import yt
ds = yt.load('TipsyGalaxy/galaxy.00300')
ad = ds.all_data()
cr = ad.cut_region("obj['gas', 'temperature'] < 1e3")
yt.ProjectionPlot(ds, 'z', ('gas', 'density'), width=(100, 'kpc'), center='m')
/Users/goldbaum/Documents/yt-hg/yt/data_objects/octree_subset.py:203: RuntimeWarning: invalid value encountered in divide vals = op.finalize()
yt.ProjectionPlot(ds, 'z', ('gas', 'density'), data_source=cr, width=(100, 'kpc'), center='m')
yt.SlicePlot(ds, 'z', ('gas', 'temperature'), width=(100, 'kpc'), center='m')