Three-dimensional scene reconstruction using Roman slitless spectra

Published

January 14, 2026

Author(s)

Tri Astraatmadja, Andrew Fruchter, Susana Deustua, Helen Qu, Masao Sako

Abstract

The \Romanc} Space Telescope will carry out a wide-field imaging and slitless spectroscopic survey of TypeIa Supernovae to achieve one of its main goals, improving our understanding of dark energy. Crucial to this endeavor is obtaining a spectra of the supernovae devoid of contamination by light from the underlying host galaxies. Obtaining such spectra is made even more difficult by an inherent problem in wide-field slitless spectroscopic surveys, the blending of spectra of close objects. The spectrum of a supernova will blend with that of its host galaxy, potentially even from regions that are tens of pixels distant from the supernova on the sky. If not properly removed, this contamination will introduce systematic bias when the supernova spectrum is later used to determine its luminosity distance and to infer the parameters of dark energy. To address this problem we developed an algorithm that makes use of the spectroscopic observations of the host galaxy at all available observatory roll angles to reconstruct a three-dimensional (2-d spatial, 1-d spectral) representation of the underlying host galaxy that accurately matches the 2-d slitless spectrum of the host galaxy when projected to an arbitrary rotation angle. This projection can be subtracted from an observation of a supernova to remove the contamination from the underlying host. Using simulated \Roman} data, we show that our method has extremely small systematic errors and significantly less random noise than if we subtracted a single perfectly aligned spectrum of the host obtained before or after the supernova was visible.

Citation

Astrophysical Journal

Pub Type

Journals

Keywords

supernova, Type Ia Supernova, Roman, spectroscopy, prism

Citation

Astraatmadja, T. , Fruchter, A. , Deustua, S. , Qu, H. and Sako, M. (2026), Three-dimensional scene reconstruction using Roman slitless spectra, Astrophysical Journal (Accessed January 16, 2026)