auto c = new TCanvas("", "",0,0,1100,550);
c->Divide(2,1);
gStyle->SetOptStat(0);

auto h1 = new TH2D("h1","h1",40,-4,4,40,-20,20);
auto h2 = new TH2D("h2","h2",40,-4,4,40,-20,20);
float px, py;
for (int i = 0; i < 25000; i++) {
   gRandom->Rannor(px,py); h1->Fill(px,5*py);
   gRandom->Rannor(px,py); h2->Fill(px,5*py);
}

TPad *p1 = (TPad *)c->cd(1);
TPad *p2 = (TPad *)c->cd(2);

p1->SetRightMargin(0.15);
auto palette1 = new TPaletteAxis(4.05,-15,4.5,15,h1);
h1->GetListOfFunctions()->Add(palette1);

p2->SetBottomMargin(0.2);
auto palette2 = new TPaletteAxis(-3.,-25,3.,-23,h2);
h2->GetListOfFunctions()->Add(palette2);

p1->cd(); h1->Draw("colz");
p2->cd(); h2->Draw("colz");

gROOT->GetListOfCanvases()->Draw()