Low-mass halo perturbations in strong gravitational lenses at redshift z$sim$0.5 are consistent with CDM. (arXiv:1811.03627v1 [astro-ph.CO])
<a href="http://arxiv.org/find/astro-ph/1/au:+Ritondale_E/0/1/0/all/0/1">E. Ritondale</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vegetti_S/0/1/0/all/0/1">S. Vegetti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Despali_G/0/1/0/all/0/1">G. Despali</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Auger_M/0/1/0/all/0/1">M. W. Auger</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Koopmans_L/0/1/0/all/0/1">L. V. E Koopmans</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+McKean_J/0/1/0/all/0/1">J. P. McKean</a>
We use a sample of 17 strong gravitational lens systems from the BELLS
GALLERY survey to quantify the amount of low-mass dark matter haloes within the
lensing galaxies and along their lines of sight, and to constrain the
properties of dark matter. Based on a detection criterion of 10$sigma$, we
report no significant detection in any of the lenses. Using the sensitivity
function at the 10-$sigma$ level, we have calculated the predicted number of
detectable cold dark matter (CDM) line-of-sight haloes to be $mu_{l} =
1.17pm1.08$, in agreement with our null detection. Assuming a detection
sensitivity that improved to the level implied by a 5-$sigma$ threshold, the
expected number of detectable line-of-sight haloes rises to $mu_l =
9.0pm3.0$. Whilst the current data find zero detections at this sensitivity
level (which has a probability of P$^{{rm5}sigma}_{{rm CDM}}(n_{rm
det}=0)$=0.0001 and would be in strong tension with the CDM framework), we find
that such a low detection threshold leads to many spurious detections and
non-detections and therefore the current lack of detections is unreliable and
requires data with improved sensitivity. Combining this sample with a subsample
of 11 SLACS lenses, we constrain the half-mode mass to be $log$(M$_{rm hm}) <
12.26$ at the 2-$sigma$ level. The latter is consistent with resonantly
produced sterile neutrino masses m$_{rm s} < 0.8$ keV at any value of the
lepton asymmetry at the 2-$sigma$ level.
We use a sample of 17 strong gravitational lens systems from the BELLS
GALLERY survey to quantify the amount of low-mass dark matter haloes within the
lensing galaxies and along their lines of sight, and to constrain the
properties of dark matter. Based on a detection criterion of 10$sigma$, we
report no significant detection in any of the lenses. Using the sensitivity
function at the 10-$sigma$ level, we have calculated the predicted number of
detectable cold dark matter (CDM) line-of-sight haloes to be $mu_{l} =
1.17pm1.08$, in agreement with our null detection. Assuming a detection
sensitivity that improved to the level implied by a 5-$sigma$ threshold, the
expected number of detectable line-of-sight haloes rises to $mu_l =
9.0pm3.0$. Whilst the current data find zero detections at this sensitivity
level (which has a probability of P$^{{rm5}sigma}_{{rm CDM}}(n_{rm
det}=0)$=0.0001 and would be in strong tension with the CDM framework), we find
that such a low detection threshold leads to many spurious detections and
non-detections and therefore the current lack of detections is unreliable and
requires data with improved sensitivity. Combining this sample with a subsample
of 11 SLACS lenses, we constrain the half-mode mass to be $log$(M$_{rm hm}) <
12.26$ at the 2-$sigma$ level. The latter is consistent with resonantly
produced sterile neutrino masses m$_{rm s} < 0.8$ keV at any value of the
lepton asymmetry at the 2-$sigma$ level.
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