The Gravitational Lensing Imprints of DES Y3 Superstructures on the CMB: A Matched Filtering Approach

$ $Lowdensitycosmicvoidsgravitationallylensthecosmicmicrowavebackground(CMB),leavinganegativeimprintontheCMBconvergence$κ$\mathrm{.}Thiseffectprovidesinsightintothedistributionofmatterwithinvoids,andcanalsobeusedtostudythegrowthofstructure\mathrm{.}Wemeasurethislensingimprintbycross-correlatingthePlanckCMBlensingconvergencemapwithvoidsidentifiedintheDarkEnergySurveyYear3dataset,coveringapproximately4,200deg$^2$ofthesky\mathrm{.}Weusetwodistinctvoid-findingalgorithms:a2Dvoid-finderwhichoperatesontheprojectedgalaxydensityfieldinthinredshiftshells,andanewcode,Voxel,whichoperatesonthefull3Dmapofgalaxypositions\mathrm{.}Weemployanoptimalmatchedfilteringmethodforcross-correlation,usingtheMICEN-bodysimulationbothtoestablishthetemplateforthematchedfilterandtocalibratedetectionsignificances\mathrm{.}UsingtheDESY3photometricluminousredgalaxysample,wemeasure$A_κ$,theamplitudeoftheobservedlensingsignalrelativetothesimulationtemplate,obtaining$A_κ= 1.03 \pm 0.22$($4.6σ$significance)forVoxeland$A_κ= 1.02 \pm 0.17$($5.9σ$significance)for2Dvoids,bothconsistentwith$Λ$CDMexpectations\mathrm{.}Weadditionallyinvertthe2Dvoid-findingprocesstoidentifysuperclustersintheprojecteddensityfield,forwhichwemeasure$A_κ= 0.87 \pm 0.15$($5.9σ$ significance). The leading source of noise in our measurements is Planck noise, implying that future data from the Atacama Cosmology Telescope (ACT), South Pole Telescope (SPT) and CMB-S4 will increase sensitivity and allow for more precise measurements.