Free Access

Table 2.

PDF models fit to the histogram of the flux measurements.

Model Component N0(a) FmaxPD(b) σlnF(c) ΔTS (d) Δdof (e)
(%) (10−6 cm−2 s−1)
Single log-normal 100 1.56 ± 0.06 0.94 ± 0.03 0 0

Double log-normal A (f) 5.6 ± 1.0 0.066 (fixed) 0.51 (fixed) 180.4 1
B 94.4 ± 1.0 1.82 ± 0.05 0.67 ± 0.02

Triple log-normal X (f) 3.3 ± 1.0 0.066 (fixed) 0.51 (fixed) 233.6 4
Y 31.2 ± 13.0 1.14 ± 0.33 1.07 ± 0.18
Z 65.5 ± 13.9 2.10 ± 0.08 0.45 ± 0.06



The normalization for scaling a component. In each model, the sum of normalizations of all components must be 1.


The flux corresponding to the maximum probability density. It is mathematically equivalent to the exponential of the mean of the flux’s natural logarithm.


The standard deviation of the flux’s natural logarithm.


The natural logarithm of the square of the likelihood ratio of a model compared to the single log-normal. The likelihood function is for a Poisson distribution.


The number of additional parameters (the extra degrees of freedom) of a model compared to the single log-normal.


Components which model the shot-noise fluctuations of the extrapolated IC flux. All of their parameters except normalizations are fixed at values estimated from the photon statistics.

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.