diff --git a/bilby/gw/conversion.py b/bilby/gw/conversion.py
index 399df6ca491c990aff35418a0d7d2fe8911536a3..faa4ea54008f7ca48f7c937f09abf32c82f360c3 100644
--- a/bilby/gw/conversion.py
+++ b/bilby/gw/conversion.py
@@ -2,8 +2,9 @@ from __future__ import division
 
 import numpy as np
 
-import pandas as pd
 from ..core.utils import logger, solar_mass
+from ..core.prior import DeltaFunction
+
 try:
     from astropy.cosmology import z_at_value, Planck15
     import astropy.units as u
@@ -17,7 +18,6 @@ except ImportError:
     logger.warning("You do not have lalsuite installed currently. You will"
                    " not be able to use some of the prebuilt functions.")
 
-from ..core.prior import DeltaFunction
 
 
 def redshift_to_luminosity_distance(redshift):