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Description
This table contains some of the results from the first paper of a series devoted to the Lambda Orionis star-forming region, Orion's Head, from the X-ray perspective. The final aim of this research is to provide a comprehensive view of this complex region, which includes several distinct associations and dark clouds. The authors aim to uncover the population of the central, young star cluster Collinder 69, and in particular to find those diskless Class III pre-main sequence objects which have not been identified by previous surveys based on near- and mid-infrared searches, and to establish the X-ray luminosity function for the association. The authors have combined two exposures taken with the XMM-Newton satellite with an exhaustive data set of optical, near- and mid-infrared photometry to assess the membership of the X-ray sources based on different color-color and color-magnitude diagrams, as well as other properties, such as effective temperatures, masses and bolometric luminosities derived from spectral energy distribution fitting and comparison with theoretical isochrones. The presence of circumstellar disks is discussed using mid-infrared photometry from the Spitzer Space Telescope. The authors searched for optical and IR counterparts for their X-ray detections, using a radius of 5.1 arcseconds. This search radius is motivated by the astrometry of XMM-Newton (~ 1-2 arcsec) and the statistical errors of the X-ray sources (<= 4 arcsecs). Multiple counterparts were found for several X-ray sources within their search radius. The visual inspection of all optical and IR images indicated that in a few cases there were additional possible counterparts even slightly beyond this search radius. In order to be as comprehensive as possible, the authors have also retained them. They compiled a master catalog with all sources that were present in at least one of the mappings (optical, near-IR or mid-IR) and extracted the photometry from these surveys. The photometry of all possible counterparts to X-ray sources is listed in this table. The reference sources for the optical and infrared magnitudes are discussed in Section 3 of the reference paper. In this table, they are coded as follows: <pre> Code Reference Source 1 = 2MASS Catalog, CDS Cat. II/246 2 = XMM-Newton Optical Monitor (XMM OM) 3 = Spitzer 4 = Omega 2000 Camera photometry in 2005 5 = CFHT1999 Survey 6 = Barrado y Navascues et al. (2004 ApJ, 610, 1064; 2007 ApJ, 664, 481) 7 = Dolan & Mathieu (1999 AJ, 118, 2409; 2001 AJ, 121, 2124) 8 = Dolan & Mathieu (2002 AJ, 123, 387) 9 = Omega 2000 Camera photometry in 2007 </pre> Thus, this table contains optical and infrared data, as well as membership information, on 205 possible counterparts to the 164 XMM-Newton X-ray sources detected in EPIC observations of the Collinder 69, East and West Fields (C69E and C69W), respectively, with maximum likelihood (ML) values > 15.0. A companion HEASARC Browse table COLL69XMM contains the X-ray data for these X-ray sources. This table was created by the HEASARC in July 2011 based on the electronic versions of Tables 5, 6, 8 and 9 from the reference paper which were obtained from the CDS (their catalog J/A+A/526/A21 files table5.dat, table6.dat, table8.dat and table9.dat). This is a service provided by NASA HEASARC .
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