DiaSource
Properties of transient-object detections on the single-epoch difference images.
Columns
| name | datatype | description | unit | nullable | ivoa:ucd | length |
|---|---|---|---|---|---|---|
| diaSourceId | long | Unique identifier of this DiaSource. | false | meta.id;obs.image | ||
| visit | long | Id of the visit where this diaSource was measured. | false | meta.id;obs.image | ||
| detector | short | Id of the detector where this diaSource was measured. | false | meta.id;obs.image | ||
| diaObjectId | long | Id of the diaObject this source was associated with, if any. If not, it is set to 0 | false | meta.id;src | ||
| ssObjectId | long | Id of the ssObject this source was associated with, if any. If not, it is set to 0 | false | meta.id;src | ||
| parentDiaSourceId | long | Id of the parent diaSource this diaSource has been deblended from, if any. | false | meta.id;src | ||
| midpointMjdTai | double | Effective mid-visit time for this diaSource, expressed as Modified Julian Date, International Atomic Time. | d | false | time.epoch | |
| ra | double | Right ascension coordinate of the center of this diaSource. | deg | false | pos.eq.ra;meta.main | |
| dec | double | Declination coordinate of the center of this diaSource. | deg | false | pos.eq.dec;meta.main | |
| raErr | float | Angular error in right ascension (∂RA*cos(Dec)). | deg | true | stat.error;pos.eq.ra | |
| decErr | float | Error in declination. | deg | true | stat.error;pos.eq.dec | |
| ra_dec_Cov | float | Covariance between right ascension (RA*cos(Dec)) and declination. | deg**2 | true | stat.covariance;pos.eq.ra;pos.eq.dec | |
| x | double | Unweighted first moment centroid, overall centroid. | pixel | false | pos.cartesian.x | |
| xErr | float | 1-sigma uncertainty on x position. | pixel | true | stat.error;pos.cartesian.x | |
| y | double | Unweighted first moment centroid, overall centroid. | pixel | false | pos.cartesian.y | |
| yErr | float | 1-sigma uncertainty on y position. | pixel | true | stat.error;pos.cartesian.y | |
| centroid_flag | boolean | General centroid algorithm failure flag; set if anything went wrong when fitting the centroid. Another centroid flag field should also be set to provide more information. | false | |||
| apFlux | float | Flux in a 12 pixel radius aperture on the difference image. | nJy | true | phot.flux | |
| apFluxErr | float | Estimated uncertainty of apFlux. | nJy | true | stat.error;phot.flux | |
| apFlux_flag | boolean | General aperture flux algorithm failure flag; set if anything went wrong when measuring aperture fluxes. Another apFlux flag field should also be set to provide more information. | false | |||
| apFlux_flag_apertureTruncated | boolean | Aperture did not fit within measurement image. | false | |||
| isNegative | boolean | Source was detected as significantly negative. | false | |||
| snr | double | The signal-to-noise ratio at which this source was detected in the difference image. | true | stat.snr | ||
| psfFlux | float | Flux for Point Source model. Note this actually measures the flux difference between the template and the visit image. | nJy | true | phot.flux | |
| psfFluxErr | float | Uncertainty of psfFlux. | nJy | true | stat.error;phot.flux | |
| psfChi2 | float | Chi^2 statistic of the point source model fit. | true | stat.fit.chi2 | ||
| psfNdata | int | The number of data points (pixels) used to fit the point source model. | pixel | false | ||
| psfFlux_flag | boolean | Failure to derive linear least-squares fit of psf model. Another psfFlux flag field should also be set to provide more information. | false | |||
| psfFlux_flag_edge | boolean | Object was too close to the edge of the image to use the full PSF model. | false | |||
| psfFlux_flag_noGoodPixels | boolean | Not enough non-rejected pixels in data to attempt the fit. | false | |||
| trailFlux | float | Flux for a trailed source model. Note this actually measures the flux difference between the template and the visit image. | nJy | true | ||
| trailFluxErr | float | Uncertainty of trailFlux. | nJy | true | ||
| trailRa | double | Right ascension coordinate of centroid for trailed source model. | deg | true | pos.eq.ra | |
| trailDec | double | Declination coordinate of centroid for trailed source model. | deg | true | pos.eq.dec | |
| trailLength | double | Maximum likelihood fit of trail length. | arcsec | true | ||
| trailAngle | double | Maximum likelihood fit of the angle between the meridian through the centroid and the trail direction (bearing). | deg | true | ||
| trail_flag_edge | boolean | This flag is set if a trailed source extends onto or past edge pixels. | false | |||
| dipoleMeanFlux | double | Maximum likelihood value for the mean absolute flux of the two lobes for a dipole model. | nJy | true | ||
| dipoleMeanFluxErr | double | Uncertainty of dipoleMeanFlux. | nJy | true | stat.error | |
| dipoleFluxDiff | double | Maximum likelihood value for the difference of absolute fluxes of the two lobes for a dipole model. | nJy | true | ||
| dipoleFluxDiffErr | double | Uncertainty of dipoleFluxDiff. | nJy | true | stat.error | |
| dipoleLength | double | Maximum likelihood value for the lobe separation in dipole model. | arcsec | true | pos.angDistance | |
| dipoleAngle | double | Maximum likelihood fit of the angle between the meridian through the centroid and the dipole direction (bearing, from negative to positive lobe). | deg | true | pos.posAng | |
| dipoleChi2 | double | Chi^2 statistic of the model fit. | true | stat.fit.chi2 | ||
| dipoleNdata | long | The number of data points (pixels) used to fit the model. | false | |||
| scienceFlux | float | Forced photometry flux for a point source model measured on the visit image centered at DiaSource position. | nJy | true | phot.flux | |
| scienceFluxErr | float | Estimated uncertainty of scienceFlux. | nJy | true | stat.error;phot.flux | |
| forced_PsfFlux_flag | boolean | Forced PSF photometry on science image failed. Another forced_PsfFlux flag field should also be set to provide more information. | false | |||
| forced_PsfFlux_flag_edge | boolean | Forced PSF flux on science image was too close to the edge of the image to use the full PSF model. | false | |||
| forced_PsfFlux_flag_noGoodPixels | boolean | Forced PSF flux not enough non-rejected pixels in data to attempt the fit. | false | |||
| templateFlux | float | Forced photometry flux for a point source model measured on the template image centered at the DiaSource position. | nJy | true | phot.flux | |
| templateFluxErr | float | Uncertainty of templateFlux. | nJy | true | stat.error;phot.flux | |
| ixx | double | Adaptive second moment of the source intensity. | nJy.arcsec**2 | true | ||
| iyy | double | Adaptive second moment of the source intensity. | nJy.arcsec**2 | true | ||
| ixy | double | Adaptive second moment of the source intensity. | nJy.arcsec**2 | true | ||
| ixxPSF | double | Adaptive second moment for the PSF. | nJy.arcsec**2 | true | ||
| iyyPSF | double | Adaptive second moment for the PSF. | nJy.arcsec**2 | true | ||
| ixyPSF | double | Adaptive second moment for the PSF. | nJy.arcsec**2 | true | ||
| shape_flag | boolean | General source shape algorithm failure flag; set if anything went wrong when measuring the shape. Another shape flag field should also be set to provide more information. | false | |||
| shape_flag_no_pixels | boolean | No pixels to measure shape. | false | |||
| shape_flag_not_contained | boolean | Center not contained in footprint bounding box. | false | |||
| shape_flag_parent_source | boolean | This source is a parent source; we should only be measuring on deblended children in difference imaging. | false | |||
| extendedness | double | A measure of extendedness, computed by comparing an object's moment-based trace radius to the PSF moments. extendedness = 1 implies a high degree of confidence that the source is extended. extendedness = 0 implies a high degree of confidence that the source is point-like. | true | |||
| reliability | float | Probability (0-1) that the diaSource is astrophysical, derived from a machine learning model. | true | |||
| band | char | Filter band this source was observed with. | true | meta.id;instr.bandpass | 1 | |
| isDipole | boolean | Source well fit by a dipole. | false | |||
| dipoleFitAttempted | boolean | Attempted to fit a dipole model to this source. | false | |||
| timeProcessedMjdTai | double | Time when the image was processed and this DiaSource record was generated, expressed as Modified Julian Date, International Atomic Time. | false | time.epoch | ||
| bboxSize | long | Size of the square bounding box that fully contains the detection footprint. | pixel | false | ||
| pixelFlags | boolean | General pixel flags failure; set if anything went wrong when setting pixels flags from this footprint's mask. This implies that some pixelFlags for this source may be incorrectly set to False. | false | |||
| pixelFlags_bad | boolean | Bad pixel in the DiaSource footprint. | false | |||
| pixelFlags_cr | boolean | Cosmic ray in the DiaSource footprint. | false | |||
| pixelFlags_crCenter | boolean | Cosmic ray in the 3x3 region around the centroid. | false | |||
| pixelFlags_edge | boolean | Some of the source footprint is outside usable exposure region (masked EDGE or centroid off image). | false | |||
| pixelFlags_nodata | boolean | NO_DATA pixel in the source footprint. | false | |||
| pixelFlags_nodataCenter | boolean | NO_DATA pixel in the 3x3 region around the centroid. | false | |||
| pixelFlags_interpolated | boolean | Interpolated pixel in the DiaSource footprint. | false | |||
| pixelFlags_interpolatedCenter | boolean | Interpolated pixel in the 3x3 region around the centroid. | false | |||
| pixelFlags_offimage | boolean | DiaSource center is off image. | false | |||
| pixelFlags_saturated | boolean | Saturated pixel in the DiaSource footprint. | false | |||
| pixelFlags_saturatedCenter | boolean | Saturated pixel in the 3x3 region around the centroid. | false | |||
| pixelFlags_suspect | boolean | DiaSource's footprint includes suspect pixels. | false | |||
| pixelFlags_suspectCenter | boolean | Suspect pixel in the 3x3 region around the centroid. | false | |||
| pixelFlags_streak | boolean | Streak in the DiaSource footprint. | false | |||
| pixelFlags_streakCenter | boolean | Streak in the 3x3 region around the centroid. | false | |||
| pixelFlags_injected | boolean | Injection in the DiaSource footprint. | false | |||
| pixelFlags_injectedCenter | boolean | Injection in the 3x3 region around the centroid. | false | |||
| pixelFlags_injected_template | boolean | Template injection in the DiaSource footprint. | false | |||
| pixelFlags_injected_templateCenter | boolean | Template injection in the 3x3 region around the centroid. | false | |||
| glint_trail | boolean | This flag is set if the source is part of a glint trail. | false |