paper

Milky Way Tomography with the SkyMapper Southern Survey. II. Photometric Re-calibration of SMSS DR2

arXiv:2011.07172 · doi:10.3847/1538-4357/abca37

Abstract

We apply the spectroscopy-based stellar-color regression (SCR) method to perform an accurate photometric re-calibration of the second data release from the SkyMapper Southern Survey (SMSS DR2). From comparison with a sample of over 200,000 dwarf stars with stellar atmospheric parameters taken from GALAH+ DR3 and with accurate, homogeneous photometry from DR2, zero-point offsets are detected in the original photometric catalog of SMSS DR2, in particular for the gravity- and metallicity-sensitive bands. For bands, the zero-point offsets are close to zero at very low extinction, and then steadily increase with , reaching as large as 0.174 and 0.134 mag respectively, at mag. These offsets largely arise from the adopted dust term in the transformations used by SMSS DR2 to construct photometric calibrators from the ATLAS reference catalog. For the bands, the zero-point offsets exhibit negligible variations with SFD , due to their tiny coefficients on the dust term in the transformation. Our study also reveals small, but significant, spatial variations of the zero-point offsets in all bands. External checks using Strömgren photometry, WD loci and the SDSS Stripe 82 standard-star catalog independently confirm the zero-points found by our revised SCR method.

16 pages, 13 figures, 5 tables, accepted for publication in ApJ; we also provide the routines and scripts on GitHub (github.com/comhy/SMSS-DR2-ZP-corrections) for the corrections of the zero-points of SMSS DR2/3 photometry

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