Fix alpha of checkpoint plot

bilby/core/sampler/ptemcee.py

@@ -616,7 +616,7 @@ def plot_walkers(walkers, nburn, thin, parameter_labels, outdir, label):
     nwalkers, nsteps, ndim = walkers.shape
     idxs = np.arange(nsteps)
     fig, axes = plt.subplots(nrows=ndim, ncols=2, figsize=(8, 3 * ndim))
-    scatter_kwargs = dict(lw=0, marker="o", markersize=1)
+    scatter_kwargs = dict(lw=0, marker="o", markersize=1, alpha=0.05,)
     # Plot the burn-in
     for i, (ax, axh) in enumerate(axes):
         ax.plot(