OSU College of Arts and Sciences Department of Astronomy

modsIDL
MODS Spectral Data Reduction Pipeline


Version 1.0 [2019 Feb 20]

Contents:

This is the first binocular release of the modsIDL package to the LBT partner community. This version includes the 2D transforms for reducing MODS2 grating mode data (MODS2 prism mode transforms are proving tricky and will be released next).

Dr. Kevin Croxall, the lead on the modsIDL project and its primary developer, left OSU (and Astronomy) in May 2016 and took a job with a Data Consulting company. Support for modsIDL will continue on an informal basis as we can find resources.

Please direct any bugs or questions to Rick Pogge (pogge.1@osu.edu), and we will try to address major issues promptly and post revisions on this webpage.

Note: this will be the last release using this website. Future versions will be released via GitHub.

Introduction

modsIDL is a suite of programs built on Jason Prochaska's XIDL package for the reduction of MODS long-slit and multi-slit spectroscopy. Long-slit spectra are considered to be a subset of multi-slit spectra. Both grating and prism mode spectra can be reduced using modsILD, but for the latter please contact us directly for advice, as prism mode is not as widely used and those parts of the pipeline are still in an advanced stage of development.

Sky subtraction, so critical for faint-object spectroscopy, is accomplished using the 2D B-Spline algorithm developed by Dan Kelson [2003, PASP, 115, 688]. The modsIDL pipeline maintains the original detector pixel grid throughout the steps leading up to 1D science spectrum extraction without geometric rectification. This allows us to robustly estimate and propagate errors throughout the reduction process, resulting in internally-consistent and robust 2D and 1D error arrays for each science target spectrum.

The ultimate output of modsIDL is a Multi-Extension FITS format file containing row-stacked 1D wavelength- and flux-calibrated sky-subtracted spectra with associated error arrays, sky spectra, and other related data.

Manual

Please download and read the
modsIDL Manual [4M PDF]
for instructions on how to use and install the modsIDL package. This manual describes essential details on how the programs work to take you from raw MODS CCD images to wavelength and flux calibrated sky-subtracted 1D spectra. and the 2D reduction steps required. Be sure to read it carefully before using these programs to process MODS raw images.

Terms & Conditions of Support

The modsIDL package is provided as-is, with no warranty or offer of individual user support. We are willing to fix bugs, answer basic questions, and provide updates (especially with MODS2 coming online), but individual instruction or hand-holding is beyond our limited human resources to provide.

We expect that users have a basic working knowledge of IDL at the level of knowing the basic command syntax and workflow of IDL pre-written procedures (a knowledge of IDL programming is helpful but not required for basic use). Similarly, we expect that users are well-acquainted with the basic principles of CCD spectroscopy in general and MODS spectra in particular.

Acknowledging modsIDL

modsIDL was developed for reducing data obtained with the MODS1 and MODS2 instruments at the Large Binocular Telescope Observatory. The MODS were built with with major support provided by grants from the U.S. National Science Foundation's Division of Astronomical Sciences Advanced Technologies and Instrumentation (AST-9987045), the NSF/NOAO TSIP Program, and matching funds provided by the Ohio State University Office of Research and the Ohio Board of Regents. Additional support was provided by NSF Grant AST-1108693.

If you used modsIDL in your research work, we ask that you follow emerging software citation principles being adopted by the astronomical community to ensure the proper citation of software in scientific publications.

The modsIDL pipeline was developed independently of the MODS instrument project as part of NSF Grant AST-1108693 which supported the Chemical Abundances of Spirals (CHAOS) project (PIs: Evan Skillman, UM, and Rick Pogge, OSU). It grew out of the need of the CHAOS project for an automated multi-object reduction and analysis pipeline for MODS data, and was intended from the start to be made available to the rest of the LBTO community as one of the "deliverables" of this NSF project. The modsIDL development project was led by Dr. Kevin Croxall, an OSU postdoc from 2012 until 2016.

If you publish MODS data reduced with the modsIDL pipeline, we ask that you add this line to the acknowledgments section of your paper: 

  This paper made use of the modsIDL spectral data reduction reduction 
  pipeline developed in part with funds provided by NSF Grant AST-1108693
  and a generous gift from OSU Astronomy alumnus David G. Price through 
  the Price Fellowship in Astronomical Instrumentation.
A software DOI has been registered with zenodo.org:
DOI
Follow this link to obtain a preformatted BibTeX entry you can use in your papers so that citations of this software will be tracked by ADS.

We and our funding agencies thank you for properly acknowledging their support in your papers.

Downloads

Current Version: v1.0 - 2019 Feb 20

Which version do I use?

"Just MODS" v1.0 Update
"Just MODS" v1.0 Update [288kb compressed tar]
"Just MODS" Update Instructions
GitHub Repository

Full xidl+modsIDL (first-time install or full re-install)
Linux Version 1.0 [245Mb compressed tar]
Mac OSX Version 1.0 [263Mb compressed tar]
Full xidl+modsIDL Installation Instructions

Notes
README file
Release Notes

System Requirements:

Example Data:
If you are running the worked example in chapter 5 of the manual, this is where you download the raw and processed data files:
modsIDL Example Data
Please read this page before downloading these files, as many of the packages are quite large (few Gb) and you need to know what you need before committing.
Updated: 2019 Feb 20 [rwp/osu]