J/MNRAS/521/3384ivo://CDS.VizieR/J/MNRAS/521/3384CDSEltvedt A.M.Shanks T.Metcalfe N.Ansarinejad B.Barrientos L.F.,Sharp R.Malik U.Murphy D.N.A.Irwin M.Wilson M.Alexander D.M.,Kovacs A.Garcia-Bellido J.Ahlen S.Brooks D.De La Macorra A.,Font-Ribera A.Gontcho A Gontcho S.Honscheid K.Meisner A.Miquel R.,Nie J.Tarle G.Vargas-Magana M.Zhou Z.2026-07-27T09:39:47Z2026-06-18T16:17:38ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frquasarsphotometryvisible-astronomyinfrared-astronomyredshiftedastronomical-object-identificationWe present the VST ATLAS Quasar Survey, consisting of ~1229000 quasar (QSO) candidates with 16 < g < 22.5 over ~4700 deg^2^. The catalogue is based on VST ATLAS+NEOWISE imaging surveys and aims to reach a QSO sky density of 130 deg^-2^ for z < 2.2 and ~30 deg-2 for z > 2.2. To guide our selection, we use X-ray/UV/optical/MIR data in the extended William Herschel Deep Field (WHDF) where we find a g < 22.5 broad-line QSO density of 269 +/- 67 deg^-2^, roughly consistent with the expected ~196 deg^-2^. We find that ~25 per cent of our QSOs are morphologically classed as optically extended. Overall, we find that in these deep data, MIR, UV, and X-ray selections are ~70-90 per cent complete while X-ray suffers less contamination than MIR and UV. MIR is however more sensitive than X-ray or UV to z > 2.2 QSOs at g < 22.5 and the S_X_(0.5-10keV) > 1*10^-14^ erg/cm^-2^/s^-1^ limit of eROSITA. We adjust the selection criteria from our previous 2QDES pilot survey and prioritize VST ATLAS candidates that show both UV and MIR excess, also selecting candidates initially classified as extended. We test our selections using data from DESI (which will be released in DR1) and 2dF to estimate the efficiency and completeness, and we use ANNz2 to determine photometric redshifts. Applying over the ~4700 deg^2^ ATLAS area gives us ~917000 z<2.2 QSO candidates of which 472 000 are likely to be z < 2.2 QSOs, implying a sky density of ~100 deg^-2^, which our WHDF analysis suggests will rise to at least 130 deg^-2^ when eROSITA X-ray candidates are included. At z > 2.2, we find ~310000 candidates, of which 169000 are likely to be QSOs for a sky density of ~36 deg^-2^.2023MNRAS.521.3384Ehttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/521/3384CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/520/1371 : VST ATLAS galaxy cluster I detections (Ansarinejad+, 2023)J/MNRAS/392/19 : The 2dF-SDSS QSO survey (Croom+, 2009)J/ApJS/225/1 : SpIES: the Spitzer IRAC Equatorial Survey (Timlin+, 2016)J/ApJS/199/3 : The quasars MMT-BOSS pilot survey (Ross+, 2012)J/ApJS/155/257 : NBC Quasar Candidate Catalog (Richards+, 2004)J/AJ/154/269 : A new photo-z method for quasars in Stripe 82 (Yang+, 2017)VII/250 : The 2dF Galaxy Redshift Survey (2dFGRS) (2dFGRS, 2003)VII/223 : The 2dF QSO Redshift Survey. V. The 10k catalogueII/363 : The band-merged unWISE Catalog (Schlafly+, 2019)II/350 : VLT Survey Telescope ATLAS (Shanks+, 2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/521/3384https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/521/3384http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/521/3384https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/521/3384https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/521/3384http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/521/3384GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/521/3384/janngc (Photometry of selected VST ATLAS QSO in NGC Northern Galactic Cap released in 31/01/2023)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/521/3384/janngc?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/521/3384/janngc?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/521/3384/janngc?GETtext/xml+votable180.050000true200.5310311445432-18.47926676410580.005555555555555556Cone search capability for table J/MNRAS/521/3384/jansgc (Photometry of selected VST ATLAS QSO in SGC Northern Galactic Cap released in 31/01/2023)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/521/3384/jansgc?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/521/3384/jansgc?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/521/3384/jansgc?GETtext/xml+votable180.050000true32.7220060719189-21.13042714469310.005555555555555556Cone search capability for table J/MNRAS/521/3384/marngc (Photometry of selected VST ATLAS QSO in NGC Northern Galactic Cap released in 06/03/2023)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/521/3384/marngc?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/521/3384/marngc?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/521/3384/marngc?GETtext/xml+votable180.050000true200.5310311445432-18.47926676410580.005555555555555556Cone search capability for table J/MNRAS/521/3384/marsgc (Photometry of selected VST ATLAS QSO in SGC Northern Galactic Cap released in 06/03/2023)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/521/3384/marsgc?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/521/3384/marsgc?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/521/3384/marsgc?GETtext/xml+votable180.050000true32.7220060719189-21.13042714469310.0055555555555555562/65-66 97-98 142 174 3/257-259 268 272 288 385 387 396-398 400-402 416-417 557-559 561-563 566-567 572 685-687 700 702 733-735 757 4/1025-1027 1076 1080 1092 1096 1156 1160 1539 1545 1547 1596-1598 1612-1614 1616-1618 1632-1634 1672-1673 1675-1678 1680-1682 2157-2159 2205-2207 2221-2223 2225-2227 2241-2243 2256 2258-2259 2292 2296 2429 2431 2517 2519 2735 2739 2763 2766-2767 2778-2779 2804 2806-2807 2812-2814 2909-2911 2925 2927 2929-2931 3024-3025 3027 3036-3037 3039 5/4097-4099 4308-4310 4312-4314 4324-4326 4328-4330 4372-4374 4376-4378 4388-4390 4392-4394 4628-4630 4632-4634 4644-4646 4648-4650 5666 5672-5674 6151 6179 6185-6187 6396-6398 6460-6462 6476-6478 6480-6482 6496-6498 6540-6542 6544-6546 6560-6562 6697 6716-6718 6732-6734 6736-6738 6752-6754 6789 6800-6802 7818 7840-7842 8606 8621-8623 8625-8627 8674 8680 8682-8683 8686 8797-8799 8813-8815 8817-8819 8861-8863 8877-8879 8881-8883 8897-8899 8961-8963 9028 9030-9031 9048 9050-9051 9054 9172-9174 9176-9178 9188-9190 9192-9194 9687 9693 9695 9723 10065-10067 10073 10101 10875 10935 10939 10951 10955 11050-11051 11062-11063 11106-11107 11110 11130 11222 11260-11262 11613-11615 11629-11631 11633-11635 11677-11679 11697-11699 11704-11705 11707 11713-11715 12052-12053 12055 12104-12105 12107 12132-12133 12135 12152-12153 12155 12244-12245 6/16385-16387 17244 17260 17264 17308 17324 17328 17344 17500 17516 17520 17564 17580 17584 17600 17664 17920 18524 18540 18544 18588 18604 18608 18624 18688 18944 22658 22700 23040 24599 24603 24615 24621 24623 24709 24711 24715 24737-24739 25596 25852 25916 25932 25936 25952 25996 26000 26016 26172 26188 26192 26208 26252 26256 26272 26785 26797 26876 26940 26956 26960 26976 27020 27024 27040 27153 27165 27212 27216 31264 31266-31267 31276 31278 31372 31392 34413-34415 34430 34461-34463 34477-34479 34481-34483 34497-34499 34690 34724 34726-34727 34738 34750 35165-35167 35181-35183 35185-35187 35229-35231 35245-35247 35249-35251 35265-35267 35421-35423 35437-35439 35441-35443 35485-35487 35501-35503 35505-35507 35521-35523 35585-35587 35841-35843 36116 36118-36119 36162 36168 36170-36171 36174 36196 36198-36199 36210 36700 36716 36720 36764 36780 36784 36800 38741 38743 38771 38777-38779 38863 38885 38887 38891 40221 40257-40259 40289 40301 40401 40413 43499 43514-43515 43517-43519 43735 43739 43751 43755 43799 43803 43815 43819 44191 44194 44197-44199 44234-44235 44237-44239 44247 44418-44419 44421-44423 44434-44435 44444 44446-44447 44512 44514-44515 44524 44526 44880 44882-44883 44894-44895 45052 46429-46431 46445-46447 46449-46451 46493-46495 46509-46511 46513-46515 46529-46531 46685-46687 46701-46703 46705-46707 46749-46751 46772-46773 46775 46785-46787 46824-46825 46827 46849-46851 48196-48197 48199 48216-48217 48219 48244-48245 48247 48424-48425 48427 48516-48517 48519 48536-48537 48539 48564-48565 48567 48616-48617 48619 48964-48965 48967 48984-48985 48987-48988https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/521/3384?format=asciiOpticalInfrareddefaultJ/MNRAS/521/3384/janngcPhotometry of selected VST ATLAS QSO in NGC Northern Galactic Cap released in 31/01/2023recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension of the object (J2000) (RA)degpos.eq.ra;meta.mainindexedDEJ2000Declination of the object (J2000) (DEC)degpos.eq.dec;meta.mainindexedSelThe selection as Priority 1, non-UVX, or extended that the object belongs in as explained in section 3(selection)src.classcharumag? VST ATLAS u-band Aperture 3 magnitude in the AB system (u_mag)magphot.mag;em.opt.Udoublenullablee_umag[]? Error on the VST ATLAS u-band Aperture 3 magnitude (u_err)magstat.error;phot.magdoublenullablegmagVST ATLAS g-band Aperture 3 magnitude in the AB system (g_mag)magphot.mag;em.opt.Bdoublee_gmag[]? Error on the VST ATLAS g-band Aperture 3 magnitude (g_err)magstat.error;phot.magdoublenullablermagVST ATLAS r-band Aperture 3 magnitude in the AB system (r_mag)magphot.mag;em.opt.Rdoublee_rmag? Error on the VST ATLAS r-band Aperture 3 magnitude (r_err)magstat.error;phot.magfloatnullableimag? VST ATLAS i-band Aperture 3 magnitude in the AB system (i_mag)magphot.mag;em.opt.Idoublenullablee_imag[]? Error on the VST ATLAS i-band Aperture 3 magnitude (i_err)magstat.error;phot.magdoublenullablezmag? VST ATLAS z-band Aperture 3 magnitude in the AB system (z_mag)magphot.mag;em.opt.Idoublenullablee_zmag[]? Error on the VST ATLAS z-band Aperture 3 magnitude (z_err)magstat.error;phot.magdoublenullableW1magNeo6 W1-band magnitude in the Vega system (W1_mag)magphot.mag;em.IR.3-4umdoublee_W1magError on the neo6 W1-band magnitude (W1_err)magstat.error;phot.magfloatW2mag? Neo6 W2-band magnitude in the Vega system (W2_mag_)magphot.mag;em.IR.4-8umdoublenullablee_W2mag? Error on the neo6 W2-band magnitude (W2_err)magstat.error;phot.magfloatnullablezphPhotometric redshift calculated using the ANNz2 algorithm (photo_z)src.redshiftdoubleShanks25Display the VLT Survey Telescope ATLAS DR4 of Shanks et al. 2015MNRAS.451.4238S, Cat. II/385meta.ref.urlcharSchlafly19Display the band-merged unWISE Catalog of Schlafly et al. 2019ApJS..240...30S, Cat. II/363meta.ref.urlchar2dFGRSDisplay the 2dF Galaxy Redshift Survey of 2dFGRS Team 2001MNRAS.328.1039C, Cat. VII/250meta.ref.urlcharDESDisplay the Dark Energy Survey dr1 and dr2 of Abott et al. 2018ApJS..239...18A, Cat. II/357, 2021ApJS..255...20A, Cat. II/371meta.ref.urlcharTimlin16Display the SpIES: the Spitzer IRAC Equatorial Survey of Timlin et al. 2016ApJS..225....1T, Cat. J/ApJS/225/1meta.ref.urlcharJ/MNRAS/521/3384/jansgcPhotometry of selected VST ATLAS QSO in SGC Northern Galactic Cap released in 31/01/2023rmagVST ATLAS r-band Aperture 3 magnitude in the AB system (r_mag)magphot.mag;em.opt.Rdoublee_rmag? Error on the VST ATLAS r-band Aperture 3 magnitude (r_err)magstat.error;phot.magfloatnullableimag? VST ATLAS i-band Aperture 3 magnitude in the AB system (i_mag)magphot.mag;em.opt.Idoublenullablee_imag[]? Error on the VST ATLAS i-band Aperture 3 magnitude (i_err)magstat.error;phot.magdoublenullablezmag? VST ATLAS z-band Aperture 3 magnitude in the AB system (z_mag)magphot.mag;em.opt.IdoublenullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension of the object (J2000) (RA)degpos.eq.ra;meta.mainindexedDEJ2000Declination of the object (J2000) (DEC)degpos.eq.dec;meta.mainindexedSelThe selection as Priority 1, non-UVX, or extended that the object belongs in as explained in section 3(selection)src.classcharumag? VST ATLAS u-band Aperture 3 magnitude in the AB system (u_mag)magphot.mag;em.opt.Udoublenullablee_umag[]? Error on the VST ATLAS u-band Aperture 3 magnitude (u_err)magstat.error;phot.magdoublenullablegmagVST ATLAS g-band Aperture 3 magnitude in the AB system (g_mag)magphot.mag;em.opt.Bdoublee_gmag[]? Error on the VST ATLAS g-band Aperture 3 magnitude (g_err)magstat.error;phot.magdoublenullablee_zmag[]? Error on the VST ATLAS z-band Aperture 3 magnitude (z_err)magstat.error;phot.magdoublenullableW1magNeo6 W1-band magnitude in the Vega system (W1_mag)magphot.mag;em.IR.3-4umdoublee_W1magError on the neo6 W1-band magnitude (W1_err)magstat.error;phot.magfloatW2mag? Neo6 W2-band magnitude in the Vega system (W2_mag_)magphot.mag;em.IR.4-8umdoublenullablee_W2mag? Error on the neo6 W2-band magnitude (W2_err)magstat.error;phot.magfloatnullablezphPhotometric redshift calculated using the ANNz2 algorithm (photo_z)src.redshiftdoubleShanks25Display the VLT Survey Telescope ATLAS DR4 of Shanks et al. 2015MNRAS.451.4238S, Cat. II/385meta.ref.urlcharSchlafly19Display the band-merged unWISE Catalog of Schlafly et al. 2019ApJS..240...30S, Cat. II/363meta.ref.urlchar2dFGRSDisplay the 2dF Galaxy Redshift Survey of 2dFGRS Team 2001MNRAS.328.1039C, Cat. VII/250meta.ref.urlcharDESDisplay the Dark Energy Survey dr1 and dr2 of Abott et al. 2018ApJS..239...18A, Cat. II/357, 2021ApJS..255...20A, Cat. II/371meta.ref.urlcharTimlin16Display the SpIES: the Spitzer IRAC Equatorial Survey of Timlin et al. 2016ApJS..225....1T, Cat. J/ApJS/225/1meta.ref.urlcharJ/MNRAS/521/3384/marngcPhotometry of selected VST ATLAS QSO in NGC Northern Galactic Cap released in 06/03/2023e_imag[]? Error on the VST ATLAS i-band Aperture 3 magnitude (i_err)magstat.error;phot.magdoublenullablezmag? VST ATLAS z-band Aperture 3 magnitude in the AB system (z_mag)magphot.mag;em.opt.Idoublenullablee_zmag[]? Error on the VST ATLAS z-band Aperture 3 magnitude (z_err)magstat.error;phot.magdoublenullableW1magNeo6 W1-band magnitude in the Vega system (W1_mag)magphot.mag;em.IR.3-4umdoublee_W1magError on the neo6 W1-band magnitude (W1_err)magstat.error;phot.magfloatW2mag? Neo6 W2-band magnitude in the Vega system (W2_mag_)magphot.mag;em.IR.4-8umdoublenullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension of the object (J2000) (RA)degpos.eq.ra;meta.mainindexedDEJ2000Declination of the object (J2000) (DEC)degpos.eq.dec;meta.mainindexedSelThe selection as Priority 1, non-UVX, or extended that the object belongs in as explained in section 3(selection)src.classcharumag? VST ATLAS u-band Aperture 3 magnitude in the AB system (u_mag)magphot.mag;em.opt.Udoublenullablee_umag[]? Error on the VST ATLAS u-band Aperture 3 magnitude (u_err)magstat.error;phot.magdoublenullablegmagVST ATLAS g-band Aperture 3 magnitude in the AB system (g_mag)magphot.mag;em.opt.Bdoublee_gmag[]? Error on the VST ATLAS g-band Aperture 3 magnitude (g_err)magstat.error;phot.magdoublenullablermagVST ATLAS r-band Aperture 3 magnitude in the AB system (r_mag)magphot.mag;em.opt.Rdoublee_rmag? Error on the VST ATLAS r-band Aperture 3 magnitude (r_err)magstat.error;phot.magfloatnullableimag? VST ATLAS i-band Aperture 3 magnitude in the AB system (i_mag)magphot.mag;em.opt.Idoublenullablee_W2mag? Error on the neo6 W2-band magnitude (W2_err)magstat.error;phot.magfloatnullablezphPhotometric redshift calculated using the ANNz2 algorithm (photo_z)src.redshiftdoubleShanks25Display the VLT Survey Telescope ATLAS DR4 of Shanks et al. 2015MNRAS.451.4238S, Cat. II/385meta.ref.urlcharSchlafly19Display the band-merged unWISE Catalog of Schlafly et al. 2019ApJS..240...30S, Cat. II/363meta.ref.urlchar2dFGRSDisplay the 2dF Galaxy Redshift Survey of 2dFGRS Team 2001MNRAS.328.1039C, Cat. VII/250meta.ref.urlcharDESDisplay the Dark Energy Survey dr1 and dr2 of Abott et al. 2018ApJS..239...18A, Cat. II/357, 2021ApJS..255...20A, Cat. II/371meta.ref.urlcharTimlin16Display the SpIES: the Spitzer IRAC Equatorial Survey of Timlin et al. 2016ApJS..225....1T, Cat. J/ApJS/225/1meta.ref.urlcharJ/MNRAS/521/3384/marsgcPhotometry of selected VST ATLAS QSO in SGC Northern Galactic Cap released in 06/03/2023W1magNeo6 W1-band magnitude in the Vega system (W1_mag)magphot.mag;em.IR.3-4umdoublee_W1magError on the neo6 W1-band magnitude (W1_err)magstat.error;phot.magfloatW2mag? Neo6 W2-band magnitude in the Vega system (W2_mag_)magphot.mag;em.IR.4-8umdoublenullablee_W2mag? Error on the neo6 W2-band magnitude (W2_err)magstat.error;phot.magfloatnullablezphPhotometric redshift calculated using the ANNz2 algorithm (photo_z)src.redshiftdoubleShanks25Display the VLT Survey Telescope ATLAS DR4 of Shanks et al. 2015MNRAS.451.4238S, Cat. II/385meta.ref.urlcharSchlafly19Display the band-merged unWISE Catalog of Schlafly et al. 2019ApJS..240...30S, Cat. II/363meta.ref.urlchar2dFGRSDisplay the 2dF Galaxy Redshift Survey of 2dFGRS Team 2001MNRAS.328.1039C, Cat. VII/250meta.ref.urlcharDESDisplay the Dark Energy Survey dr1 and dr2 of Abott et al. 2018ApJS..239...18A, Cat. II/357, 2021ApJS..255...20A, Cat. II/371meta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension of the object (J2000) (RA)degpos.eq.ra;meta.mainindexedDEJ2000Declination of the object (J2000) (DEC)degpos.eq.dec;meta.mainindexedSelThe selection as Priority 1, non-UVX, or extended that the object belongs in as explained in section 3(selection)src.classcharumag? VST ATLAS u-band Aperture 3 magnitude in the AB system (u_mag)magphot.mag;em.opt.Udoublenullablee_umag[]? Error on the VST ATLAS u-band Aperture 3 magnitude (u_err)magstat.error;phot.magdoublenullablegmagVST ATLAS g-band Aperture 3 magnitude in the AB system (g_mag)magphot.mag;em.opt.Bdoublee_gmag[]? Error on the VST ATLAS g-band Aperture 3 magnitude (g_err)magstat.error;phot.magdoublenullablermagVST ATLAS r-band Aperture 3 magnitude in the AB system (r_mag)magphot.mag;em.opt.Rdoublee_rmag? Error on the VST ATLAS r-band Aperture 3 magnitude (r_err)magstat.error;phot.magfloatnullableimag? VST ATLAS i-band Aperture 3 magnitude in the AB system (i_mag)magphot.mag;em.opt.Idoublenullablee_imag[]? Error on the VST ATLAS i-band Aperture 3 magnitude (i_err)magstat.error;phot.magdoublenullablezmag? VST ATLAS z-band Aperture 3 magnitude in the AB system (z_mag)magphot.mag;em.opt.Idoublenullablee_zmag[]? Error on the VST ATLAS z-band Aperture 3 magnitude (z_err)magstat.error;phot.magdoublenullableTimlin16Display the SpIES: the Spitzer IRAC Equatorial Survey of Timlin et al. 2016ApJS..225....1T, Cat. J/ApJS/225/1meta.ref.urlchar