Considering background noise has random sources and sources that are different in nature for the two platforms, one would not expect to find a strong correlation when using noise values in platform comparisons.
The EPA says stationary sources of all types (ranging from power plants, refineries, airports, and large manufacturers to smaller factories, dry cleaners, and gas stations), mobile sources (including both on- and off-road vehicles), and background sources (including natural sources and toxics transported long-range) each contribute about equally to the toxics reported in NATA.
Within a sample of unidentified sources, we try to find candidates for background objects and sources within the Milky Way.
If a receiving water has only one point source discharger, the TMDL is the sum of that point source WLA plus the LAs for any nonpoint sources of pollution and natural background sources, tributaries, or adjacent segments.
And, yes, I use background sources other than The Times.
The authors demonstrate that after initial training, most subjects are able to segregate the foreground sound pattern (one sound source) from the background sound source.
The source, background, and source ARF data may be visualized with plot_data, plot_bkg and plot_arf (or simply the plot command, as shown below).
When the lens and a background source align in a particular fashion, quadruple images will result.
Otherwise, set_bkg_source would be used to set the background source model in the usual way, for simultaneous source and background fitting.
If you would like to fit a background-subtracted source spectrum using a common RMF and ARF for the source and background, or fit source and background spectra simultaneously with proper and distinct RMFs and ARFs (but with one response per model expression, unlike in this thread), refer to the Sherpa thread Simultaneously Fitting Source and Background Spectra.
