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J/ApJS/163/306   Chandra study of the Cep B star-forming region  (Getman+, 2006)
Chandra study of the Cepheus B star-forming region: stellar populations and the
initial mass function.
    Getman K.V., Feigelson E.D., Townsley L., Broos P., Garmire G.,
    Tsujimoto M.
   <Astrophys. J. Suppl. Ser., 163, 306-334 (2006)>
   =2006ApJS..163..306G
ADC_Keywords: X-ray sources ; Interstellar medium ; Molecular clouds ;
              Stars, pre-main sequence
Keywords: ISM: individual (Cepheus molecular cloud) -
          open clusters and associations: individual (Cepheus OB3) -
          stars: formation - stars: luminosity function, mass function -
          stars: pre-main-sequence - X-rays: stars

Abstract:
    The Cepheus B (Cep B) molecular cloud and a portion of the nearby
    Cep OB3b OB association, one of the most active regions of star
    formation within 1kpc, have been observed with the ACIS detector on
    board the Chandra X-Ray Observatory. We detect 431 X-ray sources,
    of which 89% are confidently identified as clustered premain-sequence
    (PMS) stars.

Description:
    The observation of Cep B and Cep OB3b was obtained on 2003 March
    11.51-11.88 with the ACIS camera on board Chandra.

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table1.dat       101      431   Basic source properties
table2.dat        88      431   2MASS counterparts
table3.dat        82      431   X-ray spectroscopy and luminosities


See also:
  II/246          : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
  J/MNRAS/341/805 : UBVI CCD photometry of Cep OB3b (Pozzo+, 2003)


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

   Bytes Format Units     Label      Explanations

   1-  3  I3    ---       [GFT2006]  CepB source number
   5- 22  A18   ---       CXOCepB    The IAU designation (HHMMSS.ss+DDMMSS.s)
  24- 33  F10.6 deg       RAdeg      Right ascension in decimal degrees (J2000)
  35- 43  F9.6  deg       DEdeg      Declination in decimal degrees (J2000)
  45- 50  F6.2  arcmin    OAxis      The off-axis angle
  52- 57  F6.1  ct        NetF       Net total band (0.5-8.0keV) counts (1)
  59- 62  F4.1  ct        e_NetF     Error in NetF
  64- 67  F4.1  ct        BkgF       Background total band (0.5-8.0keV)
                                      counts extracted
  69- 74  F6.1  ct        NetH       Net hard band (2.0-8.0keV) counts (1)
  76- 79  F4.2  ---       PSF        Point spread fraction in extracted area at
                                      fiducial energy 1.5keV
  81- 84  F4.1  ---       Sig        Source significance (in sigma)
  86- 89  A4    ---       Anom       Source anomalies (2)
      91  A1    ---       Var        Source variability from K-S test (3)
  93- 96  F4.1  ks        Exp        Effective exposure time
  98-101  F4.2  keV       MedE       Median energy in total band corrected
                                      for background

Note (1): In extracted area.

Note (2): Source anomalies, defined as follows:
    g... = fractional time when source is on a detector (FRACEXPO) is <0.9
    .e.. = source on field edge
    ..p. = source piled up
    ...s = source on readout streak
Note (3): Source variability, defined as follows:
    a = no evidence for variability
    b = possibly variable
    c = definitely variable
    . = no test is performed for sources with <4 counts, or sources in
        chip gaps or on field edges


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

   Bytes Format Units      Label     Explanations

   1-  3  I3    ---       [GFT2006]  CepB source number
   5- 22  A18   ---        CXOCepB   The IAU designation (HHMMSS.ss+DDMMSS.s)
  24- 39  A16   ---        2MASS     The 2MASS source identification
  41- 44  F4.2  arcsec     Offset    ? Chandra-2MASS source positional offset
  46- 50  F5.2  mag        Jmag      ? 2MASS J band brightness
  52- 56  F5.2  mag        Hmag      ? 2MASS H band brightness
  58- 62  F5.2  mag        Ksmag     ? 2MASS Ks band brightness
  64- 66  A3    ---        q_2MASS   2MASS photometric quality flag (1)
  68- 70  A3    ---        f_2MASS   2MASS contamination and confusion flag (2)
  72- 76  F5.2  mag        Av        ? Visual absorption (3)
  78- 82  F5.2  solMass    Mass      ? Stellar mass (3)
  84- 88  F5.2  [solLum]   Lbol      ? Stellar bolometric luminosity (3)

Note (1): This is the phqual flag provided in the 2MASS All-Sky Data Release
         where the three characters refer to the JHK bands, defined as follows:
     A = very high significance detection (>10 SNR);
     B = high significance detection (>7 SNR);
     C = moderate significance detection (>5 SNR);
     D = low significance detection;
     E = point spread fitting poor;
     F = reliable photometric errors not available;
     U = upper limit on magnitude (source not detected);
     X = source is detected but no valid brightness estimate is available.
Note (2): This is the ccflg provided in the 2MASS All-Sky Data Release where
         the three characters refer to the JHK bands, defined as:
     0 = source unaffected by artifacts;
     b = bandmerge confusion (possible multiple source);
     c = photometric confusion from nearby star;
     d = diffraction spike confusion from nearby star;
     p = persistence contamination from nearby star;
     s = electronic stripe from nearby star.
Note (3): From the 2MASS color-magnitude diagram.



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

   Bytes Format Units      Label     Explanations

   1-  3  I3    ---       [GFT2006]  CepB source number
   5- 22  A18   ---        CXOCepB   The IAU designation (HHMMSS.ss+DDMMSS.s)
  24- 28  F5.2  [cm-2]     log(NH)   Log of the Hydrogen column density
  30- 34  F5.2  keV        kT        Plasma energy
  36- 40  F5.2  [10-7W]    Lh        Log of observed hard band (2.0-8.0keV)
                                      luminosity (1)
  42- 45  F4.2  [10-7W]    e_Lh      Error in Lh from simulations (1)
  47- 51  F5.2  [10-7W]    Lhc       Log of estimated hard band luminosity
                                      corrected for absorption (1)
  53- 56  F4.2  [10-7W]    e_Lhc     Error in Lhc from simulations (1)
  58- 62  F5.2  [10-7W]    Lt        Log of observed total band (0.5-8.0keV)
                                      luminosity (1)
  64- 67  F4.2  [10-7W]    e_Lt      Error in Lt from simulations (1)
  69- 73  F5.2  [10-7W]    Ltc       Log of estimated total band luminosity
                                      corrected for absorption (1)
  75- 78  F4.2  [10-7W]    e_Ltc     Error in Ltc from simulations (1)
  80- 82  A3    ---        MMDFl     Source flag (2)

Note (1): In units of erg/s.

Note (2): Three-part flag giving details on spectroscopy method, source
          membership, and stars with K-disks, defined as follows:
     b--  =  spectral results from spectral fits of 174 relatively "bright"
             sources with >20 net counts.
     w--  =  spectral results from NH_IR-MedE interpolation for 212 "weak"
             sources with known NH_IR.
     v--  =  spectral results from fits of ungrouped spectra for 45 "weak"
             sources with unknown NH_IR.
     -e-  =  possible members of the embedded cluster.
     -l-  =  possible members of the lightly absorbed cluster.
     -o-  =  other possible members, found in the molecular cloud,
             not related to the embedded cluster.
     -a-  =  AGN candidates.
     -f-  =  field star candidates.
     --d  =  possible K-disk stars.
     --0  =  stars with no K-disk.


History:
    From electronic version of the journal
(End)                   Greg Schwarz [AAS], Marianne Brouty [CDS]    31-Jul-2007