Filter the ZTF object database
The form below is a builder for SQL SELECT queries on the ZTF database of objects. There are three tables that can be joined in SELECT queries (only SELECT queries are allowed). See examples below. The tables are:
- objects: The astrophysical objects which consist of a series of candidates (aka detections). The object has a light curve, the candidate has a single magnitude and date.
- sherlock_crossmatches: Information about each object derived from multiple catalogs by the Sherlock software. The crossmatches have a rank 1,2,3... where 1 is considered most likely.
- candidates: The individual detections provided by ZTF each night. Each is associated with an object, which is a cluster of detections within 1.5 arcsec, and presumed to be an astrophysical object.
For detailed information about the attributes of these three tables, that you can use in the filters : click here.
- The public survey uses two filters: fid=1 (g) and fid=2 (r)
- For each observing field of the survey and each of the g and r filters, ZTF will only issue candidate alerts when it has built up a reference image of that field with that filter, by stacking 15 good images.
- Once that is in place, each fresh image is subtracted from the reference, and any 5-sigma difference generates a candidate alert.
- When a candidate is within 1.5 arcseconds of a previous candidate, it gets the same objectId. Thus a light curve can be obtained from all the candidates that have a given objectId.
- More details of the processing pipeline are available here.
- Further cuts can be made to remove spurious candidates, using the "drb" attribute of each candidate: the range is 0 to 1 where closer to 1 is more reliable.
- If you would like to learn the SQL language, this is a good resource.
(If you would like to create your own stored filters, you should be signed in. See links at top left.)
Contributed Stored Filters
Stored filters created and made public are listed below. Click on the name of the filter to push it into the area above.| Name | Owner | Description | Query |
|---|---|---|---|
| SN-like candidates in last 14 days Detail Stream: 42SN-likecandidatesinlast14days |
Stephen Smartt | SN-like candidates (Sherlock classifications SN, NT and orphans). Rejects Pan-STARRS star matches |
objects.objectId, objects.ramean, objects.decmean, objects.jdmin - 2400000.5 AS mjdmin, objects.jdmax - 2400000.5 AS mjdmax, objects.magrmin, objects.latestrmag, sherlock_classifications.classification, IF(objects.distpsnr1 < 2 AND objects.sgscore1 > 0.49, "Within 2arcsec of PS1 star", "Not Near PS1 star") score---- objects, sherlock_classifications---- objects.objectId = objects.objectId AND
objects.primaryId = sherlock_classifications.transient_object_id AND
objects.jdmax > JDNOW() - 14.00000 AND
sherlock_classifications.classification NOT IN ("VS" , "AGN", "CV", "BS") AND
objects.ncand > 3 AND
objects.latestgmag < 20 AND
objects.ncandgp > 1
ORDER BY score , mjdmin DESC
|
| All nuclear transients and TDE candidates Detail |
Stephen Smartt | Near core of inactive catalogued galaxies (within 1"), flags Pan-STARRS stellar matches to let user judge star/galaxy separation. Objects discovered in last 14 days. |
objects.objectId, objects.ramean, objects.decmean, objects.jdmin - 2400000.5 AS mjdmin, objects.jdmax - 2400000.5 AS mjdmax, objects.magrmin, objects.latestrmag, sherlock_classifications.classification, IF(objects.distpsnr1 < 2 AND objects.sgscore1 > 0.49, "Within 2arcsec of PS1 star", "Not Near PS1 star") score---- objects, sherlock_classifications---- objects.objectId = objects.objectId AND
objects.primaryId = sherlock_classifications.transient_object_id AND
objects.jdmax > JDNOW() - 14.00000 AND
sherlock_classifications.classification IN ("NT") AND
objects.ncand > 3 AND
objects.latestgmag < 20 AND
objects.ncandgp > 1
ORDER BY score , mjdmin DESC
|
| An Asteroid"s Tail Detail Stream: inactive |
Ken Smith | Check ZTF detections for active asteroid (6478) Gault |
objectId, jd-2400000.5 as mjd, ssnamenr---- candidates---- ssnamenr = "6478" |
| SN-like candidates Detail Stream: inactive |
Stephen Smartt | SN-like candidates (Sherlock classifications SN, NT and orphans), discovered within the last 3 days. Also rejects Pan-STARRS star matches. |
objects.objectId,
objects.ramean,
objects.decmean,
objects.jdmin - 2400000.5 AS mjdmin,
objects.jdmax - 2400000.5 AS mjdmax,
objects.magrmin,
objects.latestrmag,
sherlock_classifications.classification,
IF(candidates.distpsnr1 < 2 AND candidates.sgscore1 > 0.49, "Within 2arcsec of PS1 star", "Not Near PS1 star") score
----
objects,candidates,sherlock_classifications---- sherlock_classifications.classification NOT IN ("VS" , "AGN", "CV", "BS")
AND objects.ncand > 3
AND candidates.objectId = objects.objectId
AND candidates.magpsf < 20
AND candidates.rb >= 0.75
AND candidates.nbad = 0
AND candidates.isdiffpos = "t"
AND candidates.fwhm <= 5
AND ABS(candidates.magdiff) <= 0.1
AND candidates.elong <= 1.2
ORDER BY score , mjdmin DESC
|
| Milliquas quasars Detail Stream: 2Milliquasquasars |
Roy Williams | Finds all ZTF objects crossmatched with the Milliquas quasar catalog. |
objects.objectId, objects.ncandgp---- objects,sherlock_crossmatches---- sherlock_crossmatches.catalogue_view_id = 41 ORDER BY objects.ncandgp DESC |
| TNS crossmatch Detail Stream: 2TNScrossmatch |
Roy Williams | This query finds all Lasair objects that are in the <a href=https://wis-tns.weizmann.ac.il/>Transient Name Server</a>, meaning they have a comment that includes the string 'TNS'. The most recent are first. |
objects.objectId, comments.time, comments.content---- objects, comments---- comments.content LIKE '%TNS%' ORDER BY comments.time DESC |
| Outburst AMCanVen Detail Stream: 2OutburstAMCanVen |
Roy Williams | Outburst from moving averages, and watchlist of AMCanVen |
objects.objectId, objects.ncandgp, watchlist_hits.name, jdnow()- objects.jdmax---- objects, watchlist:58---- (-objects.latest_dc_mag_g02 > -objects.latest_dc_mag_g28 + 0.5) and (-objects.latest_dc_mag_r02 > -objects.latest_dc_mag_r28 + 0.5) |
| SN Candidates for MCARG Detail Stream: 150SNCandidatesforMCARG |
Chris Duston | Using Mag < 18, restricting to "SN"-classified, still getting brighter, and including basic observable information for Australia/Spain/NM. |
objects.objectId, objects.ramean, objects.decmean, objects.jdmin - 2400000.5 AS mjdmin, objects.jdmax - 2400000.5 AS mjdmax, objects.magrmin, objects.latestrmag, sherlock_classifications.classification, IF(objects.distpsnr1 < 2 AND objects.sgscore1 > 0.49, "Within 2arcsec of PS1 star", "Not Near PS1 star") score---- objects, sherlock_classifications---- objects.objectId = objects.objectId AND
objects.primaryId = sherlock_classifications.transient_object_id AND
objects.jdmax > JDNOW() - 14.00000 AND
sherlock_classifications.classification NOT IN ("VS" , "AGN", "CV", "BS", "NT", "UNCLEAR") AND
objects.ncand > 3 AND
objects.latestrmag < 18 AND
objects.latestrmag <= objects.magrmin AND
objects.ncandgp > 1 AND
objects.decmean > -32 AND
objects.decmean < 39 AND
objects.ramean > 20 AND
objects.ramean < 160
ORDER BY latestrmag , score , mjdmin DESC
|
| bright stars Detail Stream: 2brightstars |
Roy Williams | bright stars |
objects.objectId, objects.latestrmag, jdnow()-objects.jdmax as since---- objects---- objects.latestrmag < 12 |
| SN-likethings Detail Stream: 218SN-likethings |
Rafia Omer |
objects.objectId, JDNOW() - 2400000.5 as mjdnow, objects.jdmin - 2400000.5 AS mjdmin, objects.jdmax - 2400000.5 AS mjdmax, objects.magrmin, objects.latestrmag, sherlock_classifications.classification, IF(objects.distpsnr1 < 2 AND objects.sgscore1 > 0.49, "Within 2arcsec of PS1 star", "Not Near PS1 star") score---- objects, sherlock_classifications---- sherlock_classifications.classification IN ( "SN" , "ORPHAN" , "NT") AND objects.ncand > 2 AND objects.ncandgp > 2 |
|
| SGLF TNS discovery reports Detail Stream: inactive |
Ismael Perez-Fournon | Possible SNe reported to TNS by SGLF (Supernovae and Gravitational Lenses Follow up) project |
objects.objectId, comments.content, objects.ramean, objects.decmean, objects.jdmin - 2400000.5 AS mjdmin, objects.jdmax - 2400000.5 AS mjdmax, objects.magrmin, objects.latestrmag, sherlock_classifications.classification, IF(objects.distpsnr1 < 2 AND objects.sgscore1 > 0.49, "Within 2arcsec of PS1 star", "Not Near PS1 star") score---- objects, comments, sherlock_classifications---- comments.content LIKE '%SGLF%' ORDER BY mjdmin DESC |
| AMCVn Detail Stream: 104AMCVn |
Gavin Ramsay | AMCVns |
objects.objectId---- objects, watchlist:128---- (-objects.latest_dc_mag_g02 > -objects.latest_dc_mag_g28 + 0.5) and (-objects.latest_dc_mag_r02 > -objects.latest_dc_mag_r28 + 0.5) |
| TDE-candidates Detail Stream: 23TDE-candidates |
Matt Nicholl |
DISTINCT objects.objectId, ROUND(objects.maggmean - objects.magrmean,2) as g_minus_r_mean, ROUND(objects.latestgmag - objects.latestrmag,2) as g_minus_r_latest, objects.latestgmag as g, objects.latestrmag as r, ROUND(objects.jdmin - 2400000.5 ,1) as disc_mjd, ROUND(objects.jdmax - 2400000.5 ,1) as latest_mjd, objects.ncandgp as N_obs, IF(ABS(objects.latestgmag - objects.maggmin) < 0.2 AND objects.latestgmag <= objects.maggmean AND ABS(objects.latestrmag - objects.magrmin) < 0.2 AND objects.latestrmag <= objects.magrmean, "rising/peak", "") rising, IF(objects.latestgmag > objects.maggmin + 0.2 OR objects.latestrmag > objects.magrmin + 0.2, "fading", "") fading, objects.sherlock_classification as sherlock, ROUND(sherlock_crossmatches.separationArcsec,2) as offset, objects.maggmin as g_max, objects.magrmin as r_max, comments.content as TNS, objects.sgscore1 as sg_score, objects.sgmag1 as g_host, objects.srmag1 as r_host, objects.ramean as ra, objects.decmean as decl---- objects, comments, sherlock_crossmatches---- objects.ncand > 2 AND objects.ncand - objects.ncandgp < 3 AND objects.sherlock_classification = 'NT' AND sherlock_crossmatches.separationArcsec < 1.0 AND (objects.maggmean - objects.magrmean < 0.05 OR objects.latestgmag - objects.latestrmag < 0.05) AND (objects.latestrmag < 20.0 OR objects.latestgmag < 20.0) AND (objects.glatmean > 10 OR objects.glatmean < -10) AND objects.sgmag1 - objects.srmag1 > 0 AND comments.content NOT LIKE '%Classified as a SN%' ORDER BY objects.jdmax DESC |
|
| TDE-candidates-E+A Detail Stream: 23TDE-candidates-EA |
Matt Nicholl | Same as TDE-candidate query but cross-matched with E+A galaxy watchlist |
DISTINCT objects.objectId, ROUND(objects.maggmean - objects.magrmean,2) as g_minus_r_mean, ROUND(objects.latestgmag - objects.latestrmag,2) as g_minus_r_latest, objects.latestgmag as g, objects.latestrmag as r, ROUND(objects.jdmin - 2400000.5 ,1) as disc_mjd, ROUND(objects.jdmax - 2400000.5 ,1) as latest_mjd, objects.ncandgp as N_obs, IF(ABS(objects.latestgmag - objects.maggmin) < 0.2 AND objects.latestgmag <= objects.maggmean AND ABS(objects.latestrmag - objects.magrmin) < 0.2 AND objects.latestrmag <= objects.magrmean, "rising/peak", "") rising, IF(objects.latestgmag > objects.maggmin + 0.2 OR objects.latestrmag > objects.magrmin + 0.2, "fading", "") fading, objects.sherlock_classification as sherlock, ROUND(sherlock_crossmatches.separationArcsec,2) as offset, objects.maggmin as g_max, objects.magrmin as r_max, comments.content as TNS, objects.sgscore1 as sg_score, objects.sgmag1 as g_host, objects.srmag1 as r_host, objects.ramean as ra, objects.decmean as decl---- objects, comments, sherlock_crossmatches, watchlist:269---- objects.ncand > 2 AND objects.ncand - objects.ncandgp < 3 AND objects.sherlock_classification = 'NT' AND sherlock_crossmatches.separationArcsec < 1.0 AND (objects.maggmean - objects.magrmean < 0.05 OR objects.latestgmag - objects.latestrmag < 0.05) AND (objects.latestrmag < 20.0 OR objects.latestgmag < 20.0) AND (objects.glatmean > 10 OR objects.glatmean < -10) AND objects.sgmag1 - objects.srmag1 > 0 AND comments.content NOT LIKE '%Classified as a SN%' ORDER BY objects.jdmax DESC |
| TDE's candidates E+A 2 Detail Stream: 264TDEscandidatesEA2 |
yael dgany | same as the first TDE's -candidates E+A query only with latestr/gmag < 19.0 and without objects.sgmag1 - objects.srmag1 > 0 |
DISTINCT objects.objectId, ROUND(objects.maggmean - objects.magrmean,2) as g_minus_r_mean, ROUND(objects.latestgmag - objects.latestrmag,2) as g_minus_r_latest, objects.latestgmag as g, objects.latestrmag as r, ROUND(objects.jdmin - 2400000.5 ,1) as disc_mjd, ROUND(objects.jdmax - 2400000.5 ,1) as latest_mjd, objects.ncandgp as N_obs, IF(ABS(objects.latestgmag - objects.maggmin) < 0.2 AND objects.latestgmag <= objects.maggmean AND ABS(objects.latestrmag - objects.magrmin) < 0.2 AND objects.latestrmag <= objects.magrmean, "rising/peak", "") rising, IF(objects.latestgmag > objects.maggmin + 0.2 OR objects.latestrmag > objects.magrmin + 0.2, "fading", "") fading, objects.sherlock_classification as sherlock, ROUND(sherlock_crossmatches.separationArcsec,2) as offset, objects.maggmin as g_max, objects.magrmin as r_max, comments.content as TNS, objects.sgscore1 as sg_score, objects.sgmag1 as g_host, objects.srmag1 as r_host, objects.ramean as ra, objects.decmean as decl---- objects, comments, sherlock_crossmatches, watchlist:269---- objects.ncand > 2 AND objects.ncand - objects.ncandgp < 3 AND objects.sherlock_classification = 'NT' AND sherlock_crossmatches.separationArcsec < 1.0 AND (objects.maggmean - objects.magrmean < 0.5) AND (objects.latestrmag < 19.0 OR objects.latestgmag < 19.0) AND (objects.glatmean > 10 OR objects.glatmean < -10) AND comments.content NOT LIKE '%Classified as a SN%' ORDER BY objects.jdmax DESC |