When I combine Labeled with Rasterize the Labels get scaled wrong

I’m trying to create a high quality image for a publication, I am combining two plots, with a legend, and labeled using the Labeled command, I then use Rasterize to make it a single image so I can put it in LaTeX. Just in Mathematica using

op2 = ListLinePlot[{output1a1, output2a1, output1b1, output2b1}, 
   TicksStyle -> Directive[Medium, Bold], PlotMarkers -> Automatic, 
   PlotLegends -> {"PU1 Right", "PU1 Left", "PU2 Right", "PU2 Left"}, 
   ImageSize -> Large];
fr[x] := 0.75*3.599*10^-7;
op3a = Plot[(10^6)*fr[x], {x, 0, 37500}];
ar1 = Show[{op2, op3a}]
ar2 = Labeled[
  ar1, {"Carbon Turns " <> turnstring, 
   "Overlap Parameter ([Mu]s)"}, {Bottom, Left}, RotateLabel -> True]

I get what I was expecting,

But When I try to rasterize it using either:

p1 = Rasterize[
  Labeled[ar1, {"Carbon Turns " <> turnstring, 
    "Overlap Parameter ([Mu]s)", "Constrained"}, {Bottom, Left, Top},
    RotateLabel -> True, LabelStyle -> "Medium"], 
  ImageResolution -> 600]
p2 = Rasterize[ar2, ImageResolution -> 600]

I get

How do I get it to display properly?