IR20126CXO - IRAS 20126+4104 Chandra X-Ray Point Source Catalog
The authors observed the IRAS 20126+4104 region with the Chandra ACIS-I instrument on 2003 March 17 for a total exposure time of 39.35 ks. C-band (6 cm) continuum observations of the massive star-forming region IRAS 20126+4104 were conducted with the VLA operated by NRAO on 2011 August 7. These X-ray and radio data are augmented by NIR and optical archival data. For the Mid-IR wavelength regions, the authors searched the Spitzer Enhanced Imaging Products Point Source catalog.
X-ray and radio observations of the massive star-forming region IRAS 20126+4104 Montes V.A., Hofner P., Anderson C., Rosero V. <Astrophys. J. Suppl. Ser., 219, 41 (2015)> =2015ApJS..219...41M (SIMBAD/NED BibCode)
A unique identification number for each Chandra source in this catalog in order of increasing J2000.0 Right Ascension.
The J2000.0 position-based Chandra source designation as originally specified in the published catalog (except that the 'CXOU' prefix rather than the 'CXO' prefix has been used). These original names are deprecated because they do not conform with the IAU standard for such names, since the coordinates have been rounded rather than truncated, and the Declination part of the name is given to more precision than the CDS Dictionary of Nomenclature of Celestial Objects recommends.
The corrected J2000.0 position-based Chandra source designation, using the prefix 'CXOU' for Chandra X-ray Observatory, Unregistered. These names conform with the IAU standard for such names, since the coordinates have been truncated rather than rounded, and the Declination part of the name is given to a precision of arcseconds, as the CDS Dictionary of Nomenclature of Celestial Objects recommends for Chandra sources, e.g., 'CXOU J201347.0+411541'.
The Right Ascension of the X-ray source in the selected equinox. This was given in J2000.0 sexagesimal coordinates to a precision of 0.001 seconds of time in the original table.
The Declination of the X-ray source in the selected equinox. This was given in J2000.0 sexagesimal coordinates to a precision of 0.01 arcseconds in the original table.
The Galactic Longitude of the X-ray source.
The Galactic Latitude of the X-ray source.
The observed Chandra ACIS-I count rate of the X-ray source in the 0.5-8 keV band, in counts per second. This was converted by the HEASARC from the units of ct ks-1 used in the original table.
The observed X-ray flux of the source in the 0.5-8 keV band, in erg s-1 cm-2. The details of the models used to fit the X-ray spectra of the Chandra sources and to derive fluxes are given in Section 3.1.3 of the reference paper. No reliable fits were found for 12 of the 150 sources, and for these 12 sources no fluxes are listed.
The hardness ratio, HR, of the X-ray source. HR is defined as (hx - sx)/(hx + sx) where hx is the count rate in the 2-8 keV energy range and sx is the count rate in the 0.5-2 keV band. Values of +/-1.00 for HR thus indicate that the source was only detected in the hard or soft energy bands, respectively. A blank value for the hardness ratio (HR) indicates that the source was only detected in the full (0.5-8 keV) energy range.
The variability of the X-ray source, coded as follows:
V = Variable; FL = Flaring; (blank) = Constant.
The 2MASS near-infrared (NIR) source designation of the counterpart to the X-ray source using the form that the CDS Dictionary of Nomenclature of Celestial Objects recommends, viz., '2MASS JHHMMSSss+DDMMSSs'. The authors used the 2MASS All-Sky Point Source Catalog to find the NIR counterparts. A matching radius of 1 arcsecond was chosen for X-ray sources with off-axis positions of <= 3 arcminutes and was enlarged to 2" for sources with off-axis positions of > 3' because of the off-axis Chandra PSF degradation. With these criteria, the authors found a total of 88 counterparts for the 150 X-ray sources (59%). Most (90%) of the NIR counterparts have high-quality photometry in the JHKs bands.
A non-blank value of this flag indicates the presence of a note concerning the 2MASS counterpart, as follows:
a = Theses sources have in the 2MASS band one or two filter detections with quality flag U. This means that the source is not detected in this band or it is detected but not resolved in a consistent fashion with other bands. The 2MASS data for those sources are not used for the cluster analysis. b = The majority of the 2MASS counterparts have a quality flag A (high-quality photometry) in the three bands, except for nine of them. The photometric quality flags listed for those nine sources, respectively, for the J, H, and Ks bands: source 15 AAC, source 21 AAB, source 36 AAB, source 41 AAE, source 55 BAA, source 61 BAC, source 67 AAB, source 78 BAA, source 111 AEA. c = Spectral type OB star. Identifiers: HD 228515, ALS 11001, CSI+41-20127 1, GSC 03155-00985, LS III +41 6, 2MASS J20142661+4112101, TYC 3155-985-1. e = Spectral type B star. Identifiers: TYC 3155-859-1, ALS 11003, CSI+41-20128 2, GSC 03155-00859, LS III +41 7, 2MASS J20143205+4112498. f = Spectral type F8 star. Identifiers: HD 228527, AG+41 1862, BD+40 4073, GSC 03155-00817, 2MASS J20143246+4114537, PPM 59547, SAO 49350, TYC 3155-817-1. g = Spectral type K5 star. Identifiers: HD 228590, BD+40 4078, GSC 03159-00721, 2MASS J20151437+4115318, TYC 3159-721-1.
The Spitzer Space Telescope (SST) mid-infrared source designation of the counterpart to the X-ray source using the form that the CDS Dictionary of Nomenclature of Celestial Objects recommends for unregistered SST sources, viz., 'SSTU JHHMMSS.ss+DDMMSS.s'. In the original paper, the authors used a prefix of 'SSTSLP' for the SST sources. For the Mid-IR wavelength regions, the authors searched the Spitzer Enhanced Imaging Products Point Source catalog. Using the same procedure as for the 2MASS catalog (q.v.), they found a total of 19 counterparts for the X-ray sources within the entire ACIS field. Qiu et al. (2008, ApJ, 685, 1005) have reported Spitzer IRAC and MIPS observations of a 5' x 5' area of the IRAS 20126+4104 core. The present authors found that only three of their sources have X-ray counterparts: these are also included here.
A non-blank value of this flag indicates the presence of a note concerning the SST counterpart, as follows:
d = Same Spitzer counterparts found as in Qiu et al. (2008, ApJ, 685, 1005).
The JVLA radio source designation of the 6-cm counterpart to the X-ray source using the prefix '[MHA2015] VLA' for 'Montes, Hofner, Anderson 2015 Very Large Array' created by the HEASARC in the style based on the CDS Dictionary of Nomenclature of Celestial Objects recommendations for such sources, and the Galactic coordinates of the source, e.g., '[MHA2015] VLA GLL.llll+B.bbbb'. The authors compared the VLA sources detected in their observation of this region with the ACIS sources in order to find the radio counterparts of the X-ray sources. They found that only four of the ACIS sources have radio counterparts. All the radio counterparts have position differences smaller than 1.0 arcsecond. Their 6-cm flux densities are listed in Table 4 of the original paper.
The USNO-B1 Source designation of the optical counterpart to the X-ray source. The optical counterparts of the ACIS sources were found using the USNO-B1.0 catalog. Applying the same selection criteria as for 2MASS and Spitzer, viz., a matching radius of 1 arcsecond for X-ray sources with off-axis positions of <= 3 arcminutes and a larger one of 2" for sources with off-axis positions of > 3', the authors found that 80 of the ACIS sources (53%) have optical counterparts.
The 2MASS J-band magnitude of the NIR counterpart to the X-ray source.
The 2MASS H-band magnitude of the NIR counterpart to the X-ray source.
The 2MASS Ks-band magnitude of the NIR counterpart to the X-ray source.