L1 detector orientation

The L1 detector orientation in https://git.ligo.org/lscsoft/bilby/-/blob/master/bilby/gw/detector/detectors/L1.interferometer does not include the arm tilts. This gives rise to differences of approximately 0.0003 in the antenna pattern compared to LAL.

If I run

import numpy as np
import time
import bilby
import lal
import lalsimulation

ifos = bilby.gw.detector.InterferometerList(["L1"])
ifo = ifos[0]
gpstime = 1305303144
trial = 100

fp_lal, fp_bilby, fc_lal, fc_bilby = [], [], [], []
for i in range(trial):
    ra, dec, psi = 2. * np.pi * np.random.uniform(), np.pi * np.random.uniform() - np.pi / 2., np.pi * np.random.uniform()
    fplus, fcross = ifo.antenna_response(ra, dec, gpstime, psi, "plus"), ifo.antenna_response(ra, dec, gpstime, psi, "cross")
    fp_bilby.append(fplus)
    fc_bilby.append(fcross)
    gmst = lal.GreenwichMeanSiderealTime(gpstime)
    fplus, fcross = lal.ComputeDetAMResponse(lalsimulation.DetectorPrefixToLALDetector("L1").response, ra, dec, psi, gmst)
    fp_lal.append(fplus)
    fc_lal.append(fcross)

print(np.std(np.array(fc_bilby) - np.array(fc_lal)))
print(np.std(np.array(fp_bilby) - np.array(fp_lal)))

I get

0.00032833988847648507
0.0002990699021891997

whereas for H1 this is ~ 10^{-8}.

The discrepancy goes away when I set

xarm_tilt = -0.0003121
yarm_tilt = -0.0006107

following https://dcc.ligo.org/LIGO-T980044/public.