1702.00009
Lensing substructure quantification in RXJ1131-1231: A 2 keV lower bound on dark matter thermal relict mass
Birrer, Amara, Refregier
Study the substructure content of the SL RXJ1131-1231 through a forward modelling approach that relies on generating an extensive suite of realistic sims. The statistics of the substructure population of haloes depends on the properties of DM. Use a merger tree prescription that allows to stochastically generate substructure populations whose properties depend on the DM particle mass. These synthetic haloes are then used as lenses to produce realistic mock images that have the same features, e.g. luminous arcs, quasar positions, instrumental noise and PSF, as the data. By analyzing the data and the simulations in the same way, able to constrain models of DM statistically using Approximate Bayesian Computing techniques. This method relies on constructing summary statistics and distance measures that are sensitive to the signal being targeted. Find that using the HST data for RXJ, able to rule out a warm dark matter thermal relict mass below 2 keV at the 2 sigma CL.
1702.00072
Discovery of the lensed quasar system DES J0408-5354
Lin et al
Discovery of DES J04048-5354 in DES Y1 data: discovered using a search for DES Y1 SL systems using a method that identified candidates as red galaxies with multiple blue neighbors. It consists of a central red galaxy surrounded by 3 bright (i<20) blue objects and a fourth red object. Subsequent spectroscopic observations using Gemini South confirmed that the 3 blue objects are indeed the lensed images of a quasar with z-2.375, and that the central red object is an early-type lensing galaxy with z=0.597. It is the first quad lensed quasar system to be found in DES and begins to demonstrate the potential of DES to discover and dramatically increase the sample size of these rare objects.
Lensing substructure quantification in RXJ1131-1231: A 2 keV lower bound on dark matter thermal relict mass
Birrer, Amara, Refregier
Study the substructure content of the SL RXJ1131-1231 through a forward modelling approach that relies on generating an extensive suite of realistic sims. The statistics of the substructure population of haloes depends on the properties of DM. Use a merger tree prescription that allows to stochastically generate substructure populations whose properties depend on the DM particle mass. These synthetic haloes are then used as lenses to produce realistic mock images that have the same features, e.g. luminous arcs, quasar positions, instrumental noise and PSF, as the data. By analyzing the data and the simulations in the same way, able to constrain models of DM statistically using Approximate Bayesian Computing techniques. This method relies on constructing summary statistics and distance measures that are sensitive to the signal being targeted. Find that using the HST data for RXJ, able to rule out a warm dark matter thermal relict mass below 2 keV at the 2 sigma CL.
1702.00072
Discovery of the lensed quasar system DES J0408-5354
Lin et al
Discovery of DES J04048-5354 in DES Y1 data: discovered using a search for DES Y1 SL systems using a method that identified candidates as red galaxies with multiple blue neighbors. It consists of a central red galaxy surrounded by 3 bright (i<20) blue objects and a fourth red object. Subsequent spectroscopic observations using Gemini South confirmed that the 3 blue objects are indeed the lensed images of a quasar with z-2.375, and that the central red object is an early-type lensing galaxy with z=0.597. It is the first quad lensed quasar system to be found in DES and begins to demonstrate the potential of DES to discover and dramatically increase the sample size of these rare objects.
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