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Abstract We calibrate spectrophotometric optical spectra of 32 stars commonly used as standard stars, referenced to 14 stars already on the Hubble Space Telescope–based CALSPEC flux system. Observations of CALSPEC and non-CALSPEC stars were obtained with the SuperNova Integral Field Spectrograph over the wavelength range 3300–9400 Å as calibration for the Nearby Supernova Factory cosmology experiment. In total, this analysis used 4289 standard-star spectra taken on photometric nights. As a modern cosmology analysis, all presubmission methodological decisions were made with the flux scale and external comparison results blinded. The large number of spectra per star allows us to treat the wavelength-by-wavelength calibration for all nights simultaneously with a Bayesian hierarchical model, thereby enabling a consistent treatment of the Type Ia supernova cosmology analysis and the calibration on which it critically relies. We determine the typical per-observation repeatability (median 14 mmag for exposures ≳5 s), the Maunakea atmospheric transmission distribution (median dispersion of 7 mmag with uncertainty 1 mmag), and the scatter internal to our CALSPEC reference stars (median of 8 mmag). We also check our standards against literature filter photometry, finding generally good agreement over the full 12 mag range. Overall, the mean of our system is calibrated to the mean of CALSPEC at the level of ∼3 mmag. With our large number of observations, careful cross-checks, and 14 reference stars, our results are the best calibration yet achieved with an integral-field spectrograph, and among the best calibrated surveys.
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This content will become publicly available on February 26, 2026
MOMOS: The Multi-Object MKID Optical Spectrometer Simulator and Data Reduction Package
Abstract The Multi-Object MKID Optical Spectrometer (MOMOS) is a proposed visible wavelength spectrograph that uses microwave kinetic inductance detectors (MKIDs) targeting an initial resolving power of 3500 for up to five fiber inputs. With their modest wavelength-resolving abilities, MKIDs take the place of both the cross disperser and detector in the spectrograph. MKIDs lack read noise and dark current enabling noiseless post-observation rebinning and characterization of faint objects, as well as time-resolved photon-counting spectroscopy. This work presents a MOMOS simulator customizable for different MOMOS configurations. Treating simulator products as inputs, an algorithm was developed and implemented in the MOMOS data reduction package to calibrate and extract spectra.
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- Award ID(s):
- 2304168
- PAR ID:
- 10590923
- Publisher / Repository:
- American Astronomical Society
- Date Published:
- Journal Name:
- The Astronomical Journal
- Volume:
- 169
- Issue:
- 3
- ISSN:
- 0004-6256
- Page Range / eLocation ID:
- 176
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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