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PRODID:UW-Madison-Physics-Events
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UID:UW-Physics-Event-9341
DTSTART:20250808T190000Z
DTEND:20250808T210000Z
DTSTAMP:20260413T084054Z
LAST-MODIFIED:20250725T212951Z
LOCATION:B343 Sterling or https://uwmadison.zoom.us/j/7100151594?pwd=I
 oiSX32HmHbnwFU0KHsIjOeQm7f0FE.1&omn=92298395192
SUMMARY:Synthetic source injection in photometric surveys for cosmolog
 y\, Preliminary Exam\, Julian Beas-Gonzalez\, Physics PhD Graduate Stu
 dent
DESCRIPTION:Synthetic source injection (SSI) is an extremely useful te
 chnique for the validation of photometric survey data. It consists in 
 artificially inserting objects\, such as galaxies and stars\, with wel
 l-known properties into real astronomical images. By processing images
  with injected sources\, we can obtain measurements of the observed pr
 operties of these sources and compare them to their true properties. T
 he transfer function between observed and true values allows us to qua
 ntify the accuracy of image processing pipelines in recovering the rea
 l properties of targets in a survey. Given the high level of precision
  that current and future large-scale structure surveys are expected to
  achieve in constraining cosmological parameters\, a robust characteri
 zation of uncertainties is necessary\, in which SSI plays a critical r
 ole. Furthermore\, SSI is helpful in simulating weak-lensing magnifica
 tion effects\, as well as in providing a way to infer the photometric 
 redshifts of wide-field objects by extrapolating a color-redshift rela
 tionship from injected deep-field objects. The quantities derived from
  these applications are paramount to the cosmological analysis\, makin
 g SSI an important part of the process. In this talk\, I will describe
  Balrog\, the SSI effort in the Dark Energy Survey (DES) Y6 cosmologic
 al analysis\, in which we injected real sources from the deep fields o
 ver the entire 5000 deg^2 wide-field survey footprint. I will explain 
 the process of injecting the sources and validating the injected sampl
 e\, as well as the applications in the DES Y6 weak-lensing magnificati
 on and photometric redshift calibration projects. Finally\, I will hig
 hlight ongoing work on SSI for the Legacy Survey of Space and Time (LS
 ST)\, particularly on the recently released Data Preview 1 (DP1)\, as 
 well as future potential applications.
URL:https://www.physics.wisc.edu/events/?id=9341
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