258 research outputs found
Cosmic Shear with Einstein Rings
We explore a new technique to measure cosmic shear using Einstein rings. In
Birrer et al. (2017), we showed that the detailed modelling of Einstein rings
can be used to measure external shear to high precision. In this letter, we
explore how a collection of Einstein rings can be used as a statistical probe
of cosmic shear. We present a forecast of the cosmic shear information
available in Einstein rings for different strong lensing survey configurations.
We find that, assuming that the number density of Einstein rings in the COSMOS
survey is representative, future strong lensing surveys should have a
cosmological precision comparable to the current ground based weak lensing
surveys. We discuss how this technique is complementary to the standard cosmic
shear analyses since it is sensitive to different systematic and can be used
for cross-calibration.Comment: 4 pages, 1 figure, 1 table. ApJL accepte
Searching for dark matter substructure: a deeper wide-area community survey for Roman
We recommend a deeper extension to the High-Latitute Wide Area Survey planned
to be conducted by the Nancy Grace Roman Space Telescope (\emph{Roman}). While
this deeper-tier survey extension can support a range of astrophysical
investigations, it is particularly well suited to characterize the dark matter
substructure in galactic halos and reveal the microphysics of dark matter
through gravitational lensing. We quantify the expected yield of \emph{Roman}
for finding galaxy-galaxy-type gravitational lenses and motivate observational
choices to optimize the \emph{Roman} core community surveys for studying dark
matter substructure. In the proposed survey, we expect to find, on average, one
strong lens with a characterizable substructure per \emph{Roman} tile (0.28
squared degrees), yielding approximately 500 such high-quality lenses. With
such a deeper legacy survey, \emph{Roman} will outperform any current and
planned telescope within the next decade in its potential to characterize the
concentration and abundance of dark matter subhalos in the mass range
10-10\,M.Comment: 5 pages, 3 figures, Roman Core Community Survey (CCS) White Pape
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