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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
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SEQUENCE:2
UID:UW-Physics-Event-8511
DTSTART:20231212T200000Z
DTEND:20231213T000000Z
DTSTAMP:20260412T150150Z
LAST-MODIFIED:20231211T135644Z
LOCATION:B343 Sterling
SUMMARY:Synthetic Source Injection in The Dark Energy Survey: Measurem
 ents of the Survey Transfer Function and Applications to Precision Cos
 mology\, Thesis Defense\, Megan Tabbutt\, Physics PhD Graduate Student
DESCRIPTION:Presented here is the Dark Energy Survey’s (DES) Synthet
 ic Source Injection (SSI) methodology and applications to precision co
 smology for our Y6 analysis of large-scale structure. Our methodology 
 is predicated on injecting models of real objects obtained from our ve
 ry high signal-to-noise Deep Field observations into our single-epoch 
 wide field images Both of which are critical to the measurements of th
 e three 2-point correlation functions\, cosmic shear\, galaxy clusteri
 ng and galaxy-galaxy lensing\, from which we constrain cosmological pa
 rameters. This methodology was introduced for our Y3 analysis\, and wa
 s the first example of using SSI to directly calibrate the cosmologica
 l measurements from a WF survey. The refinement and expansion of the m
 ethodology is presented here. Specifically\, we improved our mirroring
  of the WF image processing pipeline to now fully recreate it. We refa
 ctored our code-base to be able to run our SSI at multiple super-compu
 ting centers\, minimizing wall time and maximizing allocations. We als
 o developed a new injection scheme that injects sources which are pref
 erentially more useful to the cosmological analyses. These as well as 
 other updates\, our initial Y6 SSI results\, and their applications to
  precision cosmology will be discussed at length in this thesis. which
  are then processed identically to the original wide images. Inherent 
 to this methodology\, is that the synthetic sources automatically inhe
 rit the same systematics of the real wide field data\, a highly sought
  after achievement for many systematics modeling pipelines that is nea
 rly impossible to achieve from forward modeling techniques alone. In t
 he end\, we obtain wide field photometry catalogs of the deep field ob
 jects including their inheritance of the systematics. These catalogs a
 re a Monte Carlo sampling of the transfer function of the survey and c
 an be used for calibration and diagnostics\, as well as aid in the cal
 culation and validation of our 3x2pt analysis and consequentially our 
 measurement of cosmological parameter constraints. Specifically\, thro
 ugh the photometric redshift calibration of the weak lensing sources a
 nd the magnification bias estimate for the lens galaxy samples. 
URL:https://www.physics.wisc.edu/events/?id=8511
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