status DOI

IGRINS RV: A Radial Velocity Pipeline for IGRINS#

IGRINS RV is a python open source pipeline for extracting radial velocities (RVs) from spectra taken with the Immersion GRating INfrared Spectrometer (IGRINS). It uses a modified forward modeling technique that leverages telluric absorption lines as a common-path wavelength calibrator. IGRINS RV achieves an RV precision in the H and K bands of around 25-30 m/s for narrow-line stars, and it has successfully recovered the planet-induced RV signals of both HD 189733 and τ Boo A. Visit Stahl et al. 2021 to see the published paper.

If you have any questions, suggestions, or wish to report a bug, please let us know by either opening an issue or contacting us: Asa G. Stahl (asa.stahl@rice.edu) or Shih-Yun Tang (sytang@lowell.edu). More on how to contribute can be found in Q: How do I help make IGRINS RV better? page.

Starting from v1.5.1, the example data & synthetic stellar templates are not shipped with IGRINS RV as to reduce the repo size. Synthetic stellar templates are now stored on google drive link.

News:

  • 2022/10/12: IGRINS RV v1.5.1!!

    • Who might be effected?

      • People with only a few observations (<~5) that use K band.

      • People who need more precise ABSOLUTE RV.

    • What’s new?:

      1. Significantly reduced the K band RV shift between orders.

      2. Removed choice between relative and absolute RV modes (for both H and K band). Now only absolute RVs are calculated, but an order-to-order RV correction is still applied, and the uncertainties provided are updated to take into account this correction. (for more info, see What’s new in v1.5.1?)

      3. Dropped the usage of Order 3 for K band RV calculation, as well as Order 4 during the period when IGRINS was slightly defocused as the result of a mounting issue.

For the sake of efficiency, IGRINS RV is broken up into several different steps. After installed (see Installation) all the required packages, the best way to learn how these steps work is to follow our Demo with Example Data (GJ281) using the example data provided. The demo will demonstrate how one user might run the steps of IGRINS RV to go from raw data to final RV measurements.

Quick Start

As you go through the demo, navigate to the other document pages as they are linked to get a more detailed description of how each step works and why you’re running it. Once you’ve finished the demo and would like to begin analyzing your real science targets, these other pages will also explain what options you have for modifying the code’s default inputs to best suit the needs of your science:

Setup

Main RV program

Other

Please cite these papers if you use IGRINS RV: