Variability (34 columns)

CHI2PROB (Double): The χ² probability (based on the null hypothesis) that the time series of the source, as detected by any of the cameras, can be explained by a constant flux. The minimum value of the available camera probabilities (CHI2PROB) is given. The Pearson's approximation to χ² for Poissonian data was used, in which the model is used as the estimator of its own variance (see the documentation of ekstest for a more detailed description). If more than one exposure (that is, time series) is available for this source the smallest value of probability was used. See 2XMM UG Sec. 3.1.4 for more details but note also changes described in 3XMM UG 3.6.
FVAR (Double) SAS task ekstest: The fractional RMS variability amplitude (deriving from the normalised excess variance) measured in the timeseries of the detection. Where multiple exposures exist, it is for the one giving the largest probability of variability (CHI2PROB). This quantity provides a measure of the amplitude of variability in the timeseries, above purely statistical fluctuations. See Sec. 3.9 for more details.
FVARERR (Double) SAS task ekstest: The error on the fractional RMS variability amplitude for the timeseries of the detection (PN_FVAR). See Sec. 3.9 for more details.
VAR_FLAG (Boolean): The flag is set to True if this source was detected as variable (χ² probability < 1E-5, see CHI2PROB) in at least one exposure (see 2XMM UG Sec. 3.2.8). Note that where a timeseries is not available or insufficient points are left in the timeseries after applying background flare GTIs, the value is set to NULL or Undefined
VAR_CHI_b (Double): The reduced chi-squared of the inter-observation variability in the full (0.2-12.0) or sub-bands, supposing a constant flux. When no band is indicated, it is the full band that is used.
VAR_PROB_b (Double): The probability that the inter-observation variability in the full (0.2-12.0) or sub-bands is consistent with 0. When no band is indicated, it is the full band that is used.
FRATIO_b (Double): Maximum inter-observation flux ratio in the full (0.2-12.0) or sub-bands. When no band is indicated, it is the full band that is used.
FRATIO_b_ERR (Double): 1 σ error on the maximum inter-observation flux ratio in the full (0.2-12.0) or sub-bands. When no band is indicated, it is the full band that is used.
FLUXVAR_b (Double): Maximum inter-observation flux ratio in the full (0.2-12.0) or sub-bands in terms of sigma. When no band is indicated, it is the full band that is used.