ALeRCE - ZTF DB 1.0.0 - Google Sheets

	A	B	C	D	E	F	G	H	I	J	K
1	GAIA (only once per oid)	PS1 (only once per oid)	SS (for every candid with info)	data-quality (for every candid)	non-detection (for all oid, mjd)	reference (only once per oid, rfid)	detection (for all candid)	object (only once per oid)

2
3									ztf-avro-alert
4									ZTF Avro Schemas
5									These documents are for schema v3.3.
6
7									Schema Heirarchy
8									ZTF uses nested schemas to organize the data in the alert packet.
9
10									ztf.alert (defined in alert.avsc) is the top-level namespace. ztf.alert in turn relies on candidate.avsc, prv_candidate.avsc, and cutout.avsc.
11
12									ztf.alert
13									The top-level alert contains the following fields:
14
15									Field	Type	Contents
16									schemavsn	string	schema version used
17									publisher	string	origin of alert packet
18	g	p	ss	q	n	r	d	o	objectId	long	unique identifier for this object
19	g	p	ss	q		r	d		candid	long	unique identifier for the subtraction candidate
20									candidate	ztf.alert.candidate	candidate record
21									prv_candidates	array of ztf.alert.prv_candidate or null	candidate records for 30 days’ past history
22									cutoutScience	ztf.alert.cutout or null	cutout of the science image
23									cutoutTemplate	ztf.alert.cutout or null	cutout of the coadded reference image
24									cutoutDifference	ztf.alert.cutout or null	cutout of the resulting difference image
25									ztf.alert.candidate
26									Field	Type	Contents
27					n		d		jd	double	Observation Julian date at start of exposure [days]
28				q	n	r	d		fid	int	Filter ID (1=g; 2=r; 3=i)
29							d		pid	long	Processing ID for image
30							d		diffmaglim	[float, null], default: null	5-sigma mag limit in difference image based on PSF-fit photometry [mag]
31									pdiffimfilename	[string, null], default: null	filename of positive (sci minus ref) difference image
32									programpi	[string, null], default: null	Principal investigator attached to program ID
33									programid	int	Program ID: encodes either public, collab, or caltech mode
34									candid	long	Candidate ID from operations DB
35							d		isdiffpos	string	t or 1 => candidate is from positive (sci minus ref) subtraction; f or 0 => candidate is from negative (ref minus sci) subtraction
36									tblid	[long, null], default: null	Internal pipeline table extraction ID
37							d		nid	[int, null], default: null	Night ID
38						r			rcid	[int, null], default: null	Readout channel ID [00 .. 63]
39						r			field	[int, null], default: null	ZTF field ID
40				q					xpos	[float, null], default: null	x-image position of candidate [pixels]
41				q					ypos	[float, null], default: null	y-image position of candidate [pixels]
42							d		ra	double	Right Ascension of candidate; J2000 [deg]
43							d		dec	double	Declination of candidate; J2000 [deg]
44							d		magpsf	float	magnitude from PSF-fit photometry [mag]
45							d		sigmapsf	float	1-sigma uncertainty in magpsf [mag]
46				q					chipsf	[float, null], default: null	Reduced chi-square for PSF-fit
47							d		magap	[float, null], default: null	Aperture mag using 8 pixel diameter aperture [mag]
48							d		sigmagap	[float, null], default: null	1-sigma uncertainty in magap [mag]
49							d		distnr	[float, null], default: null	distance to nearest source in reference image PSF-catalog within 30 arcsec [pixels]
50						r			magnr	[float, null], default: null	magnitude of nearest source in reference image PSF-catalog within 30 arcsec [mag]
51						r			sigmagnr	[float, null], default: null	1-sigma uncertainty in magnr within 30 arcsec [mag]
52						r			chinr	[float, null], default: null	DAOPhot chi parameter of nearest source in reference image PSF-catalog within 30 arcsec
53						r			sharpnr	[float, null], default: null	DAOPhot sharp parameter of nearest source in reference image PSF-catalog within 30 arcsec
54				q					sky	[float, null], default: null	Local sky background estimate [DN]
55	redundant								magdiff	[float, null], default: null	Difference: magap - magpsf [mag]
56				q					fwhm	[float, null], default: null	Full Width Half Max assuming a Gaussian core, from SExtractor [pixels]
57				q					classtar	[float, null], default: null	Star/Galaxy classification score from SExtractor
58				q					mindtoedge	[float, null], default: null	Distance to nearest edge in image [pixels]
59	redundant								magfromlim	[float, null], default: null	Difference: diffmaglim - magap [mag]
60				q					seeratio	[float, null], default: null	Ratio: difffwhm / fwhm
61				q					aimage	[float, null], default: null	Windowed profile RMS afloat major axis from SExtractor [pixels]
62				q					bimage	[float, null], default: null	Windowed profile RMS afloat minor axis from SExtractor [pixels]
63				q					aimagerat	[float, null], default: null	Ratio: aimage / fwhm
64				q					bimagerat	[float, null], default: null	Ratio: bimage / fwhm
65	redundant								elong	[float, null], default: null	Ratio: aimage / bimage
66				q					nneg	[int, null], default: null	number of negative pixels in a 5 x 5 pixel stamp
67				q					nbad	[int, null], default: null	number of prior-tagged bad pixels in a 5 x 5 pixel stamp
68							d		rb	[float, null], default: null	RealBogus quality score; range is 0 to 1 where closer to 1 is more reliable
69							d		rbversion	string	version of RealBogus model/classifier used to assign rb quality score
70							d		drb	[float, null], default: null	RealBogus quality score from Deep-Learning-based classifier; range is 0 to 1 where closer to 1 is more reliable
71							d		drbversion	string	version of Deep-Learning-based classifier model used to assign RealBogus (drb) quality score
72			ss						ssdistnr	[float, null], default: null	distance to nearest known solar system object; set to -999.0 if none [arcsec]
73			ss						ssmagnr	[float, null], default: null	magnitude of nearest known solar system object (usually V-band from MPC archive); set to -999.0 if none [mag]
74			ss						ssnamenr	[string, null], default: null	name of nearest known solar system object (from MPC archive); ‘null’ if none
75				q					sumrat	[float, null], default: null	Ratio: sum(pixels) / sum(abs(pixels)) in a 5 x 5 pixel stamp where stamp is first median-filtered to mitigate outliers
76							d		magapbig	[float, null], default: null	Aperture mag using 18 pixel diameter aperture [mag]
77							d		sigmagapbig	[float, null], default: null	1-sigma uncertainty in magapbig [mag]
78						r			ranr	double	Right Ascension of nearest source in reference image PSF-catalog; J2000 [deg]
79						r			decnr	double	Declination of nearest source in reference image PSF-catalog; J2000 [deg]
80								o	ndethist	int	Number of spatially-coincident detections falling within 1.5 arcsec going back to beginning of survey; only detections that fell on the same field and readout-channel ID where the input candidate was observed are counted. All raw detections down to a photometric S/N of ~ 3 are included.
81								o	ncovhist	int	Number of times input candidate position fell on any field and readout-channel going back to beginning of survey
82								o	jdstarthist	[double, null], default: null	Earliest Julian date of epoch corresponding to ndethist [days]
83								o	jdendhist	[double, null], default: null	Latest Julian date of epoch corresponding to ndethist [days]
84				q					scorr	[double, null], default: null	Peak-pixel signal-to-noise ratio in point source matched-filtered detection image
85									tooflag	[int, null], default: 0	1 => candidate is from a Target-of-Opportunity (ToO) exposure; 0 => candidate is from a non-ToO exposure
86		p							objectidps1	[long, null], default: null	Object ID of closest source from PS1 catalog; if exists within 30 arcsec
87		p							sgmag1	[float, null], default: null	g-band PSF magnitude of closest source from PS1 catalog; if exists within 30 arcsec [mag]
88		p							srmag1	[float, null], default: null	r-band PSF magnitude of closest source from PS1 catalog; if exists within 30 arcsec [mag]
89		p							simag1	[float, null], default: null	i-band PSF magnitude of closest source from PS1 catalog; if exists within 30 arcsec [mag]
90		p							szmag1	[float, null], default: null	z-band PSF magnitude of closest source from PS1 catalog; if exists within 30 arcsec [mag]
91		p							sgscore1	[float, null], default: null	Star/Galaxy score of closest source from PS1 catalog 0 <= sgscore <= 1 where closer to 1 implies higher likelihood of being a star
92		p							distpsnr1	[float, null], default: null	Distance of closest source from PS1 catalog; if exists within 30 arcsec [arcsec]
93		p							objectidps2	[long, null], default: null	Object ID of second closest source from PS1 catalog; if exists within 30 arcsec
94		p							sgmag2	[float, null], default: null	g-band PSF magnitude of second closest source from PS1 catalog; if exists within 30 arcsec [mag]
95		p							srmag2	[float, null], default: null	r-band PSF magnitude of second closest source from PS1 catalog; if exists within 30 arcsec [mag]
96		p							simag2	[float, null], default: null	i-band PSF magnitude of second closest source from PS1 catalog; if exists within 30 arcsec [mag]
97		p							szmag2	[float, null], default: null	z-band PSF magnitude of second closest source from PS1 catalog; if exists within 30 arcsec [mag]
98		p							sgscore2	[float, null], default: null	Star/Galaxy score of second closest source from PS1 catalog; if exists within 30 arcsec: 0 <= sgscore <= 1 where closer to 1 implies higher likelihood of being a star
99		p							distpsnr2	[float, null], default: null	Distance to second closest source from PS1 catalog; if exists within 30 arcsec [arcsec]
100		p							objectidps3	[long, null], default: null	Object ID of third closest source from PS1 catalog; if exists within 30 arcsec