II/391ivo://CDS.VizieR/II/391CDSChang S.-W.Im M.Jeong M.Kim J.Park B.Lee J.Buckley D.A.H.,Cooke J.Jung S.Kim D.-J.Kim J.H.Kim Y.Lee C.-U.Lee S.-K.,Paek G.S.H.Shin J.2026-05-11T07:12:40Z2026-05-04T09:07:51ZCDS support team

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

cds-question@unistra.frinfrared-photometryvisible-astronomybroad-band-photometrysurveysWe present the first public data release (DR1) of the KMTNet Synoptic Survey of Southern Sky (KS4). This deep, wide-field imaging survey covers a southern footprint of -85{deg}<DEC<-28.8{deg} in the B, V, R, and I bands using a network of three 1.6-m telescopes. Although primarily designed to secure reference imaging for gravitational wave counterpart identification, DR1 delivers science-ready data for ~4000deg2 to enable a broad range of astrophysical research. The release includes deep co-added images reaching median 5{sigma} depths of 22.0-23.5 AB mag. It is accompanied by two source catalogs containing over 200 million sources with SNR>5: an I-band-selected forced-photometry catalog optimized for consistent colors, and a band-merged catalog offering enhanced completeness. Validation demonstrates robust data quality, characterized by mean astrometric offsets of +0.054+/-0.129arcsec in RA and -0.015+/-0.120arcsec in DEC relative to Gaia DR3. Photometric uniformity for point sources is maintained within +/-0.03mag relative to Gaia XP for 97.5-99.8% of the footprint across all four bands. A key advantage of KS4 is its uniform and contiguous spatial coverage. It extends to fainter magnitudes than other uniform surveys while filling irregular gaps in existing deep datasets.2026JKAS...59..179Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/II/391CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)II/367 : The VISTA Hemisphere Survey (VHS) catalog DR5 (McMahon+, 2020)II/336 : AAVSO Photometric All Sky Survey (APASS) DR9 (Henden+, 2016)II/371 : The Dark Energy Survey (DES): Data Release 2 (Abbott+, 2021)J/PASP/110/863 : A Stellar Spectral Flux Library: 1150 - 25000 A (Pickles 1998)J/PASP/124/140 : UBVRI Hp BT and VT photonic responses (Bessell+, 2012)J/ApJ/916/47 : GECKO follow-up obs. of 3 binary BH GW events (Kim+, 2021)J/ApJS/275/46 : Unobscured QSO cand. in the southern sky with KS4 (Kim+, 2024)http://datalab.noirlab.edu/data/ks4 : KS4 data at NOIRLab'shttp://alasky.cds.unistra.fr/KS4/DR1 : KS4 images in Aladinhttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=II/391https://vizier.iucaa.in/viz-bin/VizieR-2?-source=II/391http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=II/391https://vizier.cds.unistra.fr/viz-bin/votable?-source=II/391https://vizier.iucaa.in/viz-bin/votable?-source=II/391http://vizieridia.saao.ac.za/viz-bin/votable?-source=II/391GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table II/391/ks4dr1 (*the band-merged single_master catalog (1000 among 279,909,360 sources))https://vizier.cds.unistra.fr/viz-bin/conesearch/II/391/ks4dr1?https://vizier.iucaa.in/viz-bin/conesearch/II/391/ks4dr1?http://vizieridia.saao.ac.za/viz-bin/conesearch/II/391/ks4dr1?GETtext/xml+votable180.050000true60.781526215-72.8386735430.0055555555555555560/0-11 6/https://cdsarc.cds.unistra.fr/viz-bin/moc/II/391?format=asciiOpticalInfrareddefaultII/391/ks4dr1*the band-merged single_master catalog (1000 among 279,909,360 sources)Vmag3? Aperture magnitude (3 arcsec) in band V (mag_aper3_v)magphot.mag;em.opt.VfloatnullablePA-V[-90/90]? Position angle in band V (theta_image_v)degpos.posAng;em.opt.VfloatnullableCoaddIDUnique object identifier (coadd_object_id)meta.id;meta.mainindexedRAJ2000Right Ascension (J2000) (ra)degpos.eq.ra;meta.mainDEJ2000[-85.1/-28.7] Declination (J2000) (dec)degpos.eq.dec;meta.mainHealpixHEALPix index for sky position (healpix_index)meta.idlongNdet[1/12] Number of detections across all KS4 tiles (n_det)meta.numberintGLONGalactic longitude (glon)degpos.galactic.lonGLAT[-87.3/34.1] Galactic latitude (glat)degpos.galactic.latdoubleE(B-V)[0.007/16.3] E(B-V) extinction from Schlegel+ (1998ApJ...500..525S) using the dustmap tool (ebmv_sfd)magphot.color.excessdoubleb_MJD-V? Minimum Modified Julian Date in band V (min_mjd_v)dstat.min;time.epoch;em.opt.Vdoublenullableb_MJD-R? Minimum Modified Julian Date in band R (min_mjd_r)dstat.min;time.epoch;em.opt.Rdoublenullableb_MJD-I? Minimum Modified Julian Date in band I (min_mjd_i)dstat.min;time.epoch;em.opt.IdoublenullableB_MJD-B? Maximum Modified Julian Date in band B (max_mjd_b)dstat.max;time.epoch;em.opt.BdoublenullableB_MJD-V? Maximum Modified Julian Date in band V (max_mjd_v)dstat.max;time.epoch;em.opt.VdoublenullableB_MJD-R? Maximum Modified Julian Date in band R (max_mjd_r)dstat.max;time.epoch;em.opt.RdoublenullableB_MJD-I? Maximum Modified Julian Date in band I (max_mjd_i)dstat.max;time.epoch;em.opt.IdoublenullableMJD-B? Mean Modified Julian Date in band B (mean_mjd_b)dtime.epoch;em.opt.BdoublenullableMJD-V? Mean Modified Julian Date in band V (mean_mjd_v)dtime.epoch;em.opt.VdoublenullableMJD-R? Mean Modified Julian Date in band R (mean_mjd_r)dtime.epoch;em.opt.RdoublenullableMJD-I? Mean Modified Julian Date in band I (mean_mjd_i)dtime.epoch;em.opt.IdoublenullableBmag[-23.96/26.85]? SExtractor AUTO magnitude in band B (mag_auto_b)magphot.mag;em.opt.Bdoublenullableindexede_Bmag[0/0.5]? Uncertainty on Bmag (magerr_auto_b)magstat.error;phot.mag;em.opt.BfloatnullableVmag[4.6/25.31]? SExtractor AUTO magnitude in band V (mag_auto_v)magphot.mag;em.opt.Vfloatnullableindexede_Vmag[0/0.5]? Uncertainty on Vmag (magerr_auto_v)magstat.error;phot.mag;em.opt.VfloatnullableRmag[-10.96/25.51]? SExtractor AUTO magnitude in band R (mag_auto_r)magphot.mag;em.opt.Rdoublenullableindexede_Rmag[0/0.5]? Uncertainty on Rmag (magerr_auto_r)magstat.error;phot.mag;em.opt.RfloatnullableImag[-18.91/25.7]? SExtractor AUTO magnitude in band I (mag_auto_i)magphot.mag;em.opt.Idoublenullableindexede_Imag[0/0.5]? Uncertainty on Imag (magerr_auto_i)magstat.error;phot.mag;em.opt.IfloatnullableBmag3[-23.64/26.83]? Aperture magnitude (3 arcsec) in band B (mag_aper3_b)magphot.mag;em.opt.Bdoublenullablee_Bmag3[0/0.5]? Bmag3 uncertainty (magerr_aper3_b)magstat.error;phot.mag;em.opt.Bfloatnullablee_Vmag3[0/0.5]? Vmag3 uncertainty (magerr_aper3_v)magstat.error;phot.mag;em.opt.VfloatnullableRmag3? Aperture magnitude (3 arcsec) in band R (mag_aper3_r)magphot.mag;em.opt.Rdoublenullablee_Rmag3[0/0.5]? Rmag3 uncertainty (magerr_aper3_r)magstat.error;phot.mag;em.opt.RfloatnullableImag3? Aperture magnitude (3 arcsec) in band I (mag_aper3_i)magphot.mag;em.opt.Idoublenullablee_Imag3[0/0.5]? Imag3 uncertainty (magerr_aper3_i)magstat.error;phot.mag;em.opt.IfloatnullableBmag5? Aperture magnitude (5 arcsec) in band B (mag_aper5_b)magphot.mag;em.opt.Bdoublenullablee_Bmag5[0/0.5]? Bmag5 uncertainty (magerr_aper5_b)magstat.error;phot.mag;em.opt.BfloatnullableVmag5? Aperture magnitude (5 arcsec) in band V (mag_aper5_v)magphot.mag;em.opt.Vfloatnullablee_Vmag5[0/0.5]? Vmag5 uncertainty (magerr_aper5_v)magstat.error;phot.mag;em.opt.VfloatnullableRmag5? Aperture magnitude (5 arcsec) in band R (mag_aper5_r)magphot.mag;em.opt.Rdoublenullablee_Rmag5[0/0.5]? Rmag5 uncertainty (magerr_aper5_r)magstat.error;phot.mag;em.opt.RfloatnullableImag5? Aperture magnitude (5 arcsec) in band I (mag_aper5_i)magphot.mag;em.opt.Idoublenullablee_Imag5[0/0.5]? Imag5 uncertainty (magerr_aper5_i)magstat.error;phot.mag;em.opt.IfloatnullableBmag10[-24/27]? Aperture magnitude (10") in band B (mag_aper10_b)magphot.mag;em.opt.Bdoublenullablee_Bmag10[0/0.5]? Bmag10 uncertainty (magerr_aper10_b)magstat.error;phot.mag;em.opt.BfloatnullableVmag10[4.8/26.4]? Aperture magnitude (10") in band V (mag_aper10_v)magphot.mag;em.opt.Vfloatnullablee_Vmag10[0/0.5]? Vmag10 uncertainty (magerr_aper10_v)magstat.error;phot.mag;em.opt.VfloatnullableRmag10[-12/26.5]? Aperture magnitude (10") in band R (mag_aper10_r)magphot.mag;em.opt.Rdoublenullablee_Rmag10[0/0.5]? Rmag10 uncertainty (magerr_aper10_r)magstat.error;phot.mag;em.opt.RfloatnullableImag10[-18/25.5]? Aperture magnitude (10") in band I (mag_aper10_i)magphot.mag;em.opt.Idoublenullablee_Imag10[0/0.5]? Imag10 uncertainty (magerr_aper10_i)magstat.error;phot.mag;em.opt.IfloatnullableFWHM-B