Photometry

We are creating a pipeline that will construct a time-varying model of the scene by using all available images of that region. The goal for this pipeline is to optimize imaging for detection which is set by the photometric accuracy and precision requirements of the cosmological analysis. We want to make this pipeline for general use in discovering transients, validate the pipeline with <2 mmag bias, and measure host galaxy photometry and physical properties.

• Build a general-use pipeline for rapid transient discovery

  • This pipeline will be built to discover transients with high efficiency and photometric accuracy of >30 mmag.

  • This pipeline will also act quickly in discovery as it will identify transients within an hour of the SOC-calibrated images becoming available.

  • Alongside the pipeline, we will also be developing tools for image subtraction as well as infrastructure that is specific to Roman that will robustly exploit available information of Roman images.

• Develop a scene-modeling pipeline with <2 mmag bias

  • This pipeline will be developed to extract accurate photometric light curves by use of the scene-modeling approach.

  • This method will make use our previous calibrations, accurate measurements for position, time, flux, and color-dependent PSF models.

  • Biases for this will be required to be smaller than the calibration accuracy which is 2 mmag.

• Measure host galaxies photometry and physical properties

  • This pipeline will produce deep SN-free co-adds, perform model-fitting photometry, and derive physical properties of galaxies that can be used to analyze rates and correlations between transient and host galaxy properties.