VI photometric catalogue towards the open cluster Cr 121.
    XMM-Newton and ROSAT data are used to discover a low-mass pre-main
    sequence (PMS) along this sightline. de Zeeuw et al. (1999, Cat.
    J/AJ/117/354) have identified Cr 121 as a moving group, using
    Hipparcos data, at a distance of 592pc; we reject the scenario that
    these low-mass PMS stars are associated with that association.
    By considering the higher mass main sequence stellar membership of the
    groups along this sightline, the density of low-mass PMS stars and
    their age spread we argue that the low-mass PMS stars are associated
    with a young, compact cluster at a distance of 1050pc.

Description:
    The VI CCD imaging of 8 13.5-arcmin FoVs centred on WR 6 was carried
    out using the 0.9-m telescope at the Cerro Tololo Interamerican
    Observatory (CTIO) in Chile on the night of 2002 February 12/13.
Objects:
    -----------------------------------------
       RA   (2000)   DE     Designation(s)
    -----------------------------------------
    06 54 12      -24 25.0  Collinder 121
    -----------------------------------------

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table1.dat       112    27502   Photometric catalogue
table2.dat        63      138   XMM-Newton source list
table3.dat        64       13   The reduced ROSAT source list


See also:
        IX/30 : Second ROSAT PSPC Catalog (ROSAT, 2000)
        IX/37 : XMM-Newton Serendipitous Source Catalogue (1XMM) (XMM-SSC, 2003)
 J/AJ/117/354 : OB associations from Hipparcos (de Zeeuw+, 1999)


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

   Bytes Format Units   Label   Explanations

   1-  6  A6    ---     BNJ     Star designation, Cl* Collinder 121 BNJ N-NNNN
   9- 10  I2    h       RAh     Right ascension (J2000.0)
  12- 13  I2    min     RAm     Right ascension (J2000.0)
  15- 20  F6.3  s       RAs     Right ascension (J2000.0)
      22  A1    ---     DE-     Declination sign (J2000.0)
  23- 24  I2    deg     DEd     Declination (J2000.0)
  26- 27  I2    arcmin  DEm     Declination (J2000.0)
  29- 33  F5.2  arcsec  DEs     Declination (J2000.0)
  36- 43  F8.3  pix     Xpos    X position
  46- 53  F8.3  pix     Ypos    Y position
  58- 64  F7.3  mag     Vmag    ?=99.999 V magnitude
  69- 75  F7.3  mag     e_Vmag  ?=99.999 rms uncertainty on Vmag
      78  A1    ---     q_Vmag  Quality flag on Vmag (1)
      79  A1    ---    q_Icmag  Quality flag on Icmag (1)
  81- 88  F8.3  mag     V-Ic    ?=99.999 Cousins V-I colour index
  93- 99  F7.3  mag     e_V-Ic  ?=99.999 rms uncertainty on V-Ic
 102-103  A2    ---     ---     Same as 78- 79
 105-107  A3    ---     PMM     [PMM ]   PMM: X-ray-selected PMS stars which
                                               were also proper motion members
 109-112  A4    ---     NPMM    [NPMM ] NPMM: X-ray-selected PMS stars which
                                               were not proper motion members

Note (1): Quality flags are as follows:
    O: O.K.
    N: Non-stellar
    E: Too close to CCD edge
    B: Background fit failed
    I: Ill-determined background
    P: Position fit failed
    S: Saturated
    E: Too close to edge
    F: Flagged pixel
    R: Uncalibrated region
    A: Absent input data
    M: Negative (minus) counts
    V: Variable
    C: Large relative transparency correction (cloudy)


Byte-by-byte Description of file: table2.dat

   Bytes Format Units   Label   Explanations

   1-  3  I3    ---     XMM     XMM source index number (1)
       4  A1    ---     n_XMM   [s] s: source from the S308 XMM-Newton pointing
   6-  7  I2    h       RAh     XMM Right ascension (J2000.0)
   9- 10  I2    min     RAm     XMM Right ascension (J2000.0)
  12- 17  F6.3  s       RAs     XMM Right ascension (J2000.0)
      19  A1    ---     DE-     XMM Declination sign (J2000.0)
  20- 21  I2    deg     DEd     XMM Declination (J2000.0)
  23- 24  I2    arcmin  DEm     XMM Declination (J2000.0)
  26- 30  F5.2  arcsec  DEs     XMM Declination (J2000.0)
  32- 37  F6.3  arcsec  Offset  Offset from optical position
  39- 43  F5.3  ct/s    CR      EPIC count rate
  45- 49  F5.3  ct/s    e_CR    rms uncertainty on CR
  51- 56  A6    ---     BNJ     ? Star number for optical counterpart
  58- 63  A6    ---     Old     Old star number, in version before 07-Oct-2004

Note (1): XMM numbers:
    [BNJ2003] XMM NNN, 1-152
    [BNJ2003] XMM NNNs, 4s-118s


Byte-by-byte Description of file: table3.dat

   Bytes Format Units    Label    Explanations

   1-  2  I2    ---      ROSAT    ROSAT source index number, [BNJ2003] ROSAT NN
   5-  6  I2    h        RAh      ROSAT Right ascension (J2000.0)
   8-  9  I2    min      RAm      ROSAT Right ascension (J2000.0)
  11- 16  F6.3  s        RAs      ROSAT Right ascension (J2000.0)
      18  A1    ---      DE-      ROSAT Declination sign (J2000.0)
  19- 20  I2    deg      DEd      ROSAT Declination (J2000.0)
  22- 23  I2    arcmin   DEm      ROSAT Declination (J2000.0)
  25- 29  F5.2  arcsec   DEs      ROSAT Declination (J2000.0)
  31- 36  F6.3  pix      Xpos     X position in the PSCP FoV
  38- 43  F6.3  pix      Ypos     Y position in the PSCP FoV
  45- 50  F6.3 10-15W/m2 Flux     ROSAT flux
  52- 57  A6    ---      BNJ      Star designation, for optical counterpart
  59- 64  A6    ---      Old      Old star number, in version before 07-Oct-2004


History: Copied at http://www.astro.ex.ac.uk/people/timn/Catalogues/

(End)                       James Marcout, Patricia Vannier [CDS]    15-Jan-2004