SUPERBACK: Building an Empirically Motivated Background Model to Optimize Roman Observations
PI: Carleton, Timothy, Arizona State University
Wide-Field Science – Regular
The majority of photons detected with Roman’s WFI will come from large-scale diffuse foregrounds within our Solar System and Galaxy. Accurate accounting for these foregrounds is critical to analyze the distant galaxies that are the focus of Roman’s High-Latitude Wide Area and Time-Domain Surveys, as well as any extragalactic General Astrophysics program. However, software to deal with these image backgrounds is missing from the Roman ecosystem. SUPERBACK outlines a proposal to (1) improve forecasting of the backgrounds expected in Roman WFI images and (2) develop a pipeline to model all large-scale backgrounds in Roman WFI images.
In addition to enhancing the science of Roman extragalactic observations by improving data quality, this pipeline will enable a wide range of science focused on those backgrounds, ranging from cosmology to Solar System science, such as:
• Roman will be capable of precise measurements of the level and power spectrum of the diffuse cosmic optical and near-IR background. Ensuring that diffuse foregrounds are accurately accounted for will ensure that this science is possible.
• Diffuse Galactic Light represents a non-negligible component of the background in WFI images (even in relatively high-latitude regions). Modeling this component in WFI images will facilitate a better understanding of the diffuse dust and gas giving rise to this emission.
• Despite its nearby origin, models of Zodiacal Light are currently uncertain by ~5%. Examining the difference between the predictions of up-to-date Zodiacal Light models and observations of the overall background level in WFI images can provide useful constraints on the structure and scattering properties of dust in our Solar System.
It goes without saying that improving the background subtraction of WFI images will significantly enhance low surface brightness science beyond our Milky Way. Robust measurements of Intercluster and Intrahalo light, as well as Ultra Diffuse Galaxies, will certainly benefit from this proposal.
The SUPERBACK background model will include 4 position and time-dependent components: Zodiacal Light, Diffuse Galactic Light, telescope thermal emission, and extended PSF structure. We will first improve predictions of the level of Zodiacal Light, Diffuse Galactic Light, and thermal emission included in Roman observation planning tools. Next, we will develop a pipeline to model all these components in WFI images. This pipeline will be released to the community in order to enable (a) science on these diffuse backgrounds and (b) improved image quality for general astrophysics.
The SUPERBACK project represents an important component of the Roman ecosystem, preparing astronomers to conduct a wide range of scientific exploration with this telescope.