A.1 Introduction

This appendix, organized by channel and filter, contains the system throughputs and sensitivities of each filter. For each imaging mode the following are provided:

  • Plots of integrated system throughput for each filter as a function of wavelength.
  • Plots of the time needed to achieve a desired signal-to-noise ratio vs. magnitude for each filter for a point-source and for a 1"× 1" extended source.
  • Tables of color corrections ABν to go from Johnson V magnitude to AB magnitude for stellar spectra (as a function of effective temperature) and composite populations (as a function of age). The stellar spectra come from the Lejeune et al. (1997, A&AS125, 229) grid, and assume a surface gravity of log g = 5 and solar metallicity. The composite populations come from the "instantaneous burst" and "continuous star formation" models of Bruzual & Charlot (1993, ApJ405, 539), updated in 1995, assuming a Salpeter IMF spanning 0.1 to 125 solar masses.

The filter throughput values presented here were derived with stsynphot by using the latest WFC3 photometric calibration released on October 2020 for both the UVIS (WFC3 ISR 2020-10) and the IR (WFC3 ISR 2021-04) detectors. The throughput values for WFC3/UVIS are calculated at a reference time, June 26, 2009, i.e. approximately when WFC3 was installed on HST. For more information on the latest calibration please see the photometric calibration webpage

To derive photometric transformation coefficients for converting magnitudes from the native WFC3/UVIS passbands to Johnson/Cousins UBVRI passbands in the ABMAG, STMAG, and VEGAMAG systems, a Jupyter notebook is provided. This notebook uses the latest WFC3 filter throughput tables and replaces the functionality provided in the "WFC3 Photometric Conversion Tool", which is no longer supported. For more details on photometric transformations to other systems, please see WFC3 ISR 2014-16.


For more information on system throughputs and tabular files to download, see the HST System Throughputs website.