CCD_HDR/CAT/PSF extension is present for each CCD present in the exposure. For most exposures, this is 62. Only S29 is shown in the data model for clarity. In addition to the true exposures, one CCD per exposure is reprocessed after injected sythetic sources. All of the same extensions are present for that injected CCD under the name CCDI. One further extension is saved for the injected CCD to record the ground truth values for the synthetic injections.
EXPOSURE_NAME.cat.fits, where the EXPOSURE_NAME is the name of the ooi file being processed.
Header that is a direct copy of the header for the exposure file from which this catalogue was generated. See ooi model.
Nearly identical copy of the CCD header for the exposure file from which this catalogue was generated. See ooi model. Only rows added by crowdsource are shown here.
| Key | Value | Unit | Comment |
|---|---|---|---|
| GAINCRWD | 3.735677480697632 | e-/ADU | emperical gain (counts times inverse variance) |
| SKYCRWD | 293.1651611328125 | ADU | median sky level across CCD |
| FWHMCRWD | 5.838581562042236 | pixels | median full-width at half-maximum of PSF for all detections in the CCD |
Parameters for a PSF model fit to this CCD of the exposure file. Parameters characterize linear variation of both a Moffat profile and freely fit core model across the CCD coordinates.
| Name | Type | Unit | Description |
|---|---|---|---|
| OFFSET | float32[2] | [DEFUNCT] always (0,0) | |
| STAMP | float32[511,511,2,2] | Full PSF model sampled at the largest grid size (511x511 pixels) at each of the corners of the CCD (as indexed by AXIS 3 and 4) | |
| CONVPARAM | float32[13] | Convolutional parameters for Moffat model and their linear variation (FWHM, dFWHMx, dFWHMy, yy, dyy_x, dyy_y, dxy, dxy_x, dxy_y, norm, unused, unused, unused) | |
| RESPARAM | float32[9,9,3] | Residual model freely fit to the 9x9 pixels of the PSF core. Model varies linearly over the CCD chip so AXIS=3 encodes the constant, dx, and dy parameters. |
Output catalogue from crowdsource processing of a given CCD in the exposure
| Name | Type | Unit | Description |
|---|---|---|---|
| X | float64 | pixels | x coordinate |
| Y | float64 | pixels | y coordinate |
| FLUX | float32 | ADU | raw flux |
| PASSNO | float64 | iteration at which source was found | |
| DX | float32 | pixels | x uncertainty |
| DY | float32 | pixels | y uncertainty |
| DFLUX | float32 | ADU | flux uncertainty (statistical only) |
| QF | float32 | "quality factor" based on PSF-weighted fraction of pixels contributing to the detection. 0 < qf <1 ranges bad < qf < good | |
| RCHI2 | float32 | average \(\chi^2\) per pixel, weighted by PSF | |
| FRACFLUX | float32 | fraction of flux in this object's PSF that comes from this object | |
| FLUXLBS | float32 | [DEFUNCT] flux with attempt at local background subtraction (Backwards compatability only) | |
| DFLUXLBS | float32 | [DEFUNCT] fluxlbs uncertainty (Backwards compatability only) | |
| FWHM | float32 | pixels | full-width at half-maximum of PSF |
| SPREAD_MODEL | float32 | sextractor-like spread_model; positive means the source is broader than a PSF | |
| DSPREAD_MODEL | float32 | uncertainty in sextractor spread_model | |
| FLUXISO | float32 | ADU | flux derived from linear least squares fit to neighbor-subtracted image; significant difference from ordinary flux indicates a convergence issue |
| XISO | float64 | pixels | x coordinate derived from linear least squares fit to neighbor-subtracted image; significant difference from ordinary x indicates a convergence issue |
| YISO | float64 | pixels | y coordinate derived from linear least squares fit to neighbor-subtracted image; significant difference from ordinary y indicates a convergence issue |
| FLAGS | int32 | DECam Community Pipeline flags at central pixel from upstream image processing | |
| SKY | float32 | ADU | sky level at central pixel |
| RA | float64 | degree | right ascension |
| DEC | float64 | degree | declination |
| DECAPSID | int64 | unique object id (internal to each data release) | |
| GAIN | float32 | e-/ADU | emperical gain (counts times inverse variance) |
| PRN | float32 | probability central pixel in "nebulosity" class | |
| PRL | float32 | probability central pixel in "light nebulosity" class | |
| PRR | float32 | probability central pixel in "regular" class | |
| PRE | float32 | probability central pixel in "error" class |
Catalogue of ground truth values for synthetic sources injected into the CCD specified in the extension name to obtain CCDI.
| Name | Type | Unit | Description |
|---|---|---|---|
| X | float64 | pixels | x coordinate |
| Y | float64 | pixels | y coordinate |
| FLUX | float64 | ADU | flux (sum over 59x59 pixel region of noisy draw) |
| FLUXFULL | float64 | ADU | flux (sum over 511x511 pixel region of noisy draw) |
| PSFWT_FLUX | float64 | ADU | PSF-weigted flux (of noisy draw over 511x511 pixel region) |
| AMP | float64 | ADU | ground truth flux before noise and PSF truncation |
An example cat catalogue file is linked here: c4d_190503_101550_ooi_g_v1.cat.fits