J/A+A/703/A17ivo://CDS.VizieR/J/A+A/703/A17CDSHerwig E.Arrigoni Battaia F.Chen C.-C.Obreja A.Nowotka M.,Remus R.-S.Yajima H.2026-03-02T06:25:50Z2025-10-31T07:17:45ZCDS support team

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

cds-question@unistra.frgalaxy-clustersmillimeter-astronomysubmillimeter-astronomyquasarsA commonly employed method to detect protoclusters in the young universe is the search for overdensities of massive star forming galaxies, such as submillimeter galaxies (SMGs), around high-mass halos, including those hosting quasars. In this work, we study the Megaparsec environment surrounding nine physically associated quasar pairs between z=2.45 and z=3.82 with JCMT/SCUBA-2 observations at 450{mu}m and 850{mu}m covering a field of view of roughly 13.7 arcmin in diameter (or 32Mpc^2^ at the median redshift) for each system. We identify a total of 170 SMG candidates and 26 non-SMG and interloper candidates. A comparison of the underlying 850{mu}m source models recovered with Monte Carlo simulations to the blank field model reveals galaxy overdensities in all fields, with a weighted average overdensity factor of delta_cumul_=3.4+/-0.3. From this excess emission at 850{mu}m, we calculate a star formation rate density of 1700+/-100M_{sun}_/yr/Mpc^3^, consistent with predictions from protocluster simulations and observations. Compared to fields around single quasars, those surrounding quasar pairs have higher excess counts and more centrally peaked star formation, further highlighting the co-evolution of SMGs and quasars. We do not find preferential alignment of the SMGs with the quasar pair direction or their associated Ly{alpha} nebulae, indicating that cosmic web filaments on different scales might be traced by the different directions. Overall, this work substantiates the reliability of quasar pairs to detect overdensities of massive galaxies and likely sites of protocluster formation. Future spectroscopic follow-up observations are needed to confirm membership of the SMG candidates with the physically associated quasar pairs and definitively identify the targeted fields as protoclusters.2025A&A...703A..17Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/703/A17CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/703/A17https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/703/A17http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/703/A17https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/703/A17https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/703/A17http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/703/A17GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/703/A17/tableb (Interloper and non-SMG candidates in the quasar pair fields based on the 450{mu}m to 850{mu}m flux ratio (table B1))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/703/A17/tableb?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/703/A17/tableb?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/703/A17/tableb?GETtext/xml+votable180.050000true0.4520837.0871670.005555555555555556Cone search capability for table J/A+A/703/A17/tablec (SMG candidates in the quasar pair fields (tables C1-C9))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/703/A17/tablec?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/703/A17/tablec?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/703/A17/tablec?GETtext/xml+votable180.050000true0.4441677.1093890.0055555555555555566/17741 17743 17752-17753 18015 18040 19510 19848 27255 27261 27426 27432 27549 315462.3390025583187276e-22 4.414320791325542e-22https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/703/A17?format=asciiMillimeterdefaultJ/A+A/703/A17/tablebInterloper and non-SMG candidates in the quasar pair fields based on the 450{mu}m to 850{mu}m flux ratio (table B1)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameInterloper namemeta.id;meta.maincharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainePos? Error on Positionarcsecstat.error;posfloatnullableF850Flux density at 850ummJyphot.flux.density;em.mm.200-400GHzfloate_F850Error on flux density at 850ummJystat.errorfloatF850D? Deboosted flux density at 850ummJyphot.flux.density;em.mm.200-400GHzfloatnullablee_F850D? Error on Deboosted flux density at 850ummJystat.errorfloatnullableF450Flux density at 450ummJyphot.flux.density;em.mm.400-750GHzfloate_F450Error on flux density at 450ummJystat.errorfloatF450D? Deboosted flux density at 450ummJyphot.flux.density;em.mm.400-750GHzfloatnullablee_F450D? Error on Deboosted flux density at 450ummJystat.errorfloatnullableJ/A+A/703/A17/tablecSMG candidates in the quasar pair fields (tables C1-C9)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFieldTable number (C1-C9)obs.fieldcharNameSMG candidate namemeta.id;meta.maincharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainePos? Error on Positionarcsecstat.error;posfloatnullableF850Flux density at 850ummJyphot.flux.density;em.mm.200-400GHzfloate_F850Error on flux density at 850ummJystat.errorfloatF850D? Deboosted flux density at 850ummJyphot.flux.density;em.mm.200-400GHzfloatnullablee_F850D? Error on Deboosted flux density at 850ummJystat.errorfloatnullableforced[y/n] Forced flux at 450 um flag (y=yes, n=no)meta.codecharF450Flux density at 450ummJyphot.flux.density;em.mm.400-750GHzfloate_F450Error on flux density at 450ummJystat.errorfloatF450D? Deboosted flux density at 450ummJyphot.flux.density;em.mm.400-750GHzfloatnullablee_F450D? Error on Deboosted flux density at 450ummJystat.errorfloatnullable