Updating the Sensitivity Curves of the STIS Echelles (Post-SM4)

TL;DR

This paper updates the sensitivity curves for the STIS echelle modes post-SM4 using improved flux models and standard star observations, providing more accurate calibration data for astronomical measurements.

Contribution

The paper introduces revised on-orbit sensitivity curves for STIS echelle modes based on CALSPECv11 models, along with new calibration tables and procedures.

Findings

Updated sensitivity curves with 1-3% flux accuracy improvements

New blaze shift coefficients and echelle ripple tables released

Enhanced calibration procedures for post-SM4 observations

Abstract

The STIS team re-derived on-orbit sensitivity curves for the echelle modes for post-servicing mission 4 observations using the standard DA white dwarf G 191-B2B. These new updates relied on the recent CALSPECv11 models, which introduced improvements in the fluxes of the primary standard stars of the order of~1-3% depending on the wavelength of interest. As part of this effort, the team also released new blaze shift coefficients and echelle ripple tables. We present a detailed description of the procedures followed in the derivation of these new throughputs and the accompanying updates.