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CEPBOB3OID - Cep B/OB3 Star-Forming Region Chandra Point Source Optical/IR IDs Catalog

HEASARC
Archive

Overview

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 1 kpc, have been observed with the Infrared Array Camera (IRAC) detector on board the Spitzer Space Telescope. The goals were to study protoplanetary disk evolution and processes of sequential triggered star formation in the region. Out of ~400 pre-main-sequence (PMS) stars selected with an earlier Chandra X-ray Observatory observation, ~95% are identified with mid-infrared sources and most of these are classified as diskless or disk-bearing stars. The discovery of the additional >200 IR-excess low-mass members gives a combined Chandra+Spitzer PMS sample that is almost complete down to 0.5 * Msun outside of the cloud, and somewhat above 1 * Msun in the cloud.

The X-ray observations of the Cep B/Cep OB3b region and their data analysis are described in detail by Getman et al. (2006, CDS Cat. J/ApJS/163/306, HEASARC CEPBOB3CXO table). The 30 ks exposure was obtained on 2003 March 11.51-11.88 with the Advanced CCD Imaging Spectrometer (ACIS) detector on board the Chandra X-ray Observatory as part of the ACIS Instrument Team's Guaranteed Time Observations (ObsId No. 3502, P.I.: G. Garmire). The mid-IR observation of Cep B and Cep OB3b was obtained on 2007 February 18 with the IRAC detector on the Spitzer Space Telescope in the 3.6, 4.5, 5.8, and 8.0 micron channels. This was a General Observer project (program identification No. 30361; P.I.: J. Wang).

This table contains the optical and infrared counterpart information on the 431 X-ray sources detected by Chandra. It does not contain the 224 IR-excess objects which were not detected as X-ray sources (listed in Table 3 of the reference paper) that are thought to be additional low-mass members of this complex.


Catalog Bibcode

2009ApJ...699.1454G

References

Protoplanetary disk evolution around the triggered star-forming region
Cepheus B.
    Getman K.V., Feigelson E.D., Luhman K.L., Sicilia-Aguilar A., Wang J.,
    Garmire G.P.
   <Astrophys. J., 699, 1454-1472 (2009)>
   =2009ApJ...699.1454G    (SIMBAD/NED BibCode)

Provenance

This table was created by the HEASARC in August 2011 primarily based on CDS catalog J/ApJ/699/1454 files table.dat and table 2.dat which list the optical and infrared counterpart information on the 431 X-ray sources detected by Chandra. The names and positions of these X-ray sources were taken from the Getman et al. (2006, ApJS, 163, 306) Catalog, which is available as the HEASARC Browse table CEPBOB3CXO.

Parameters

Source_Number
The uniquely identifying X-ray source number as given by Getman et al. (2006, ApJS, 163, 306) = GFT2006.

Alt_Name
The alternative X-ray source designation as recommended by the Dictionary of Nomenclature of Celestial Objects, e.g., '[GFT2006] 1', for X-ray sources from Getman et al. (2006, ApJS, 163, 306).

Name
The preferred IAU source designation for a X-ray source from the Getman et al. (2006, ApJS, 163, 306) list, using the 'CXOCepB' prefix registered with the CDS Dictionary of Nomenclature of Celestial Objects, and the truncated J2000.0 coordinates (JHHMMSS.ss+DDMMSS.s) of the X-ray source.

RA
The Right Ascension of the X-ray source in the selected equinox. This was given in Getman et al. (2006, ApJS, 163, 306) in J2000.0 decimal degree coordinates to a precision of 10-6 degrees in the original table. An astrometric correction of +0.13" in RA was applied to the original Chandra positions in order to bring them into the 2MASS/Hipparcos reference frame.

Dec
The Declination of the X-ray source in the selected equinox. This was given in Getman et al. (2006, ApJS, 163, 306) in J2000.0 decimal degree coordinates to a precision of 10-6 degrees in the original table. An astrometric correction of +0.13" in RA was applied to the original Chandra positions in order to bring them into the 2MASS/Hipparcos reference frame.

LII
The Galactic Longitude of the X-ray source.

BII
The Galactic Latitude of the X-ray source.

CXO_Opt_Offset
The optical-X-ray positional offset, in arcseconds. The oOptical data are from Mayne et al. (2007, CDS Cat. J/MNRAS/375/1220).

Vmag
The Johnson V-band magnitude of the counterpart to the Chandra X-ray source. The optical data are from Mayne et al. (2007, CDS Cat. J/MNRAS/375/1220).

Vmag_Error
The uncertainty in the Johnson V-band magnitude of the counterpart to the Chandra X-ray source.

VI_Color
The V-Ic color index of the counterpart to the Chandra X-ray source. The optical data are from Mayne et al. (2007, CDS Cat. J/MNRAS/375/1220).

VI_Color_Error
The uncertainty in the V-Ic color index of the counterpart to the Chandra X-ray source.

CXO_2MASS_Offset
The 2MASS-X-ray positional offset, in arcseconds. For the 2MASS source names, see Table 2 of Getman et al. (2006; CDS Cat. J/ApJS/163/306 = HEASARC CEPBOB3CXO table).

Jmag
The 2MASS Johnson J-band magnitude of the counterpart to the Chandra X-ray source.

Jmag_Error
The uncertainty in the 2MASS Johnson J-band magnitude of the counterpart to the Chandra X-ray source.

Hmag
The 2MASS Johnson H-band magnitude of the counterpart to the Chandra X-ray source.

Hmag_Error
The uncertainty in the 2MASS Johnson H-band magnitude of the counterpart to the Chandra X-ray source.

Ks_Mag
The 2MASS Johnson Ks-band magnitude of the counterpart to the Chandra X-ray source.

Ks_Mag_Error
The uncertainty in the 2MASS Johnson Ks-band magnitude of the counterpart to the Chandra X-ray source.

TwoMASS_Flags
The 2MASS photometry quality (first 3 characters) and confusion/contamination (second 3 characters) flags. In each case, the three characters refer to the J, H, Ks bands. The codes for the quality flags are 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
  
while the codes for the confusion/contamination flags are:
         0 = source unaffected by artifacts
         b = band-merge 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
  

CXO_IRAC_Offset
THe Spitzer IRAC-X-ray positional offset, in arcseconds. For the most of the sources the reported offset is for the IRAC source taken from the 3.6um-band image. When 3.6um data are not available, the reported offset is for the IRAC source from the 4.5um-band image.

IRAC_3p6_um_Mag
The Spitzer/IRAC magnitude in the 3.6-micron band for the counterpart to the Chandra X-ray source as derived in this study.

IRAC_3p6_um_Mag_Error
The uncertainty in the Spitzer/IRAC magnitude in the 3.6-micron band for the counterpart to the Chandra X-ray source.

IRAC_4p5_um_Mag
The Spitzer/IRAC magnitude in the 4.5-micron band for the counterpart to the Chandra X-ray source as derived in this study.

IRAC_4p5_um_Mag_Error
The uncertainty in the Spitzer/IRAC magnitude in the 4.5-micron band for the counterpart to the Chandra X-ray source.

IRAC_5p8_um_Mag
The Spitzer/IRAC magnitude in the 5.8-micron band for the counterpart to the Chandra X-ray source as derived in this study.

IRAC_5p8_um_Mag_Error
The uncertainty in the Spitzer/IRAC magnitude in the 5.8-micron band for the counterpart to the Chandra X-ray source.

IRAC_8p0_um_Mag
The Spitzer/IRAC magnitude in the 8.0-micron band for the counterpart to the Chandra X-ray source as derived in this study.

IRAC_8p0_um_Mag_Error
The uncertainty in the Spitzer/IRAC magnitude in the 8.0-micron band for the counterpart to the Chandra X-ray source.

IRAC_Qual_Flag
The IRAC photometric aperture and confusion/contamination flag. This four digit flag (one digit for each of the 4 IRAC bands) presents the apertures for the source photometry extraction and indicates the relative degree of source contamination from nearby source(s) and from extended nebular IR emission:

     2 = pixel aperture with likely high level of contamination,
     3 = pixel aperture with likely moderate contamination,
     4 = pixel aperture with likely low level of source contamination,
     9 = inability to derive photometry due to the following possible reasons:
         (a) the source may be out of the channel's FOV (this is further
         clarified by the value of the irac_pos_flag parameter), (b) a weak
         source (or no source) below the detection threshold, (c) the presence
         of strong contamination/confusion from/with nearby source(s) or from
         bright diffuse nebular emission.
  

IRAC_Sed_Slope
The observed slope of the spectral energy distribution (SED) from the IRAC photometry.

IRAC_Sed_Slope_Error
the 1-sigma uncertainty in the observed slope of the spectral energy distribution (SED) from the IRAC photometry.

Num_Bands_Sed_Slope
The number of IRAC bands from which the SED slope was derived.

Jmag_Extinction
The J-band source extinction, in magnitudes. This and the stellar mass were derived from the J versus J-H color-magnitude diagram by dereddening the observed 2MASS photometric colors to the 3(2)Myr PMS isochrones for the CepOB3b/S155 (CepB) regions, assuming a distance of 725 pc.

Stellar_Mass
The stellar mass, in solar masses. This and the J-band extinction were derived from the J versus J-H color-magnitude diagram by dereddening the observed 2MASS photometric colors to the 3(2)Myr PMS isochrones for the CepOB3b/S155 (CepB) regions, assuming a distance of 725 pc.

Broad_Type
The membership and young stellar object (YSO) classification of the source. The membership is from Getman et al. (2006; CDS Cat. J/ApJS/163/306) and the YSO class is derived in the present paper, as follows:

     EXG = possible extragalactic contaminant;
     FRG = possible foreground contaminant;
     DSK = possible disk-bearing YSO;
     NoD = possible diskless YSO (the DSK or NoD classification is based on the
           comparison of the observed Cepheus SEDs with the reddened or
           dereddened median SEDs of YSOs in the IC 348 region (Lada et al.2006;
           CDS Cat. J/AJ/131/1574) as described in the text of the reference
           paper);
     UNC = object of the uncertain class (however, according to the authors,
           many of these are likely to be YSO members with unavailable or
           unreliable IR data).
  

Td_Flag
This flag parameter is set to 'TD' to indicate possible transition disk candidates as based on the authors' visual inspection of SEDs.

CCD_Flag
This 3-digit flag parameter indicates the source position in the IR color-color diagrams (C-CDs). The first digit is for the 3.6-4.5 micron vs. 5.8-8.0 micron diagram, the second digit is for the 3.6-4.5 um vs. 4.5-5.8 um diagram, and the third digit is for the Ks-3.6 vs. 3.6-4.5 um diagram. This flag may either warn about possible inconsistencies of the YSO classifications based on the authors' visual inspection of the SEDs (specified in the broad_type parameter) with that of the C-CDs, or indicate interesting objects, such as transition object candidates. The flag values have the following meanings:

     0 = the YSO classification (broad_type parameter value) is consistent with
         the formal loci of disk or diskless stars on a corresponding C-CD;
     1 = disk-bearing YSO candidate (from broad_type parameter value) is at the
         formal locus of diskless stars on the corresponding C-CD;
     2 = diskless YSO candidate (broad_type parameter value) is at the formal
         locus of disk-bearing stars on the corresponding C-CD;
     3 = not a YSO member (broad_type parameter value) or not enough information
         to place a member on the corresponding C-CD.
  

Subregion_Name
The subregion in which the source's (projected) position lies, as follows:

    CepOB3b = area of the lightly absorbed Cepheus OB3b cluster;
    CepB    = area of the molecular cloud, Cepheus B, with the embedded stellar
              cluster;
    S155    = the HII region interface between the molecular cloud and the
              Cepheus OB3b region.
  

IRAC_Pos_Flag
The 4-digit positional flag (one digit for each IRAC channel) indicating if the source position is outside the field of view (FOV) of IRAC channel, coded as follows:

      0 = source is within the FOV of the corresponding IRAC channel;
      1 = source is outside of the FOV of the corresponding IRAC channel.
  

Contact Person

Questions regarding the CEPBOB3OID database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 5-Aug-2011