Context : Deepfar-infrared ( FIR ) cosmologicalsurveysareknowntobeaffectedbysourceconfusion , causingissueswhenexaminingthemainsequence ( MS ) ofstarforminggalaxies.Inthepastthishastypicallybeenpartiallytackledbytheuseofstacking.However , stackingonlyprovidestheaveragepropertiesoftheobjectsinthestack .

Aims : ThisworkaimstotracetheMSover 0.2 \leq z < 6.0 usingthelatestde-blended Herschel photometry , whichreaches \approx 10 timesdeeperthanthe5 \sigma confusionlimitinSPIRE.Thisprovidesmorereliablestarformationrates ( SFRs ) , especiallyforthefaintergalaxies , andhenceamorereliableMS .

Methods : Webuiltapipelinethatusesthespectralenergydistribution ( SED ) modellingandfittingtoolCIGALEtogeneratefluxdensitypriorsinthe Herschel SPIREbands.Thesepriorswerethenfedintothede-blendingtoolXID+toextractfluxdensitiesfromtheSPIREmaps.Inthefinalstep , multi-wavelengthdatawerecombinedwiththeextractedSPIREfluxdensitiestoconstrainSEDsandprovidestellarmass ( M _ { \star } ) andSFRs.TheseM _ { \star } andSFRswerethenusedtopopulatetheSFR-M _ { \star } planeover 0.2 \leq z < 6.0 .

Results : Nosignificantevidenceofahigh-massturn-overwasfound ; thebestfitisthusasimpletwo-parameterpowerlawoftheform \log ( \mathrm { SFR } ) = \alpha [ \log ( \mathrm { M } _ { \star } ) -10.5 ] + \beta .Thenormalisationofthepowerlawincreaseswithredshift , rapidlyat z \lesssim 1.8 , from 0.58 \pm 0.09 at z \approx 0.37 to 1.31 \pm 0.08 at z \approx 1.8 .Theslopeisalsofoundtoincreasewithredshift , perhapswithanexcessaround 1.8 \leq z < 2.9 .

Conclusions : Theincreasingslopeindicatesthatgalaxiesbecomemoreself-similarasredshiftincreases.ThisimpliesthatthespecificSFRofhigh-massgalaxiesincreaseswithredshift , from0.2to6.0 , becomingclosertothatoflow-massgalaxies.Theexcessintheslopeat 1.8 \leq z < 2.9 , ifpresent , coincideswiththepeakofthecosmicstarformationhistory .