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Abstract Differential Chromatic Refraction (DCR) is caused by the wavelength dependence of our atmosphere’s refractive index, which shifts the apparent positions of stars and galaxies and distorts their shapes depending on their spectral energy distributions. While this effect is typically mitigated and corrected for in imaging observations, we investigate how DCR can instead be used to our advantage to infer the redshifts of supernovae from multiband, time-series imaging data. We simulate Type Ia supernovae in the proposed Vera C. Rubin Observatory Legacy Survey of Space and Time Deep Drilling Field, and evaluate astrometric redshifts. We find that the redshift accuracy improves dramatically with the statistical quality of the astrometric measurements as well as with the accuracy of the astrometric solution. For a conservative choice of a 5 mas systematic uncertainty floor, we find that our redshift estimation is accurate atz< 0.6. We then combine our astrometric redshifts with both host-galaxy photometric redshifts and supernovae photometric (light-curve) redshifts and show that this considerably improves the overall redshift estimates. These astrometric redshifts will be valuable, especially since Rubin will discover a vast number of supernovae for which we will not be able to obtain spectroscopic redshifts.
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This content will become publicly available on November 12, 2026
Enhancing Multiplet Alignment Measurements with Imaging
Abstract We demonstrate that measurements of the gravitational tidal field made with spectroscopic redshifts can be improved with information from imaging surveys. The average orientation of small groups of galaxies, or “multiplets” is correlated with large-scale structure and is used to measure the direction of tidal forces. Previously, multiplet intrinsic alignment has been measured in DESI using galaxies that have spectroscopic redshifts. The DESI Legacy Imaging catalog can be used to supplement multiplet catalogs. Our findings show that galaxy positions from the imaging catalog produce a measurement similar to the measurements made with only spectroscopic data. This demonstrates that imaging can improve our signal-to-noise ratio for multiplet alignment in DESI.
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- Award ID(s):
- 2502789
- PAR ID:
- 10680715
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- Research Notes of the AAS
- Date Published:
- Journal Name:
- Research Notes of the AAS
- Volume:
- 9
- Issue:
- 11
- ISSN:
- 2515-5172
- Page Range / eLocation ID:
- 305
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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