Stellar color regression: a spectroscopy based method for color calibration to a few mmag accuracy and the recalibration of Stripe 82
arXiv:1412.1231 · doi:10.1088/0004-637X/799/2/133
Abstract
In this paper, we propose a spectroscopy based Stellar Color Regression (SCR) method to perform accurate color calibration for modern imaging surveys, taking advantage of millions of stellar spectra now available. The method is straightforward, insensitive to systematic errors in the spectroscopically determined stellar atmospheric parameters, applicable to regions that are effectively covered by spectroscopic surveys, and capable of delivering an accuracy of a few millimagnitudes for color calibration. As an illustration, we have applied the method to the SDSS Stripe 82 data (Ivezic et al; I07 hereafter). With a total number of 23,759 spectroscopically targeted stars, we have mapped out the small but strongly correlated color zero point errors present in the photometric catalog of Stripe 82, and improve the color calibration by a factor of 2 -- 3. Our study also reveals some small but significant magnitude dependence errors in z-band for some CCDs. Such errors are likely to be present in all the SDSS photometric data. Our results are compared with those from a completely independent test based on the intrinsic colors of red galaxies presented by I07. The comparison as well as other tests shows that the SCR method has achieved a color calibration internally consistent at a level of about 5 mmag in u-g, 3 mmag in g-r, and 2 mmag in r-i and i-z, respectively. Given the power of the SCR method, we discuss briefly the potential benefits by applying the method to existing, on-going, and up-coming imaging surveys.
17 pages, 14 figures, 3 tables, ApJ in press
References in corpus (8)
- The Milky Way Tomography with SDSS: II. Stellar Metallicity
- The SEGUE Stellar Parameter Pipeline. I. Description and Initial Validation Tests
- Stellar SEDs from 0.3-2.5 Microns: Tracing the Stellar Locus and Searching for Color Outliers in SDSS and 2MASS
- SDSS Standard Star Catalog for Stripe 82: the Dawn of Industrial 1% Optical Photometry
- The SEGUE Stellar Parameter Pipeline. II. Validation with Galactic Globular and Open Clusters
- Cosmological baryonic and matter densities from 600,000 SDSS Luminous Red Galaxies with photometric redshifts
- Toward 1% Photometry: End-to-end Calibration of Astronomical Telescopes and Detectors
- A three dimensional extinction map of the Galactic Anticentre from multi-band photometry