LMC30DRCXO - LMC 30 Doradus Complex Chandra X-Ray Point Source Catalog
This HEASARC table contains both the primary high-significance X-ray sources as well as some lower-significance tentative X-ray sources. The latter sources should not be considered definitive. A subsequent Chandra observation of this field, with several times the exposure of this observation, will result in a longer, more complete list of point sources than that given in this paper.
A Chandra/ACIS Study of 30 Doradus II. X-ray Point Sources in the Massive Star Cluster R136 and Beyond Townsley L.K., Broos P.S., Feigelson E.D., Garmire G.P., Getman K.V. <Astron. J., 131, 2164-2184 (2006)> =2006AJ....131.2164T
A running X-ray source number in order of increasing J2000.0 Right Ascension.
An alternative name for the X-ray source using the '[TBF2006]' prefix (for Townsley, Broos and Feigelson 2006) and the source number, as recommended by the CDS Dictionary of Nomenclature of Celestial Objects.
The standard Chandra X-ray source designation using the 'CXOU J' prefix and the truncated J2000.0 coordinates of the source (HHMMSS.ss-DDMMSS.s).
The Right Ascension of the X-ray source in the selected equinox. This was given in J2000.0 decimal degrees to a precision of 10-6 degrees in the original tables.
The Declination of the X-ray source in the selected equinox. This was given in J2000.0 decimal degrees to a precision of 10-6 degrees in the original tables.
The Galactic Longitude of the X-ray source.
The Galactic Latitude of the X-ray source.
The formal 1-sigma radial positional uncertainty (not including any systematic uncertainty) based on source counts, as calculated by acis_extract, in arcseconds. See Section 3.1 of the reference paper for a more detailed discussion of the total positional uncertainty.
The off-axis angle of the X-ray source, in arcminutes.
The net full-band (0.5 - 8 keV) extracted source counts.
The 1-sigma error in the net full-band source counts, calculated using Gehrels' (1986, ApJ, 303, 336) equation 7.
The estimated number of background counts in the source extraction region.
The net hard-band (2 - 8 keV) extracted source counts.
The fraction of the PSF used to extract the source counts. Sources are extracted with a 90% PSF fraction unless they are in a crowded region. Thus, a value of less than 90% for the PSF fraction indicates that the source was crowded and that its properties may be influenced by nearby sources.
The photometric significance (signal-to-noise ratio) of the X-ray source, i.e., the ratio of the full-band counts to the error in the counts.
This flag parameter is set to '<' if the probability that the source is a background fluctuation rather than a true point source is an upper limit rather than an actual value.
The (logarithm of the) probability log(PB) that the source is solely a background fluctuation in the full-band counts rather than a true point source. This represents the authors' primary test of source validity. As described in Section 2.1 of the reference paper, this quantity differentiates the 117 sources in the main source catalog (Table 1; those entries in this HEASARC table with source_sample = 'primary') which have values of PB <= 0.003 from the 63 tentative source in Table 2 (those with source_sample = 'tentative') which have final values of PB > 0.003.
This parameter contains a set of flags which can note the presence of various observational anomalies:
g = fractional time that source was on a detector (FRACEXPO) is <0.9 e = source on field edge p = source piled up
This parameter contains a flag which indicates the likelihood that the X-ray source is displaying variability, based on a calculation of the Kolmogorov-Smirnov statistic as first defined in Feigelson & Lawson (2004, ApJ, 614, 267). Notice that no variability test was performed for sources with fewer than 4 total full-band counts, and that no value is reported for sources in chip gaps or on field edges. The flag values are as follows:
a = no evidence for variability b = possibly variable
The effective exposure time of the X-ray source, in seconds, namely the length of time that the source would have to be observed at the Chandra aimpoint in order to collect the same number of counts as were actually obtained in the observation as performed.
The estimated background-corrected median energy of the X-ray source in the full spectral band, in keV (see Section 3.1 of the reference paper for more details).
The angular separation between the Chandra source and its counterpart, using a hierarchy of matching catalogs, in arcseconds, as follows: if a match from Malumuth and Heap (1994, AJ, 107, 1054 = MH94) was available, then that separation is noted; if there was no MH94 match, then the separation from the 2MASS counterpart is noted; if neither of these matches exists, the separation between the ACIS source and its match from SIMBAD or Vizier is given.
The spectral type of the counterpart star or multiple stellar system, if known, taken from Breysacher et al. (1999, A&AS, 137, 117 = BAT99), Crowther & Dessart (1998, MNRAS, 296, 622), or SIMBAD.
The Breysacher et al. (1999) catalog number of the counterpart star. BAT99 is a catalog of Wolf-Rayet stars in the LMC.
The Parker (1993, AJ, 106, 560 = P93) catalog number of the counterpart star. P93 is a ground-based UBV photometric study of 30 Dor.
The MH94 catalog number of the counterpart star. MH94 is a UBV photometric study of 30 Dor performed with the Hubble Space Telescope.
The X-ray source identification from Portegies Zwart et al. (2002, ApJ, 574, 762 = PPL02)
The Right Ascension (J2000) of the 2MASS counterpart, in decimal degrees.
The Declination (J2000) of the 2MASS counterpart, in decimal degrees.
This field contains matches to the Chandra X-ray source from other catalogs, common names for well-known sources, and other notes.
The HEASARC has combined the main list of primary X-ray sources given in Table 1 of the reference paper with the list of tentative sources given in Table 2 of the same. In order to clearly identify which table an entry was taken from, the HEASARC has created this parameter which is set to 'primary' for entries from Table 1 and to 'tentative' for entries from Table 2.
The HEASARC Browse object classification based on the value of the spect_type parameter, when the latter is populated.