Table information for 'alerce_tap.ztf_reference'

General

Table Description:

DO NOT USE - ZTF DATA MIGRATION IN PROGRESS; THIS TABLE MAY BE INCOMPLETE OR INCORRECT.

Information about ZTF reference (template) images used for difference imaging, including properties of the nearest catalog source, temporal coverage of the reference image stack, and field/CCD identifiers.

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_r,
  year=2026,
  title={{ZTF} Reference Images},
  author={{ALeRCE} Team},
  url={http://tap.alerce.online/tableinfo/alerce_tap.ztf_reference},
  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
rfid Rfid Processing ID for reference image to facilitate archive retrieval N/A meta.id
measurement_id Measurement_id Unique identifier for the first detection associated with this reference image N/A meta.id
band Band Filter ID: 1=g, 2=r, 3=i N/A instr.bandpass
rcid Rcid Readout channel ID [00 .. 63] N/A instr.det
field Field ZTF field ID N/A obs.field
magnr Magnr Magnitude of nearest source in reference image PSF-catalog within 30 arcsec mag phot.mag
sigmagnr Sigmagnr 1-sigma uncertainty in magnr within 30 arcsec mag stat.error;phot.mag
chinr Chinr DAOPhot chi parameter of nearest source in reference image PSF-catalog within 30 arcsec N/A stat.fit.chi2
sharpnr Sharpnr DAOPhot sharp parameter of nearest source in reference image PSF-catalog within 30 arcsec (values between -0.13 and 0.1 indicate unresolved sources) N/A stat.value
ranr Ranr Right ascension of nearest source in reference image PSF-catalog, J2000 deg pos.eq.ra;meta.main
decnr Decnr Declination of nearest source in reference image PSF-catalog, J2000 deg pos.eq.dec;meta.main
mjdstartref Mjdstartref Observation Modified Julian Date of earliest exposure used to generate reference image d time.start
mjdendref Mjdendref Observation Modified Julian Date of latest exposure used to generate reference image d time.end
nframesref Nframesref Number of frames (epochal images) used to generate reference image N/A meta.number
created_date Created_date Date record was created N/A time.creation

Columns that are parts of indices are marked like this.

VOResource

VO nerds may sometimes need VOResource XML for this table.