V/154 Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)
The 16th Data Release of the Sloan Digital Sky Surveys.
Ahumada R., Allende Prieto C., Almeida A. et al.
<Astrophys. J. Suppl. Ser., 249, 3 (2020) >
=2020ApJS..249....3A 2020ApJS..249....3A
=2022yCat.5154....0A 2022yCat.5154....0A
ADC_Keywords: Surveys; Photometry, SDSS ; Redshifts
Keywords: Astronomy databases - Optical telescopes - Infrared astronomy -
Redshift surveys - Galactic abundances - Stellar spectral lines -
Stellar properties
Abstract:
This paper documents the 16th data release (DR16) from the Sloan
Digital Sky Surveys (SDSS), the fourth and penultimate from the fourth
phase (SDSS-IV). This is the first release of data from the Southern
Hemisphere survey of the Apache Point Observatory Galactic Evolution
Experiment 2 (APOGEE-2); new data from APOGEE-2 North are also
included. DR16 is also notable as the final data release for the main
cosmological program of the Extended Baryon Oscillation Spectroscopic
Survey (eBOSS), and all raw and reduced spectra from that project are
released here. DR16 also includes all the data from the Time Domain
Spectroscopic Survey and new data from the SPectroscopic
IDentification of ERosita Survey programs, both of which were
co-observed on eBOSS plates. DR16 has no new data from the Mapping
Nearby Galaxies at Apache Point Observatory (MaNGA) survey (or the
MaNGA Stellar Library "MaStar").
Description:
Data Release 16 (DR16) is the fourth data release of the fourth phase
of the Sloan Digital Sky Survey (SDSS-IV). DR16 contains SDSS
observations through August 2018.
The principal changes from previous versions are summarized at
http://www.sdss.org/dr16/whatsnew/
Acknowledging SDSS-IV in publications:
We request that the following be added to the acknowledgment section
of any paper using data from the SDSS-IV.
Funding for the Sloan Digital Sky Survey IV has been provided by the
Alfred P. Sloan Foundation, the U.S. Department of Energy Office of
Science, and the Participating Institutions. SDSS acknowledges support
and resources from the Center for High-Performance Computing at the
University of Utah. The SDSS web site is www.sdss.org.
SDSS is managed by the Astrophysical Research Consortium for the
Participating Institutions of the SDSS Collaboration including the
Brazilian Participation Group, the Carnegie Institution for Science,
Carnegie Mellon University, Center for Astrophysics | Harvard &
Smithsonian (CfA), the Chilean Participation Group, the French
Participation Group, Instituto de Astrofisica de Canarias, The Johns
Hopkins University, Kavli Institute for the Physics and Mathematics of
the Universe (IPMU) / University of Tokyo, the Korean Participation
Group, Lawrence Berkeley National Laboratory, Leibniz Institut fur
Astrophysik Potsdam (AIP), Max-Planck-Institut fur Astronomie (MPIA
Heidelberg), Max-Planck-Institut fur Astrophysik (MPA Garching),
Max-Planck-Institut fur Extraterrestrische Physik (MPE), National
Astronomical Observatories of China, New Mexico State University, New
York University, University of Notre Dame, Observatorio Nacional /
MCTI, The Ohio State University, Pennsylvania State University,
Shanghai Astronomical Observatory, United Kingdom Participation Group,
Universidad Nacional Autonoma de Mexico, University of Arizona,
University of Colorado Boulder, University of Oxford, University of
Portsmouth, University of Utah, University of Virginia, University of
Washington, University of Wisconsin, Vanderbilt University, and Yale
University.
Find out more about how to cite SDSS-IV and earlier phases of SDSS, as
well as a LaTeX template at
http://www.sdss.org/collaboration/citing-sdss/
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
sdss16.sam 1187 1000 *Sample output of the SDSS photometric catalog
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Note on sdss16.sam: a sample close to the point (45,0) is given in "sdss16.sam".
The catalog described here is a subset of the full SDSS catalog
available from http://skyserver.sdss.org/dr16 including tables
"PhotoObjAll", "SpecObjAll", "ProperMotions", "Photoz" and "Field"
with a selection of columns. Column names (labels) frequently differ
from their original names, in which case the original name is added to
the description of the original column.
--------------------------------------------------------------------------------
See also:
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
http://www.sdss.org/dr16/ : SDSS DR16 home page
http://skyserver.sdss.org/dr16/en/home.aspx : SDSS DR16 data access
Byte-by-byte Description of file: sdss16.sam
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- objID SDSS unique object identifier (1)
21- 30 F10.6 deg RAdeg Right Ascension of the object (ICRS)
at Epoch="MJD" (ra)
32- 41 F10.6 deg DEdeg Declination of the object (ICRS)
at Epoch="MJD" (dec)
43- 61 I19 --- fieldID The field this object is in
63 I1 --- mode [1/4] PhotoMode (1=primary, 2=secondary,
3=family, 4=outside)
65 I1 --- class [0/8]? Type of object (3=galaxy, 6=star)
(type) (2)
67 I1 --- clean [0/1] Clean photometry flag (1=clean;
0=unclean)
69- 87 I19 --- flags Photo Object Attribute flags (3)
89- 94 F6.3 mag upmag [4/35]? PSF magnitude in u band
(psfMag_u) (4)
96- 101 F6.3 mag gpmag [3.7/37]? PSF magnitude in g band
(psfMag_g) (4)
103- 108 F6.3 mag rpmag [3.8/36]? PSF magnitude in r band
(psfMag_r) (4)
110- 115 F6.3 mag ipmag [2.6/34]? PSF magnitude in i band
(psfMag_i) (4)
117- 122 F6.3 mag zpmag [3.8/33.3]? PSF magnitude in z band
(psfMag_z) (4)
124- 130 F7.3 mag e_upmag [1.5e-5/100]? Mean error on upmag
(psfMagErr_u) (4)
132- 137 F6.3 mag e_gpmag ? Mean error on gpmag (psfMagErr_g) (4)
139- 145 F7.3 mag e_rpmag ? Mean error on rpmag (psfMagErr_r) (4)
147- 153 F7.3 mag e_ipmag ? Mean error on ipmag (psfMagErr_i) (4)
155- 161 F7.3 mag e_zpmag ? Mean error on zpmag (psfMagErr_z) (4)
163- 168 F6.3 mag uPmag [-0.4/47.2]? Petrosian magnitude in u
band (petroMag_u) (4)
170- 175 F6.3 mag gPmag [3.7/48]? Petrosian magnitude in g band
(petroMag_g) (4)
177- 182 F6.3 mag rPmag [1.3/48.6]? Petrosian magnitude in r band
(petroMag_r) (4)
184- 189 F6.3 mag iPmag [2.6/48.4]? Petrosian magnitude in i band
(petroMag_i) (4)
191- 196 F6.3 mag zPmag [-2.9/45.1]? Petrosian magnitude in z
band (petroMag_z) (4)
198- 204 F7.3 mag e_uPmag [1e-7/100]? Mean error in uPmag
(petroMagErr_u) (4)
206- 212 F7.3 mag e_gPmag [9.1e-9/100]? Mean error in gPmag
(petroMagErr_g) (4)
214- 220 F7.3 mag e_rPmag ? Mean error in rPmag (petroMagErr_r) (4)
222- 228 F7.3 mag e_iPmag ? Mean error in iPmag (petroMagErr_i) (4)
230- 236 F7.3 mag e_zPmag ? Mean error in zPmag (petroMagErr_z) (4)
238- 244 F7.3 arcsec uPrad [1.2e-6/261]? Petrosian radius in u band
(petroRad_u)
246- 252 F7.3 arcsec gPrad [2.3e-6/261]? Petrosian radius in g band
(petroRad_g)
254- 260 F7.3 arcsec rPrad [4.9e-6/260]? Petrosian radius in r band
(petroRad_r)
262- 268 F7.3 arcsec iPrad [2.2e-6/263]? Petrosian radius in i band
(petroRad_i)
270- 276 F7.3 arcsec zPrad [8.3e-7/261]? Petrosian radius in z band
(petroRad_z)
278- 286 F9.3 arcsec e_uPrad [-1000/259]? Mean error in rPrad
(petroRadErr_u)
288- 296 F9.3 arcsec e_gPrad [-1000/259]? Mean error in rPrad
(petroRadErr_g)
298- 306 F9.3 arcsec e_rPrad [-1000/259]? Mean error in rPrad
(petroRadErr_r)
308- 316 F9.3 arcsec e_iPrad [-1000/259]? Mean error in rPrad
(petroRadErr_i)
318- 326 F9.3 arcsec e_zPrad [-1000/257]? Mean error in rPrad
(petroRadErr_z)
328- 334 F7.3 arcsec udVrad [0/257]? De Vaucouleurs fit radius u band
(deVRad_u)
336- 342 F7.3 arcsec gdVrad [0/238]? De Vaucouleurs fit radius g band
(deVRad_g)
344- 350 F7.3 arcsec rdVrad [0/238]? De Vaucouleurs fit radius r band
(deVRad_r)
352- 358 F7.3 arcsec idVrad [0/232]? De Vaucouleurs fit radius i band
(deVRad_i)
360- 366 F7.3 arcsec zdVrad [0/238]? De Vaucouleurs fit radius z band
(deVRad_z)
368- 372 F5.3 --- udVell [0.05/1]? De Vaucouleurs fit b/a u band
(deVAB_u)
374- 378 F5.3 --- gdVell [0.05/1]? De Vaucouleurs fit b/a g band
(deVAB_g)
380- 384 F5.3 --- rdVell [0.05/1]? De Vaucouleurs fit b/a r band
(deVAB_r)
386- 390 F5.3 --- idVell [0.05/1]? De Vaucouleurs fit b/a i band
(deVAB_i)
392- 396 F5.3 --- zdVell [0.05/1]? De Vaucouleurs fit b/a z band
(deVAB_z)
398- 405 F8.1 deg uPA [-10105/271]? Position angle of dVrad in
u band (deVPhi_u)
407- 414 F8.1 deg gPA [-10105/271]? Position angle of dVrad in
g band (deVPhi_g)
416- 423 F8.1 deg rPA [-10105/271]? Position angle of dVrad in
r band (deVPhi_r)
425- 432 F8.1 deg iPA [-10105/271]? Position angle of dVrad in
i band (deVPhi_i)
434- 441 F8.1 deg zPA [-10105/271]? Position angle of dVrad in
z band (deVPhi_z)
443- 461 I19 --- uFlags Detection flags u band (flags_u) (3)
463- 481 I19 --- gFlags Detection flags g band (flags_g) (3)
483- 501 I19 --- rFlags Detection flags r band (flags_r) (3)
503- 521 I19 --- iFlags Detection flags i band (flags_i) (3)
523- 541 I19 --- zFlags Detection flags z band (flags_z) (3)
543 I1 --- uc [0/8]? Phototype in u band
(6=Star ; 3=galaxy) (type_u) (2)
545 I1 --- gc [0/8]? Phototype in i band
(6=Star ; 3=galaxy) (type_g) (2)
547 I1 --- rc [0/8]? Phototype in r band
(6=Star ; 3=galaxy) (type_r) (2)
549 I1 --- ic [0/8]? Phototype in i band
(6=Star ; 3=galaxy) (type_i) (2)
551 I1 --- zc [0/8]? Phototype in z band
(6=Star ; 3=galaxy) (type_z) (2)
553- 555 F3.1 --- us [0/1]? 0=notStar 1=Star in u band
(probPSF_u)
557- 559 F3.1 --- gs [0/1]? 0=notStar 1=Star in g band
(probPSF_g)
561- 563 F3.1 --- rs [0/1]? 0=notStar 1=Star in r band
(probPSF_r)
565- 567 F3.1 --- is [0/1]? 0=notStar 1=Star in i band
(probPSF_i)
569- 571 F3.1 --- zs [0/1]? 0=notStar 1=Star in z band
(probPSF_z)
573- 581 F9.3 arcsec e_RAdeg [0/51703] Mean error on RAdeg (raErr)
583- 591 F9.3 arcsec e_DEdeg [0/22795] Mean error on DEdeg (decErr)
593- 603 F11.2 arcsec uoRA Offset of u position along RA (offsetRa_u)
605- 615 F11.2 arcsec goRA Offset of g position along RA (offsetRa_g)
617- 627 F11.2 arcsec roRA Offset of r position along RA (offsetRa_r)
629- 639 F11.2 arcsec ioRA Offset of i position along RA (offsetRa_i)
641- 651 F11.2 arcsec zoRA Offset of z position along RA (offsetRa_z)
653- 659 F7.2 arcsec uoDE Offset of u position along Dec (offsetDec_u)
661- 667 F7.2 arcsec goDE Offset of g position along Dec (offsetDec_g)
669- 675 F7.2 arcsec roDE Offset of r position along Dec (offsetDec_r)
677- 683 F7.2 arcsec ioDE Offset of i position along Dec (offsetDec_i)
685- 691 F7.2 arcsec zoDE Offset of z position along Dec (offsetDec_z)
693- 711 I19 --- parentID Pointer to parent (if object deblended)
713- 732 A20 --- SpObjID Pointer to the spectrum of object or 0
(specObjID) (6)
734- 739 F6.3 mag umag [4/37.3]? Model magnitude in u filter AB
scale (u) (7)
741- 746 F6.3 mag gmag [3.7/39.6]? Model magnitude in g filter
AB scale (g) (7)
748- 753 F6.3 mag rmag [3.8/40.4]? Model magnitude in r filter
AB scale (r) (7)
755- 760 F6.3 mag imag [2.6/39.5]? Model magnitude in i filter
AB scale (i) (7)
762- 767 F6.3 mag zmag [3.5/37.2]? Model magnitude in z filter
AB scale (z) (7)
769- 776 F8.3 mag e_umag [8.9e-8/3444]? Mean error on umag (err_u)
778- 785 F8.3 mag e_gmag [3.8e-8/5955]? Mean error on gmag (err_g)
787- 793 F7.3 mag e_rmag [5.2e-8/915]? Mean error on rmag (err_r)
795- 801 F7.3 mag e_imag [0/634]? Mean error on imag (err_i)
803- 810 F8.3 mag e_zmag [9.4e-8/3529]? Mean error on zmag (err_z)
812- 815 I4 --- Status [0/4145] Decimal status (resolveStatus) (5)
--------------------------------------------------------------------------------
817- 820 A4 --- spInst ? Spectral instrument used
("SDSS" or "BOSS") (spec_instrument) (6)
822- 846 A25 --- spType ? Source type (spec_sourceType) (6)(8)
848- 855 F8.5 --- zsp [-0.012/7.06]? Spectroscopic final
redshift (when SpObjID>0) (spec_z) (6)
857- 867 F11.5 --- e_zsp [-6/30689]? Mean error on zsp
(negative for bad fit) (spec_zErr) (6)
869- 871 I3 --- f_zsp [0/902]? Zwarning flag
(spec_zWarning) (6)(9)
873- 878 A6 --- spCl ? Spectroscopic class: "GALAXY"; "QSO";
"STAR" (spec_class) (6)
880- 891 A12 --- subCl ? Spectroscopic subclass
(spec_subClass) (6)(10)
893- 899 F7.3 km/s Vdisp [0/850]? Velocity dispersion
(spec_velDisp) (6)
901- 908 F8.3 km/s e_Vdisp [-7/4526]? Mean error on Vdisp
(spec_velDispErr) (6)
910- 917 F8.2 --- spS/N [-1927/132]? Median signal-to-noise over
all good pixels (spec_snMedian) (6)
--------------------------------------------------------------------------------
919 I1 --- M [0/4]? Number of USNO-B objects matched
within 1arcsec (pm_match) (11)
921- 928 F8.2 mas/yr pmRA [-6121/5519]? Proper motion along Right
Ascension (pm_pmRa) (11)
930- 937 F8.2 mas/yr pmDE [-4846/4437]? Proper motion along
Declination (pm_pmDec) (11)
939- 945 F7.2 mas/yr e_pmRA [0/4709]? Mean error on pmRA
(pm_pmRaErr) (11)
947- 953 F7.2 mas/yr e_pmDE [0/4709]? Mean error on pmDE
(pm_pmDecErr) (11)
955- 961 F7.2 mas sigRA [0/8662]? RMS residual of proper motion
fit in RA (pm_sigRa) (11)
963- 970 F8.2 mas sigDE [0/10625]? RMS residual of proper motion
fit in Dec (pm_sigDec) (11)
972 I1 --- N [0/6]? Number of detections used in the
pm fit including SDSS (pm_nFit) (11)
974- 982 F9.1 --- g(O) [-214740/70189]? Magnitude from USNO-B O
plate recalibrated to SDSS g (pm_O) (11)
984- 992 F9.1 --- r(E) ? Magnitude from E plate recalibrated to
SDSS r (pm_E) (11)
994- 1002 F9.1 --- g(J) ? Magnitude from J plate recalibrated to
SDSS g (pm_J) (11)
1004- 1012 F9.1 --- r(F) ? Magnitude from F plate recalibrated to
SDSS r (pm_F) (11)
1014- 1022 F9.1 --- i(N) ? Magnitude from N plate recalibrated to
SDSS i (pm_N) (11)
--------------------------------------------------------------------------------
1024- 1029 F6.4 --- zph [5e-4/1]? Photometric redshift estimated
by robust fit to nearest neighbors in a
reference set (photoz_z) (12)
1031- 1036 F6.4 --- e_zph [0.003/0.3]? Estimated error of the
photometric redshift (photoz_zErr) (12)
1038- 1043 F6.4 --- [0.009/0.9]? Average redshift of the
nearest neighbors; if significantly
different from zph this might be a better
estimate than zph (photoz_nnAvgZ) (12)
1045- 1056 F12.3 --- chi2 [2e-12/6.3e7]? Chi-square value for the
minimum chi-square template fit
(photoz_chisq) (12)
--------------------------------------------------------------------------------
1058 I1 --- Q [1/3] Quality of the observation: 1=bad;
2=barely acceptable; 3=good
(field_quality) (13)
1060- 1069 F10.4 d uMJD Date of observation in u band
(fieldmjdu) (13)
1071- 1080 F10.4 d gMJD Date of observation in g band
(fieldmjdg) (13)
1082- 1091 F10.4 d rMJD Date of observation in r band
(fieldmjdr) (13)
1093- 1102 F10.4 d iMJD Date of observation in i band
(fieldmjdi) (13)
1104- 1113 F10.4 d zMJD Date of observation in z band
(fieldmjdz) (13)
--------------------------------------------------------------------------------
1115- 1138 A24 --- SDSS16 SDSS-DR16 name based on J2000 position;
provided by CDS
1140- 1159 A20 --- SDSS-ID SDSS object identifier
(run-rerun-camcol-field-object) (1)
1161- 1176 A16 --- Sp-ID ? Spectroscopic Plate-MJD-Fiber identifier
(plate-mjd-fiberID)
1178- 1187 F10.4 d MJD Mean observation date
(average calculated by CDS from the uMJD,
gMJD, rMJD, iMJD, zMJD)
--------------------------------------------------------------------------------
Note (1): The SDSS identifier is composed of the 5 numbers run, rerun
(301), camcol (1-6), field (11-1001) and object (1-16000).
The SDSS-ID is written run-rerun-cam-field-obj (5 numbers and 4
dashes).
The objID is also combined from these numbers (the ≪n operator
represents the left shift of n bits, i.e. a multiplication by 2^n):
objID = skyVersion≪59 + rerun≪48 + run≪32 + camcol≪29 + field≪16 + obj
(objID is in the range 1237645876861272065-1237680531356583125).
Note (2): The type (class) is numbered as follows:
0 = Unknown: Object type is not known.
1 = Cosmic-ray track (not used).
2 = Defect (not used)
3 = Galaxy: An extended object composed of many stars and other matter
4 = Ghost: Object created by reflected or refracted light. (not used)
5 = KnownObject: Object came from some other catalog (not yet used)
6 = Star: A a self-luminous gaseous celestial body
7 = Trail: A satellite or asteroid or meteor trail. (not yet used)
8 = Sky: Blank sky spectrogram (no objects in this arcsecond area).
Note (3): flags written in hexadecimal, full description available at
http://skyserver.sdss.org/dr16/en/help/browser/browser.aspx#
&&history=enum+PhotoFlags+E
------------------------------------------------------------------------------
0000000000000001 = CANONICAL_CENTER Measurements used the center in r*
0000000000000002 = BRIGHT Object detected in bright object-finding
0000000000000004 = EDGE Object is too close to edge of frame
0000000000000008 = BLENDED Multiple peaks detected
0000000000000010 = CHILD Product of deblending a BLENDED object.
0000000000000020 = PEAKCENTER Position of peak pixel rather than ML
0000000000000040 = NODEBLEND No deblending attempted on BLENDED object
0000000000000080 = NOPROFILE Radial profile could not be estimated
0000000000000100 = NOPETRO No valid Petrosian radius found
0000000000000200 = MANYPETRO More than one Petrosian radius found.
0000000000000400 = NOPETRO_BIG Petrosian radius beyond radial profile.
0000000000000800 = DEBLENDTOOMANY_PEAKS More than 25 peaks in this object
0000000000001000 = COSMIC_RAY Contains a pixel part of a cosmic ray.
0000000000002000 = MANYR50 More than one 50% light radius.
0000000000004000 = MANYR90 More than one 90% light radius.
0000000000008000 = BAD_RADIAL Some points in radial profile S/N<0
0000000000010000 = INCOMPLETE_PROFILE Petrosian radius intersects frame edge
0000000000020000 = INTERP Pixel(s) determined by interpolation.
0000000000040000 = SATURATED Saturated pixel(s)
0000000000080000 = NOTCHECKED Not checked for local peaks
0000000000100000 = SUBTRACTED BRIGHT object, wings subtracted
0000000000200000 = NOSTOKES No measured Stokes params
0000000000400000 = BADSKY Sky level so bad that highest pixel <0.
0000000000800000 = PETROFAINT Petrosian radius(es) rejected for low SB
0000000001000000 = TOO_LARGE Object too large to measure its profile
0000000002000000 = DEBLENDEDASPSF Deblender treated obj as PSF
0000000004000000 = DEBLEND_PRUNED At least one child was removed
0000000008000000 = ELLIPFAINT Object center fainter than the isophote
0000000010000000 = BINNED1 Object detected in 1x1 binned image
0000000020000000 = BINNED2 Object detected in 2x2 binned image
0000000040000000 = BINNED4 Object detected in 4x4 binned image
0000000080000000 = MOVED Possibly moving object
0000000100000000 = DEBLENDEDASMOVING A MOVED object treated as moving.
0000000200000000 = NODEBLEND_MOVING A MOVED object not treated as moving.
0000000400000000 = TOOFEWDETECTIONS Too few detections to deblend as moving.
0000000800000000 = BADMOVINGFIT Moving fit too poor to be believable.
0000001000000000 = STATIONARY Object consistent with being stationary.
0000002000000000 = PEAKSTOOCLOSE Some peaks merged into a single peak.
0000004000000000 = MEDIAN_CENTER Center given is of median-smoothed image.
0000008000000000 = LOCAL_EDGE Center too close to an edge.
0000010000000000 = BADCOUNTSERROR Too few good pixels, error underestimated
0000020000000000 = BADMOVINGFIT_CHILD Moving child's velocity fit too poor
0000040000000000 = DEBLENDUNASSIGNEDFLUX After deblending flux not assigned
0000080000000000 = SATUR_CENTER Center is close to saturated pixel(s)
0000100000000000 = INTERP_CENTER Center is close to interpolated pixel(s)
0000200000000000 = DEBLENDEDATEDGE Object close to edge was deblended
0000400000000000 = DEBLEND_NOPEAK No detected peak within this child
0000800000000000 = PSFFLUXINTERP PSF flux from interpolated pixels > 20%
0001000000000000 = TOOFEWGOOD_DETECTIONS Too few good detections
0002000000000000 = CENTEROFFAIMAGE At least one peak's center lay off image
0004000000000000 = DEBLEND_DEGENERATE Identical candidate children, 1 retained
0008000000000000 = BRIGHTESTGALAXYCHILD Brightest member classified as galaxy
0010000000000000 = CANONICAL_BAND Band chosen as 'Canonical', generally r
0020000000000000 = AMOMENT_FAINT Object too faint to measure moments
0040000000000000 = AMOMENT_SHIFT Centroid shift too large
0080000000000000 = AMOMENT_MAXITER Maximum number of iterations exceeded
0100000000000000 = MAYBE_CR Object could actually be a cosmic ray
0200000000000000 = MAYBE_EGHOST Object could actually be a ghost
0400000000000000 = NOTCHECKED_CENTER Object center in a region not searched
0800000000000000 = OBJECT2HASSATUR_DN Trails included in estimated flux.
1000000000000020 = OBJECT2DEBLENDPEEPHOLE Deblend modified by peephole
2000000000000020 = GROWN_MERGED Growing led to a merger
4000000000000020 = HAS_CENTER Object has a canonical center
8000000000000020 = RESERVED Not used
------------------------------------------------------------------------------
Note (4): PSF and Petrosian magnitudes have been set to NULL values when
corresponding errors>100 and errors >100 have been set to NULL values
by CDS.
Note (5): Status flags written in decimal, full description available at
http://skyserver.sdss.org/dr16/en/help/browser/browser.aspx#
&&history=enum+ResolveStatus+E
------------------------------------------------------------------------------
00000001 = RUN_PRIMARY Object status set in reference to its own run
00000002 = RUN_RAMP Object in what would be the overlap area of a field
00000004 = RUN_OVERLAPONLY Object only appears in the overlap between 2 fields
00000008 = RUN_IGNORE Bright or parent object that should be ignored
00000010 = RUN_EDGE Object near lowest or highest column
00000020 = RUN_DUPLICATE Duplicate measurements of same pixels in 2 fields
00000100 = SURVEY_PRIMARY Primary observation within survey (mode=1)
00000200 = SURVEY_BEST Best observation in full survey, but not primary.
00000400 = SURVEY_SECONDARY Repeat (independent) observation (mode=2)
00000800 = SURVEY_BADFIELD In field with score=0
00001000 = SURVEY_EDGE Not kept as secondary
------------------------------------------------------------------------------
Further explanations to use this flag:
http://www.sdss.org/dr17/algorithms/resolve/
Note (6): Columns from the "SpecObjAll" table:
http://skyserver.sdss.org/dr16/en/help/browser/browser.aspx#
&&history=description+SpecObjAll+U
Note (7): The response curves of the SDSS filters (u g r i z) can be found on
the SDSS pages: http://classic.sdss.org/dr7/instruments/imager
The central wavelength and FWHM are:
-----------------------------------------------
(nm) u' g' r' i' z'
-----------------------------------------------
lambda 354.3 477.0 623.1 762.5 913.4
FWHM 56.7 138.7 137.3 152.6 95.0
-----------------------------------------------
Note that the ugriz magnitudes are not exactly on the AB scale
for the u-band (uAB=umag-0.04) and z-band (zAB=zmag+0.02)
(http://www.sdss.org/dr16/algorithms/fluxcal/#SDSStoAB)
Note (8): the spectroscopic source types are described here:
http://skyserver.sdss.org/dr16/en/help/browser/browser.aspx#
&&history=enum+SourceType+E
Note (9): the "zwarning" flag is a number made of the following bits:
1 = sky fiber
2 = too little wavelength coverage
4 = chi-squared of best fit is too close to that of second best
8 = synthetic spectrum is negative
16 = fraction of points more than 5 sigma away from best model
is too large (>5%)
32 = chi-squared minimum at edge of the redshift fitting range
64 = a QSO line exhibits negative emission (triggered only in QSO
spectra if CIV, CIII, MgII, Hbeta, or Halpha has lineArea+3*(lineArea)<0)
128 = the fiber was unplugged, so no spectrum obtained
See http://skyserver.sdss.org/dr16/en/help/browser/browser.aspx#
&&history=search+SpeczWarning
Note (10): the spectroscopic subclass includes:
* for GALAXY classes: BROADLINE, STARFORMING, STARBURST, AGN
* for STAR classes: MK spectral sub-classes, CV=Catataclysmic Variable,
Carbon stars (Carbon, Carbon_lines), white dwarfs (WD, WDcooler,
WDhotter, WDmagnetic, CarbonWD, CalciumWD)
Note (11): Columns from the "ProperMotions" table:
http://skyserver.sdss.org/dr16/en/help/browser/browser.aspx#
&&history=description+ProperMotions+U
Note (12): Columns from the "Photoz" table:
http://skyserver.sdss.org/dr16/en/help/browser/browser.aspx#
&&history=description+Photoz+U
Note (13): Columns from the "Field" table:
http://skyserver.sdss.org/dr16/en/help/browser/browser.aspx#
&&history=description+Field+U
--------------------------------------------------------------------------------
Acknowledgements:
It is a pleasure to thank Aniruddha R. Thakar [thakar at jhu . edu] and
Victor Paul [victor.paul at jhu . edu], who helped us to build this
catalogue.
History:
Data retrieved from http://skyserver.sdss.org/dr16
(End) G. Monari, F.-X. Pineau, E. Perret [CDS] 25-Jan-2022