Table information for 'ztf.object'

General

Table Description:

Main catalog of astronomical objects observed by ZTF. Each record corresponds to a unique transient or variable source with aggregated position, detection counts, photometric color statistics, and temporal coverage.

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

Resource Description:

Legacy ZTF astronomical catalog containing objects, detections, photometric measurements, classifications, and cross-matches from the Zwicky Transient Facility (ZTF) survey, as processed by the ALeRCE broker pipeline.

For a list of all services and tables belonging to this table's resource, see Information on resource 'ALeRCE ZTF Legacy Catalog'

Citing this table

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

@MISC{vo:ztf_object,
  year=2026,
  title={{ZTF} Object table},
  author={{ALeRCE} Team},
  url={http://tap.alerce.online/tableinfo/ztf.object},
  howpublished={{VO} resource provided by the {ALeRCE} {TAP} service}
}

Columns

Sorted by DB column index. [Sort alphabetically]

NameTable Head DescriptionUnitUCD
oid Oid Unique object identifier N/A meta.id;src
ndethist Ndethist Number of spatially-coincident detections going back to beginning of survey; only detections on the same field and readout-channel ID counted, down to S/N~3 N/A meta.number;obs
ncovhist Ncovhist Number of times the object position fell on any field and readout-channel going back to beginning of survey N/A meta.number;obs
mjdstarthist Mjdstarthist Earliest Modified Julian Date corresponding to ndethist d time.start
mjdendhist Mjdendhist Latest Modified Julian Date corresponding to ndethist d time.end
corrected Corrected Whether the corrected light curve was computed and can be used N/A meta.code.qual
stellar Stellar Whether the object is classified as stellar-like (unresolved source) based on PS1 and ZTF reference image properties N/A src.class.starGalaxy
ndet Ndet Total number of detections N/A meta.number;src
g_r_max G_r_max Maximum g-r color (difference between minimum g and r band magnitudes) N/A phot.color;stat.max
g_r_max_corr G_r_max_corr Maximum g-r color using corrected magnitudes N/A phot.color;stat.max
g_r_mean G_r_mean Mean g-r color (difference between mean g and r band magnitudes) N/A phot.color;stat.mean
g_r_mean_corr G_r_mean_corr Mean g-r color using corrected magnitudes N/A phot.color;stat.mean
meanra Meanra Mean right ascension (ICRS) deg pos.eq.ra;meta.main
meandec Meandec Mean declination (ICRS) deg pos.eq.dec;meta.main
sigmara Sigmara Standard deviation of right ascension deg stat.error;pos.eq.ra
sigmadec Sigmadec Standard deviation of declination deg stat.error;pos.eq.dec
deltajd Deltajd Time span between first and last observation in Julian days d time.interval
firstmjd Firstmjd Modified Julian Date of first detection d time.start;obs
lastmjd Lastmjd Modified Julian Date of last detection d time.end;obs
step_id_corr Step_id_corr Step identifier for the photometric correction pipeline version N/A meta.id
diffpos Diffpos Difference image positivity flag N/A meta.code.qual
reference_change Reference_change Flag indicating a reference image change occurred during the object history N/A meta.code.qual

Columns that are parts of indices are marked like this.

VOResource

VO nerds may sometimes need VOResource XML for this table.