6 - DCR_CORRECTIONS: Wavelength-dependent Atmospheric Corrections

Overview

We release the photometric corrections due to wavelength-dependent atmospheric effects (DCR and wavelength-dependent seeing) applied to our SNe Ia (Lee & Acevedo et al. 2023).

For the SHAPE effect, the flux ratio values in the look-up tables can be translated to the SHAPE magnitude corrections. For the COORD effect, the user can start from the altitude shifts vs. g-i values of stars and calculate the COORD magnitude corrections. Please calculate the MAGCOR values following the tutorial and use them (not the table MAGCOR_COORD values) for the COORD magnitude corrections.

More details on the conversion from the relevant tables to the SHAPE and COORD magnitude corrections can be found in the DES SN 5YR Tutorial Part 5: Lambda Dependent corrections

Data Format

For COORD & SHAPE

  • Magnitude Corrections table: DCRADJ_MAGCOR_v220929.csv contains all the magnitude corrections (both COORD and SHAPE) to be added to the uncorrected (SALT2 or SALT3) magnitudes

  • CID - Candidate ID

  • EXPNUM - Exposure Number

  • MAG_MODEL_g - Model g band magnitude

  • MAG_MODEL_i - Model i band magnitude

  • AIRMASS - Air Mass

  • PSF_FWHM_ASEC - PSF FWHM in arcseconds

  • MAGCOR_COORD - Magnitude corrections (COORD) to be added to the uncorrected magnitudes

  • MAGCOR_SHAPE - Magnitude corrections (SHAPE) to be added to the uncorrected magnitudes

  • RADEG & DECDEG - Right Acension (RA) and Declination (DEC) of SN in the given exposure in degrees

  • BAND - Band (filter) of the observation

  • SNR - S/N of the SN

  • dRA & dDEC - DCR altitude shift converted to RA and DEC coordinates

  • ddRA & ddDEC - DCR altitude shift in RA and DEC with respect to the S/N weighted average coordinate

  • ADJOFF - Total offset with respect to the S/N weighted average coordinate

For COORD only

  • DCR Coordinate table: DCR_dictionary.csv contains the altitude shifts vs. g-i magnitude

  • SLOPE_ALT - slope of altitude Alt vs. g-i color

  • YINT_ALT - y-intercept of altitude Alt vs. g-i` color

  • mmag_vs_fracpsf_Moffat3.txt contains the magnitude offset by the astrometric offset in fractions of the PSF size for a Moffat PSF.

  • DCR_coord_table.csv contains the MAGCOR_DCR (COORD) by CID and exposure number but is not necessary for the calculations.

For SHAPE only

  • Wavelength-dependent corrections lookup table:

  • Flux ratio values for the g and r bands by g-i, Air Mass, and PSF FWHM.

  • flux_ratio_values_g_table_DCR_shape.npy

  • flux_ratio_values_r_table_DCR_shape.npy

  • g-i values, Air MAss, and PSF FWHM (in arcseconds).

  • g_table_DCR_shape_xyz_columns.npy

  • r_table_DCR_shape_xyz_columns.npy