Access to Astronomical Catalogues

J/MNRAS/341/805     UBVI CCD photometry of Cep OB3b          (Pozzo+, 2003)
The discovery of low-mass pre-main-sequence stars in Cepheus OB3b.
    Pozzo M., Naylor T., Jeffries R.D., Drew J.E.
   <Mon. Not. R. Astron. Soc., 341, 805-822 (2003)>
   =2003MNRAS.341..805P
ADC_Keywords: Clusters, open ; Photometry, CCD ; Photometry, UBVRI

Keywords: accretion, accretion discs - techniques: radial velocities -
          stars: formation - stars: late-type - stars: pre-main-sequence -
          open clusters and associations: individual: Cepheus OB3

Abstract:
    We report the discovery of a low-mass pre-main-sequence (PMS) stellar
    population in the younger subgroup of the Cepheus OB3 association,
    Cep OB3b, using UBVI CCD photometry and follow-up spectroscopy. The
    optical survey covers approximately 1300arcmin2 on the sky and gives
    a global photometric and astrometric catalogue for more than 7000
    objects. The location of a PMS population is well defined in a V
    versus (V-I) colour-magnitude diagram.

Description:
    The UBVI CCD images were taken on the nights of 1997 August 10/11 and
    11/12, with the 2.5-m Isaac Newton Telescope (INT), La Palma, Canary
    Islands, Spain, equipped with the Wide Field Camera (WFC) and an array
    of four Loral CCDs. Data were taken using filters U (RGO), B (Harris),
    V (Harris) and I (RGO INT-WFC).

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
catalog.dat      119    13657   Photometric catalogue
flags.dat         84       18   Flags


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

   Bytes Format Units   Label     Explanations

   1-  4  F4.2  ---     Field     Field and CCD number (1)
   6-  9  I4    ---     Star      Star number in the field
  12- 13  I2    h       RAh       Right ascension (J2000.0)
  15- 16  I2    min     RAm       Right ascension (J2000.0)
  18- 23  F6.3  s       RAs       [0/60] Right ascension (J2000.0)
      25  A1    ---     DE-       Declination sign (J2000.0)
  26- 27  I2    deg     DEd       Declination (J2000.0)
  29- 30  I2    arcmin  DEm       Declination (J2000.0)
  32- 36  F5.2  arcsec  DEs       [0/60] Declination (J2000.0)
  38- 45  F8.3  pix     Xpos      X position in the CCD image
  47- 54  F8.3  pix     Ypos      Y position in the CCD image
  56- 61  F6.3  mag     Vmag      ? V magnitude
      62  A1    ---     n_Vmag    [I] I for +Inf
  64- 68  F5.3  mag     e_Vmag    rms uncertainty on Vmag
  70- 71  A2    ---     f_Vmag    Flag on Vmag, in flags. dat file
  73- 78  F6.3  mag     B-V       B-V colour index
  80- 84  F5.3  mag     e_B-V     rms uncertainty on B-V
  86- 87  A2    ---     f_B-V     Flag on B-V colour, in flags.dat file
  89- 94  F6.3  mag     V-I       V-I colour index
  96-100  F5.3  mag     e_V-I     rms uncertainty on V-I
 102-103  A2    ---     f_V-I     Flag on V-I colour, in flags.dat file
 105-110  F6.3  mag     U-B       U-B colour index
 112-116  F5.3  mag     e_U-B     rms uncertainty on U-B
 118-119  A2    ---     f_U-B     Flag on U-B colour, in flags.dat file

Note (1): The number before the decimal place is the field number,
          the one after is the CCD number.


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

   Bytes Format Units   Label     Explanations

       1  A1    ---     Flag      Flag code (1)
   3- 49  A47   ---     Explain   Flag meaning
  51- 75  A25   ---    Algorithm  Algorithm used
  77- 82  A6    ---     Type      Type (Strong or Weak)
      84  I1    ---     Fno       ? Flag number for the older versions of
                                    the software

Note (1): If a star is flagged as having negative counts (M),
     the magnitude is replaced with the uncertainty in flux converted into
     magnitudes. Thus magnitudes for objects flagged M should be treated as
     bright (i.e. lower) limits. It also means that colours which are
     quoted for these objects are limits.

     For example a flag of MO in the B-V colour, means that the B magnitude
     is a lower limit, so B-V is a lower limit. The uncertainty becomes
     meaningless, unless you want the description for real aficionados...


History:
    Copied at http://www.astro.ex.ac.uk/people/timn/Catalogues/PNJD2003/
(End)                                      Patricia Vannier [CDS]    05-Apr-2007