J/MNRAS/510/2261 H-ATLAS DR3 NIR counterparts in SGP field (Ward+, 2022)
Herschel-ATLAS Data Release. III Near-infrared counterparts in the South
Galactic Pole field - another 100000 submillimetre galaxies.
Ward B.A., Eales S.A., Pons E., Smith M.W.L., Mcmahon R.G., Dunne L.,
Ivison R.J., Maddox S.J., Negrello M.
<Mon. Not. R. Astron. Soc. 510, 2261-2276 (2022)>
=2022MNRAS.510.2261W 2022MNRAS.510.2261W (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Galaxies, IR ; Stars, normal ; Infrared sources ;
Space observations ; Optical ; Millimetric/submm sources ;
Cross identifications ; Combined data ; Positional data ;
Photometry ; Models ; Photometry, classification ; Redshifts ;
Spectroscopy ; Active gal. nuclei ; QSOs ; Gravitational lensing
Keywords: methods: statistical - catalogues - submillimetre: galaxies
Abstract:
In this paper, we present the third data release (DR3) of the Herschel
Astrophysical Terahertz Large Area Survey (H-ATLAS). We identify
likely near- infrared counterparts to submillimetre sources in the
South Galactic Pole (SGP) field using the VISTA VIKING survey. We
search for the most probable counterparts within 15 arcsec of each
Herschel source using a probability measure based on the ratio between
the likelihood the true counterpart is found close to the
submillimetre source and the likelihood that an unrelated object is
found in the same location. For 110374 (57.0 per cent) sources, we
find galaxies on the near-infrared images where the probability that
the galaxy is associated to the source is greater than 0.8. We
estimate the false identification rate to be 4.8 per cent, with a
probability that the source has an associated counterpart on the
VIKING images of 0.835 ± 0.009. We investigate the effects of
gravitational lensing and present 41 (0.14 deg-2) candidate lensed
systems with observed flux densities >100 mJy at 500 µm. We include
in the data release a probability that each source is gravitationally
lensed and discover an additional 5923 sources below 100 mJy that have
a probability greater than 0.94 of being gravitationally lensed. We
estimate that ∼400-1000 sources have multiple true identifications in
VIKING based on the similarity of redshift estimates for multiple
counterparts close to a Herschel source. The data described in this
paper can be found at the H-ATLAS website.
Description:
This paper describes the results of a search for the counterparts in
the SGP, the largest of the H-ATLAS fields, which has coverage from
both the VISTA Kilo-degree Infrared Galaxy (VIKING) survey and the
Kilo Degree Survey (KiDS; de Jong et al. 2013Msngr.154...44D 2013Msngr.154...44D) in
near-infrared (ZYJHKs) and optical (ugri) wavebands, respectively, as
well as spectroscopic redshifts from the 2dF survey. A preliminary
counterpart identification analysis using the Two Micron All Sky
Survey (2MASS; Skrutskie et al. 2006AJ....131.1163S 2006AJ....131.1163S, Cat. VII/233)
found just 3444 Herschel sources in the SGP within 5 arcsec of a 2MASS
galaxy. Here, we present a comprehensive identification analysis using
the likelihood ratio (LR) technique for identifying VIKING
counterparts to H-ATLAS DR2 sources, (i.e paragraph taken from the
section Introductions).
We use the H-ATLAS DR2 catalogue described in Maddox et al.
(2018ApJS..236...30M 2018ApJS..236...30M, Cat. J/ApJS/236/30), which contains 153367
sources for the NGP field and 193527 sources for the SGP detected at
more than 4 σ significance in any of the 250-, 350- or 500-µm
SPIRE bands. Sources were detected from the SPIRE maps using the MADX
(Maddox & Dunne 2020MNRAS.493.2363M 2020MNRAS.493.2363M) algorithm that identifies sources
from peaks in the signal-to-noise ratio (SNR) maps, (i.e see section
2.1 Herschel-ATLAS sources). For VIKING catalogue, The Visible and
Infrared Survey Telescope for Astronomy (VISTA) is a 4-m wide field
survey telescope located at the European Southern Observatory's (ESO)
Paranal observatory. One of the public surveys of VISTA is VIKING,
imaging a total of 1500 deg2 across the celestial equator and
southern Galactic cap in five filters: Z, Y, J, H, and Ks, covering
this area to a 5 σ depth at these bands, respectively (Edge et
al. 2013Msngr.154...32E 2013Msngr.154...32E, Cat. II/329 and Cat. II/343, and also SDSS
optical coverage). The area of the VIKING survey covering the southern
Galactic cap spans a width of 10 degrees. The H-ATLAS fields were
chosen to maximize the coverage with complementary multiwavelength
data, including an overlap with the VIKING survey of more than 360
square degrees (i.e refer to section 2.2 VISTA VIKING counterparts).
Then, taking out the best of Star-galaxy classifier method (i.e
section 2.3) and counterparts idetntifications analysis (i.e section 3
Likelihood ratio method), we construct two tables, hatlaspg.dat
comprises only most reliable near-infrared VIKING counterparts to the
H-ATLAS 250-µm sources from the SGP field and hsgall.dat contains
all found VIKING counterparts IDs even if they correspond to star
contaminations. As resumed in the section 4 Results (specifically for
hatlaspg.dat), the LR and reliability of all possible matches within
15 arcsec of each SPIRE source were calculated using equations (2) and
(4). The SPIRE catalogue contains 193527 sources of which 190788 have
at least one possible counterpart within the search radius. Within
this sample, 180030 are sources with SNR250 => 4, 181373 (95.1 per
cent) are classified as extragalactic objects, and 9415 (4.9 per cent)
as stars.
Next (also fully detailed in section 4), photometric redshifts are
estimated for the near-infrared counterparts by matching our catalogue
to the SGP data found in HELP catalogue (Vaccari 2016ASSP...42.....N 2016ASSP...42.....N)
and with spectroscopic redshifts training set from the 2dF, 6dF, 2MRS,
and SRSS2 surveys which covers GAMA fields (methods described in
sections 4.2.2 HELP redshifts and 4.3 Source counts). These results
are also presented in our two tables. Finally, refering the section 5
Lensed population, we provide a pLens probability to be lensed in
hatlaspg.dat.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
hatlasgp.dat 965 193527 H-ATLAS DR3 catalogue for the SGP field keeping
the best VIKING ID counterparts
hsgpall.dat 968 1008098 H-ATLAS DR3 catalogue for the SGP field with
all included VIKING couterparts IDs
--------------------------------------------------------------------------------
See also:
J/ApJS/236/30 : Herschel-ATLAS (H-ATLAS) DR2 (Maddox+, 2018)
II/329 : VIKING catalogue data release 1 (Edge+, 2013)
II/343 : VIKING catalogue data release 2 (Edge+, 2016)
II/294 : The SDSS Photometric Catalog, Release 7
(Adelman-McCarthy+, 2009)
II/347 : KiDS-ESO-DR3 multi-band source catalog (de Jong+, 2017)
VII/233 : 2MASS All-Sky Extended Source Catalog (XSC)
(IPAC UMass, 2003-2006)
J/ApJS/199/26 : The 2MASS Redshift Survey (2MRS) (Huchra+, 2012)
J/AJ/116/1 : Southern Sky Redshift Survey (Da Costa+, 1998)
VII/250 : The 2dF Galaxy Redshift Survey (2dFGRS)
(2dFGRS Team, 1998-2003)
VII/259 : 6dF galaxy survey final redshift release (Jones+, 2009)
www.h-atlas.org : H-ATLAS data web page
Byte-by-byte Description of file: hatlasgp.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 22 A22 --- HATLAS HATLAS IAU name designation
(HATLASJHHMMSS.s+DDMMSS) (HATLASIAUID)
24- 37 A14 --- ID HATLAS short name as SGP.DR2.XXXXXX (IDNAME)
39- 48 F10.6 deg RAdeg Right ascension of HATLAS source (J2000) (RA)
50- 59 F10.6 deg DEdeg Declination of HATLAS source (J2000) (DEC)
61- 68 F8.6 Jy F250 SPIRE flux 250um band from MF (F250)
70- 79 F10.7 Jy F350 SPIRE flux 350um band from MF (F350)
81- 90 F10.7 Jy F500 SPIRE flux 500um band from MF (F500)
92-104 F13.11 Jy e_F250 Mean error 1σ of F250 assuming
confusion noise variable with flux (E250)
106-118 F13.11 Jy e_F350 Mean error 1σ of F350 assuming
confusion noise variable with flux (E350)
120-132 F13.11 Jy e_F500 Mean error 1σ of F500 assuming
confusion noise variable with flux (E500)
134-144 F11.8 Jy F250b SPIRE best flux 250um band from
aperture photometry (F250BEST)
146-158 F13.11 Jy e_F250b Mean error 1σ of F250b (E250BEST)
160-167 F8.4 arcsec a_F250b ? Aperture photometry radius used to measure
F250b (AP250)
169-180 F12.9 Jy F350b SPIRE best flux 350um band from aperture
photometry (F350BEST)
182-194 F13.11 Jy e_F350b Mean error 1σ of F350b (E350BEST)
196-203 F8.4 arcsec a_F350b ? Aperture photometry radius used to measure
F350b (AP350)
205-216 F12.9 Jy F500b SPIRE best flux 500um band from aperture
photometry (F500BEST)
218-230 F13.11 Jy e_F500b Mean error 1σ of F500b (E500BEST)
232-239 F8.4 arcsec a_F500b ? Aperture photometry radius used to measure
F500b (AP500)
241-258 F18.15 Jy F100b ?=-1 SPIRE best flux 100um band from aperture
photometry (F100BEST)
260-271 F12.9 Jy e_F100b ?=-1 Mean error 1σ of F100b (E100BEST)
273-280 F8.4 arcsec a_F100b ? Aperture photometry radius used to measure
F100b (AP100)
282-299 F18.15 Jy F160b ?=-1 SPIRE best flux 160um band from aperture
photometry (F160BEST)
301-312 F12.9 Jy e_F160b ?=-1 Mean error 1σ of F160b (E160BEST)
314-321 F8.4 arcsec a_F160b ? Aperture photometry radius used to measure
F160b (AP160)
323-327 F5.1 arcsec MinAxis ? Minor semi-axis of customised aperture
(AP_RMIN)
329-338 F10.6 deg PA ? Positional angle of customised
aperture (AP_PA)
340-357 F18.14 deg NIRRAdeg ? Position of the near-IR ID from VIKING
(NEARIR_RA)
359-375 F17.13 deg NIRDEdeg ? Position of the near-IR ID from VIKING
(NEARIR_DEC)
377-394 F18.15 arcsec Sep ? Angular separation between HATLAS position
and near-IR position (SEPARATION)
396-414 F19.14 --- L ? Likelihood the VIKING object is related to
the HATLAS source (LIKELIHOOD) (G1)
416-432 F17.15 --- R ? Reliability of the VIKING object being
related to the HATLAS source (RELIABILITY)
(G2)
434-454 E21.15 --- pStar ? VIKING probability that the source
is a star (pStar) (G3)
456 I1 --- GS ? Galaxy/star key code (GS_KEY) (G4)
458 I1 --- f_GS [0/1]? Galaxy/star flag (0=star 9411 objects/
1=gal 179971 objects ∼93 per cent of the
sample) (GS_FLAG) (G5)
460-480 E21.15 --- zSPIRE Photometric redshift estimated from SPIRE
fluxes (Z_SPIRE)
482-502 E21.15 --- e_zSPIRE Error in photometric redshift estimated from
SPIRE fluxes (Z_SPIREERR)
504-515 I12 --- VIKING ? VIKING ID if present (VIKING_OBJID)
517-530 E14.7 mag Zmag ? Apparent aperture corrected mangitude in
VIKING NIR Z band with 2 arcsec aperture
diameter (ZAPERMAG3)
532-549 E18.11 mag e_Zmag ? Mean error of Zmag (ZAPERMAG3ERR)
551-564 E14.7 mag Ymag ? Apparent aperture corrected magnitude in
VIKING NIR Y band with 2 arcsec aperture
diameter (YAPERMAG3)
566-582 E17.10 mag e_Ymag ? Mean error of Ymag (YAPERMAG3ERR)
584-597 E14.7 mag Jmag ? Apparent aperture corrected magnitude in
VIKING NIR J band with 2 arcsec aperture
diameter (JAPERMAG3)
599-615 E17.10 mag e_Jmag ? Mean error of Jmag (JAPERMAG3ERR)
617-630 E14.7 mag Hmag ? Apparent aperture corrected magnitude in
VIKING NIR H band with 2 arcsec aperture
diameter (HAPERMAG3)
632-648 E17.10 mag e_Hmag ? Mean error of Hmag (HAPERMAG3ERR)
650-663 E14.7 mag Ksmag ? Apparent aperture corrected magnitude in
VIKING NIR Ks band with 2 arcsec aperture
diameter (KSAPERMAG3)
665-681 E17.10 mag e_Ksmag ? Mean error of Ksmag (KSAPERMAG3ERR)
683-698 A16 --- 2MASS 2MASS Extended Source Catalog ID if present
(2MASSEXT_ID)
700-709 F10.6 deg 2MRAdeg ? Right ascension from ID of 2MASS Extended
Source Catalog (J2000) (2MASS_RA)
711-718 F8.4 deg 2MDEdeg ? Declination from ID of 2MASS Extended
Source Catalog (2MASS_DEC)
720-726 F7.4 mag KronJmag ? Apparent Kron magnitude in J band
extracted with the K fiducial Kron
elliptical aperture semi-major axis (JMAG)
728-733 F6.4 mag e_KronJmag ? Mean error of KronJmag (JMAGERR)
735-741 F7.4 mag KronHmag ? Apparent Kron magnitude in H band
extracted with the K fiducial Kron
elliptical aperture semi-major axis (HMAG)
743-748 F6.4 mag e_KronHmag ? Mean error of KronHmag (HMAGERR)
750-755 F6.3 mag KronKmag ? Apparent Kron magnitude in K band
extracted with the K fiducial Kron
elliptical aperture semi-major axis (KMAG)
757-761 F5.3 mag e_KronKmag ? Mean error of KronKmag (KMAGERR)
763-791 A29 --- KiDSDR4 KiDS ID if present in format
(KiDSDR4 JHHMMSS.sss-DDMMSSSS.ss)
(KiDSIAUID)
793-801 F9.6 mag gmag ? Apparent SDSS KiDs g magnitude within
optimal minimum aperture (MAGGAAPg)
803-814 E12.6 mag e_gmag ? Mean error of gmag (MAGERRGAAPg)
816-824 F9.6 mag imag ? Apparent SDSS KiDs i magnitude within
optimal minimum aperture (MAGGAAPi)
826-837 E12.6 mag e_imag ? Mean error of imag (MAGERRGAAPi)
839-865 A27 --- HELPID HELP ID if present in format
(HELP_JHHMMSS.sss-DDMMSSSS.sss)
(HELPIAUID)
867-872 F6.4 --- zHELP ? Median of the primary redshift peak above
80% HPD credible interval as explained in
the section 4.2 Photometric redshifts (Z_PHOT)
874-890 F17.15 --- e_zHELP ? Mean error of zHELP assuming a Gaussian
HPD credible interval as explained in the
section 4.2.2 HELP redshifts (Z_PHOTERR)
892-897 F6.4 --- zHELPmin ? Minimum redshift of the primary redshift
peak above 80% HPD credible interval as
explained in the section 4.2.2 HELP
redshifts (Z_PHOTMIN)
899-904 F6.4 --- zHELPmax ? Maximum redshift of the primary redshift
peak above 80% HPD credible interval as
explained in the section 4.2.2 HELP
redshifts (Z_PHOTMAX)
906-922 F17.15 --- pLens ? Probability (>94%) that HATLAS source
is lensed by near-IR ID (column only for
single IDs) as detailed in the section 5
Lensed population (LENSEDPROB)
924-930 F7.5 --- zSPEC ? Spectroscopic redshift measurement
(Z_SPEC) (G5)
932-933 I2 --- r_zSPEC ? Survey that produced the spectroscopic
redshift (Z_SOURCE) (G5)
935 I1 --- q_zSPEC ? Quality flag of the spectroscopic redshift
(Z_QUAL) (G6)
937-941 F5.3 --- RzSPEC [0.305/0.998]? Reliability of spectroscopic
redshift (REL) (G6)
943-963 A21 --- ObjID Object ID for the source of the spectroscopic
measurement (OBJID)
965 I1 --- f_ObjID [0/1]? Flag if the survey provides information
identifying the object as a QSO or AGN
(1=QSO/AGN, 0=otherwise) (AGN)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: hsgpall.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 22 A22 --- HATLAS HATLAS IAU name designation
(HATLASJHHMMSS.s+DDMMSS) (HATLASIAUID)
24- 37 A14 --- ID HATLAS short name as SGP.DR2.XXXXXX (IDNAME)
39- 48 F10.6 deg RAdeg Right ascension of HATLAS source (J2000) (RA)
50- 59 F10.6 deg DEdeg Declination of HATLAS source (J2000) (DEC)
61- 68 F8.6 Jy F250 SPIRE flux 250um band from MF (F250)
70- 79 F10.7 Jy F350 SPIRE flux 350um band from MF (F350)
81- 90 F10.7 Jy F500 SPIRE flux 500um band from MF (F500)
92-104 F13.11 Jy e_F250 Mean error 1σ of F250 assuming
confusion noise variable with flux (E250)
106-118 F13.11 Jy e_F350 Mean error 1σ of F350 assuming
confusion noise variable with flux (E350)
120-132 F13.11 Jy e_F500 Mean error 1σ of F500 assuming
confusion noise variable with flux (E500)
134-151 F18.15 Jy F250b SPIRE best flux 250um band from
aperture photometry (F250BEST)
153-166 F14.12 Jy e_F250b Mean error 1σ of F250b (E250BEST)
168-176 F9.4 arcsec a_F250b ?=-99 Aperture photometry radius used to
measure F250b (AP250)
178-189 F12.9 Jy F350b SPIRE best flux 350um band from aperture
photometry (F350BEST)
191-203 F13.11 Jy e_F350b Mean error 1σ of F350b (E350BEST)
205-213 F9.4 arcsec a_F350b ?=-99 Aperture photometry radius used
to measure F350b (AP350)
215-225 F11.8 Jy F500b SPIRE best flux 500um band from aperture
photometry (F500BEST)
227-240 F14.12 Jy e_F500b Mean error 1σ of F500b (E500BEST)
242-250 F9.4 arcsec a_F500b ?=-99 Aperture photometry radius used
to measure F500b (AP500)
252-269 F18.15 Jy F100b ?=-1.000000000000000 SPIRE best flux 100um
band from aperture photometry (F100BEST)
271-281 F11.8 Jy e_F100b ?=-1.000000000 Mean error 1σ of
F100b (E100BEST)
283-291 F9.4 arcsec a_F100b ?=-99.0000 Aperture photometry radius used
to measure F100b (AP100)
293-310 F18.15 Jy F160b ?=-1 SPIRE best flux 160um band from aperture
photometry (F160BEST)
312-322 F11.8 Jy e_F160b ?=-1 Mean error 1σ of F160b (E160BEST)
324-332 F9.4 arcsec a_F160b ?=-99 Aperture photometry radius used to
measure F160b (AP160)
334-339 F6.1 arcsec MinAxis ? Minor semi-axis of customised aperture
(AP_RMIN)
341-351 F11.6 deg PA ?=-99 Positional angle of customised aperture
(AP_PA)
353-370 F18.14 deg NIRRAdeg ? Position of the near-IR ID from VIKING
(NEARIR_RA)
372-389 F18.14 deg NIRDEdeg ? Position of the near-IR ID from VIKING
(NEARIR_DEC)
391-407 F17.14 arcsec Sep ? Angular separation between HATLAS position
and near-IR position (SEPARATION)
409-428 F20.15 --- L ? Likelihood the VIKING object is related to
the HATLAS source (LIKELIHOOD) (G1)
430-446 F17.15 --- R ? Reliability of the VIKING object being
related to the HATLAS source (RELIABILITY)
(G2)
448-468 F21.15 --- pStar ? VIKING probability that the source
is a star (pStar) (G3)
470 A1 --- GS ? Galaxy/star key code (GS_KEY) (G4)
472 A1 --- f_GS [0/1]? Galaxy/star flag (0=star 9411 objects/
1=gal 179971 objects ∼93 per cent of the
sample) (GS_FLAG) (G5)
474-494 F21.15 --- zSPIRE Photometric redshift estimated from SPIRE
fluxes (Z_SPIRE)
496-516 F21.15 --- e_zSPIRE Error in photometric redshift estimated from
SPIRE fluxes (Z_SPIREERR)
518-529 I12 --- VIKING ? VIKING ID if present (VIKING_OBJID)
531-544 E14.7 mag Zmag ? Apparent aperture corrected mangitude in
VIKING NIR Z band with 2 arcsec aperture
diameter (ZAPERMAG3)
546-561 E16.9 mag e_Zmag ? Mean error of Zmag (ZAPERMAG3ERR)
563-576 E14.7 mag Ymag ? Apparent aperture corrected magnitude in
VIKING NIR Y band with 2 arcsec aperture
diameter (YAPERMAG3)
578-594 E17.10 mag e_Ymag ? Mean error of Ymag (YAPERMAG3ERR)
596-609 E14.7 mag Jmag ? Apparent aperture corrected magnitude in
VIKING NIR J band with 2 arcsec aperture
diameter (JAPERMAG3)
611-627 E17.10 mag e_Jmag ? Mean error of Jmag (JAPERMAG3ERR)
629-642 E14.7 mag Hmag ? Apparent aperture corrected magnitude in
VIKING NIR H band with 2 arcsec aperture
diameter (HAPERMAG3)
644-660 E17.10 mag e_Hmag ? Mean error of Hmag (HAPERMAG3ERR)
662-675 E14.7 mag Ksmag ? Apparent aperture corrected magnitude in
VIKING NIR Ks band with 2 arcsec aperture
diameter (KSAPERMAG3)
678-692 E15.6 mag e_Ksmag ? Mean error of Ksmag (KSAPERMAG3ERR)
694-709 A16 --- 2MASS 2MASS Extended Source Catalog ID if present
(2MASSEXT_ID)
712-721 F10.6 deg 2MRAdeg ? Right ascension from ID of 2MASS Extended
Source Catalog (J2000) (2MASS_RA)
723-730 F8.4 deg 2MDEdeg ? Declination from ID of 2MASS Extended
Source Catalog (2MASS_DEC)
732-738 F7.4 mag KronJmag ? Apparent Kron magnitude in J band
extracted with the K fiducial Kron
elliptical aperture semi-major axis (JMAG)
740-745 F6.4 mag e_KronJmag ? Mean error of KronJmag (JMAGERR)
747-753 F7.4 mag KronHmag ? Apparent Kron magnitude in H band
extracted with the K fiducial Kron
elliptical aperture semi-major axis (HMAG)
755-760 F6.4 mag e_KronHmag ? Mean error of KronHmag (HMAGERR)
762-767 F6.3 mag KronKmag ? Apparent Kron magnitude in K band
extracted with the K fiducial Kron
elliptical aperture semi-major axis (KMAG)
769-773 F5.3 mag e_KronKmag ? Mean error of KronKmag (KMAGERR)
775-803 A29 --- KiDSDR4 KiDS ID if present in format
(KiDSDR4 JHHMMSS.sss-DDMMSSSS.ss)
(KiDSIAUID)
805-813 F9.6 mag gmag ? Apparent SDSS KiDs g magnitude within
optimal minimum aperture (MAGGAAPg)
815-826 E12.6 mag e_gmag ? Mean error of gmag (MAGERRGAAPg)
828-836 F9.6 mag imag ? Apparent SDSS KiDs i magnitude within
optimal minimum aperture (MAGGAAPi)
838-849 E12.6 mag e_imag ? Mean error of imag (MAGERRGAAPi)
851-877 A27 --- HELPID HELP ID if present in format
(HELP_JHHMMSS.sss-DDMMSSSS.sss)
(HELPIAUID)
879-886 F8.4 --- zHELP ? Median of the primary redshift peak above
80% HPD credible interval as explained in
the section 4.2 Photometric redshifts (Z_PHOT)
888-904 F17.15 --- e_zHELP ? Mean error of zHELP assuming a Gaussian
HPD credible interval as explained in the
section 4.2.2 HELP redshifts (Z_PHOTERR)
906-913 F8.4 --- zHELPmin ? Minimum redshift of the primary redshift
peak above 80% HPD credible interval as
explained in the section 4.2.2 HELP
redshifts (Z_PHOTMIN)
915-922 F8.4 --- zHELPmax ? Maximum redshift of the primary redshift
peak above 80% HPD credible interval as
explained in the section 4.2.2 HELP
redshifts (Z_PHOTMAX)
924-933 F10.7 --- zSPEC ? Spectroscopic redshift measurement
(Z_SPEC) (G5)
935-936 I2 --- r_zSPEC ? Survey that produced the spectroscopic
redshift (Z_SOURCE) (G5)
938 I1 --- q_zSPEC ? Quality flag of the spectroscopic redshift
(Z_QUAL) (G6)
940-944 A5 --- RzSPEC ? Reliability of spectroscopic
redshift (REL) (G6)
946-966 A21 --- ObjID Object ID for the source of the spectroscopic
measurement (OBJID)
968 I1 --- f_ObjID [0/1]? Flag if the survey provides information
identifying the object as a QSO or AGN
(1=QSO/AGN, 0=otherwise) (AGN)
--------------------------------------------------------------------------------
Global notes:
Note (G1): The LR method is used to identify the most reliable near-infrared
counterparts to the 250-µm sources from the SGP field. This
method, developed by Sutherland & Saunders (1992MNRAS.259..413S 1992MNRAS.259..413S),
assigns to all counterparts a probability of being the true
identification defined by the ratio of two likelihoods, the
likelihood of the true counterpart being observed at a magnitude m
and separation r from the source, and the likelihood of a background
object being found with the same properties. The LR for each possible
counterpart is defined as L in the equation 2 of the section 3
Likelihood ratio method.
Note (G2): Hereafter, the probability that an object at a distance r from the
source with magnitude m is the true ID is then given by the
reliability R = L/(L+1) of the section 3 Likelihood ratio
method as shown on Sutherland & Saunders (1992MNRAS.259..413S 1992MNRAS.259..413S), (also
see the Rj equation 4 for a source with multiple possible
counterparts case).
Note (G3): As explained in the dedicated section 2.3 Star-galaxy classifier, we
classify as stellar any object with pStar, a probability that the
object is a star based on a VIKING shape parameter, greater than
0.95.
Note (G4): The VIKING positions are matched to the closest KiDS object to within
0.5 arcsec to obtain g and i band magnitudes. These are used to
separate stars from extragalactic sources using a cut on the g-i/J-Ks
colour-colour diagram (i.e see the section 2.3 Star-galaxy classifier
figure 1), The GS defines how each near-infrared object is classified
and by which condition as follows:
0 = Stellar with pStar > 0.95
1 = Galaxy in J-Ks/g-i colour plane grey points in fig 1
2 = Stellar in J-Ks/g-i colour plane red points in fig 1
3 = Galaxy with J-Ks > 0.98
4 = Stellar with J-Ks < 0.42
5 = Stellar with pStar > 0.70
6 = Galaxy all remaining objects
Note (G5): Spectroscopic and photometric redshifts are obtained from Herschel
Extragalactic Legacy Project (HELP). We consider the closest match
within 0.5 arcsec to the near-infrared positions as being the correct
photometric/spectroscopic counterpart. The catalogue of spectroscopic
redshifts is formed from the merged catalogues of the 2dF, 6dF, 2MRS
Huchra et al. (2012ApJS..199...26H 2012ApJS..199...26H, Cat. J/ApJS/199/26) and SRSS2
Da Costa et al. (1998AJ....116....1D 1998AJ....116....1D, Cat. J/AJ/116/1) surveys.
The source of each redshift in the catalogue is given by Z_SOURCE.
Codes are as follows:
1 = 2dF Colless et al. 2001MNRAS.328.1039C 2001MNRAS.328.1039C, Cat. VII/250
2 = 6dF Jones et al. 2009MNRAS.399..683J 2009MNRAS.399..683J, Cat. VII/259
4 = 2MRS Huchra et al. 2012ApJS..199...26H 2012ApJS..199...26H, Cat. J/ApJS/199/26
8 = SRSS2 Da Costa et al. 1998AJ....116....1D 1998AJ....116....1D, Cat. J/AJ/116/1
Other numbers indicate that the source has a redshift in more than
one redshift catalogue. For example, ZSOURCE = 5 indicates that
there are redshifts in the both the 2dF and 2MRS survey (5=4+1), more
details in the h-atlas readme
(https://www.h-atlas.org/public_data/DR3/README).
Note (G6): The Z_QUAL flag gives an indication of the quality of the estimated
redshift using the method of Colless et al. (2001MNRAS.328.1039C 2001MNRAS.328.1039C,
Cat. VII/250). Spectroscopic redshifts have quality flags as follows:
1 = No redshift could be estimated
2 = A possible but doubtful redshift estimate
3 = Means a probable redshift (notionally 90% confident)
4 = Means a reliable redshift (notionally 99% confident)
5 = Means a reliable redshift and high quality spectrum
We recommend using spectroscopic redshifts with Z_QUAL => 3 for
science purposes. For the surveys where the exact reliability
measurements are available, their reliability value is given under
REL, which can take a value in the range 0 - 1, more details in
the h-atlas readme (https://www.h-atlas.org/public_data/DR3/README).
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History:
From electronic version of the journal
(End) Luc Trabelsi [CDS] 06-Nov-2024