Table 1
Description of the output tables per sky tile.
| Column name | Format(a) | Units | Description |
|---|---|---|---|
| HEALPix index | K | – | Projection of the coordinates into HEALPix map. |
| Counts | J | cts | Extracted counts within the aperture from the science image.(a) |
| Bkg_counts | E | cts | Extracted background counts within the aperture from the background image.(b) |
| Bkg_SourceMap | E | cts | Extracted counts within the aperture from the source-map image.(b) |
| Exposure | E | s | Average exposure time within the circular aperture. |
| Flag_pos | I | – | Close neighbor flag(c). |
| Flux_UL_B | E | erg s−1 cm−2 | Flux upper limit at CL=0.9987 (one-sided) based on column “Bkg_counts”.(d) |
| Flux_UL_S | E | erg s−1 cm−2 | Same as UL_B, but based on the source-map counts (“Bkg_SourceMap”).(d) |
Notes. (a)Format of the columns as defined in https://docs.astropy.Org/en/stable/io/fits/usage/table.html#column-creation. In particular, E denotes a single precision float (32-bit), I a 16-bit integer, J a 32-bit integer, and K a 64-bit integer. (b)Extracted from an aperture defined by an EEF=0.75 of the PSF. (c)Set to 1 if the aperture of a given pixel overlaps with a detected source and 0 in source-free regions, according to the procedure presented in Sect. 3.4. (d)Corrected by the fraction of the PSF (see Eq. (7)). Flux obtained for an absorbed power-law spectral model with a photon index of Γ = 2.0 and a column density of NH = 3 × 1020 cm−2. The header of the FITS file contains the ECF of the absorbed power law model. Thus, the user can multiply the upper flux limit with this factor to recover the upper limit in units of counts per second and apply any other ECF for their preferred spectral model (see Sect. 4).
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