Table information for 'alerce_tap.ztf_detection'

General

Table Description:

Individual detections from ZTF difference imaging, including PSF and aperture photometry, Real/Bogus quality scores, corrected magnitudes accounting for reference flux, and flags indicating image quality and photometric reliability.

This table is available for ADQL queries and through the TAP endpoint.

Resource Description:

Multi-survey astronomical object catalog containing astrometric and statistical information from multiple surveys. This table provides aggregated properties for astronomical objects including position, detection statistics, and temporal coverage.

For a list of all services and tables belonging to this table's resource, see Information on resource 'ALeRCE Multi-Survey Object Catalog'

Citing this table

To cite the table as such, we suggest the following BibTeX entry:

@MISC{vo:alerce_tap_ztf_d,
  year=2026,
  title={{ZTF} Detections},
  author={{ALeRCE} Team},
  url={http://tap.alerce.online/tableinfo/alerce_tap.ztf_detection},
  howpublished={{VO} resource provided by the {ALeRCE} {TAP} service}
}

Columns

Sorted by DB column index. [Sort alphabetically]

NameTable Head DescriptionUnitUCD
oid Oid Unique identifier for this object N/A meta.id;src
sid Sid Survey identifier N/A meta.id
measurement_id Measurement_id Unique identifier for the subtraction candidate (candid from ZTF) N/A meta.id
pid Pid Processing ID for image N/A meta.id
diffmaglim Diffmaglim 5-sigma magnitude limit in difference image based on PSF-fit photometry mag phot.mag;stat.min
isdiffpos Isdiffpos Difference image sign: 1 => candidate is from positive (science minus reference) subtraction; -1 => candidate is from negative (reference minus science) subtraction N/A meta.code
nid Nid Night ID N/A meta.id
magpsf Magpsf Magnitude from PSF-fit photometry mag phot.mag
sigmapsf Sigmapsf 1-sigma uncertainty in magpsf mag stat.error;phot.mag
magap Magap Aperture magnitude using 8 pixel diameter aperture mag phot.mag
sigmagap Sigmagap 1-sigma uncertainty in magap mag stat.error;phot.mag
distnr Distnr Distance to nearest source in reference image PSF-catalog within 30 arcsec arcsec pos.angDistance
rb Rb RealBogus quality score from machine learning classifier, range 0 to 1 where closer to 1 is more reliable N/A stat.probability
rbversion Rbversion Version of RealBogus model/classifier used to assign rb quality score N/A meta.version
drb Drb RealBogus quality score from Deep-Learning-based classifier, range 0 to 1 where closer to 1 is more reliable N/A stat.probability
drbversion Drbversion Version of Deep-Learning-based classifier model used to assign drb quality score N/A meta.version
magapbig Magapbig Aperture magnitude using 18 pixel diameter aperture mag phot.mag
sigmagapbig Sigmagapbig 1-sigma uncertainty in magapbig mag stat.error;phot.mag
rfid Rfid Processing ID for reference image to facilitate archive retrieval N/A meta.id
magpsf_corr Magpsf_corr Corrected PSF magnitude accounting for flux in reference image mag phot.mag;arith.corrected
sigmapsf_corr Sigmapsf_corr Error of the corrected PSF magnitude assuming no contribution from an extended component mag stat.error;phot.mag;arith.corrected
sigmapsf_corr_ext Sigmapsf_corr_ext Error of the corrected PSF magnitude assuming a contribution from an extended component mag stat.error;phot.mag
corrected Corrected Whether the corrected photometry was applied (True if source present in reference image within 1.4 arcsec) N/A meta.code.qual
dubious Dubious Whether the corrected photometry should be flagged as dubious due to inconsistencies N/A meta.code.qual
parent_candid Parent_candid Parent candidate ID if alert coming from previous candidate history (null if from main alert) N/A meta.id
has_stamp Has_stamp Whether the detection has an associated image stamp triplet (when parent_candid is null) N/A meta.code
created_date Created_date Date record was created N/A time.creation

Columns that are parts of indices are marked like this.

VOResource

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