ACS STAN April 2023

1. New ACS Observing Mode — Imaging Spectropolarimetry

D. Hines, N. Hathi, Y. Cohen, N. Grogin, and M. Chiaberge

We encourage HST Cycle 31 proposers to consider the newly available ACS imaging spectropolarimetry mode. The ACS polarizers (POL0V; POL60V; POL120V) can be used in conjunction with the G800L grism to provide low spectral resolving power (R~100 @ 8000Å) imaging spectropolarimetry from ~5500Å – 8000Å. This observing mode is still being calibrated during Cycle 30. Therefore, prior to proposing, potential observers should contact the Help Desk to discuss their specific goals and the current status of the mode. More details are discussed in ACS Instrument Handbook Section 6.1.4 and ACS Data Handbook Section 5.3.5.

2. HSTaXe Version 1.0.3 Released

N. Hathi, R. Avila, R. O'Steen, D. Nguyen, D. Som, A. Pidgeon, and B. Kuhn

We announce the release of HSTaXe v.1.0.3 featuring several improvements. HSTaXe is the official STScI-provided software package for the extraction and calibration of slitless spectroscopic data from the HST and replaces the IRAF/PyRAF-based aXe software (no longer supported). The major improvements provided by HSTaXe v1.0.3 are:

• Streamlined installation process

• Improved documentation, including the creation of a new documentation page

Please visit the HSTaXe GitHub repository and the documentation page for instructions on installing and using the software.

In addition, the ACS team announces the availability of two new Jupyter notebooks demonstrating example extraction workflows for ACS slitless spectroscopic data. These notebooks are located in the HSTaXe repository.