DOI: 10.5281/zenodo.8423265
title: The NANOGrav 15-Year Data Set

description: <pre><strong>The NANOGrav 15-Year Data Set Public release "v2" 2023/10/09</strong> <strong>OVERVIEW</strong> -------- This file contains "narrowband" and "wideband" TOAs and timing solutions for the NANOGrav 15-year data set, covering data taken from 2004 to mid-2020 using Arecibo, the Green Bank Telescope (GBT), and the Very Large Array (VLA) with ASP/GASP and PUPPI/GUPPI/YUPPI backend instrumentation. The observations, data reduction, and analysis procedures used to produce these data are described in detail in the accompanying paper, "The NANOGrav 15-year Data Set: Observations and Timing of 68 Millisecond Pulsars" (Agazie et al., 2023, ApJL 951 L9, DOI 10.3847/2041-8213/acda9a, arXiv:2306.16217). This release is available at Zenodo (DOI 10.5281/zenodo.8423265). All *.par and *.tim files are ASCII and are formatted for use with standard pulsar timing packages such as tempo2 and PINT, except for profile template files which are FITS format (narrowband) or python pickle files (wideband). Correlation matrix files are available in three formats (*.txt, *.npz, and *.hdf5). See "description.txt" in both the narrowband and wideband ./correlations subdirectories for more details about these files. Questions about the contents of this data set can be addressed to Joe Swiggum (swiggumj@gmail.com) or comments@nanograv.org. <strong>DIRECTORY AND FILE STRUCTURE (FURTHER DETAILS BELOW)</strong> --------------------------------------------------- ./README This file. ./clock Files for tracing observatory-measured TOAs to clock standards. ./narrowband Directory containing the narrowband data set. Details are provided in README.narrowband in that directory. ./wideband Directory containing the wideband data set. Details are provided in README.wideband in that directory. ./correlations Directory containing the correlation matrix files for both the narrowband and wideband data. Details are provided in the /wideband/ and /narrowband/ subdirectories' description.txt files. <strong>SOFTWARE</strong> -------- This data set requires up-to-date installations of PINT or tempo2. Our original analysis used PINT v0.9.1 and tempo2 v2022.01.1. Up to date versions of these packages, as well as usage information and documentation can be found at the following repositories: PINT https://github.com/nanograv/PINT tempo2 https://bitbucket.org/psrsoft/tempo2 Note that we do not guarantee complete/correct functionality of these timing models in the older original tempo software package. Please also ensure that the clock files you are using cover the full range of the data set. Using the provided clock files (see below) will ensure this. All models included here are based on a generalized least squares (GLS) fit that includes a noise model with covariance between TOAs (ECORR/jitter parameters, if narrowband; RNAMP/RNIDX red noise parameters, if significant), as well as "traditional" EQUAD and EFAC parameters. Additional EFAC parameters for the wideband DM measurements are also included. All noise model parameters are included in the par files. <strong>CLOCK FILES</strong> ----------- The clock files used for our analysis are provided in the clock/ subdirectory. While the standard files distributed with tempo and tempo2 should be consistent with the clock files provided in the current release at the time of writing, this may be a source of inconsistent results in the future. Please see ./clock/README.clock directory for installation instructions. <strong>PLANNED REVISIONS</strong> ----------------- The initial release of the data set contained all fundamental data products needed for pulsar timing analysis: Times of arrival (.tim files), timing models (.par files), standard template profiles, clock correction files, and noise modeling MCMC chains. In v2, parameter correlation matrices were added, as well as alternate versions of timing model parameter files ("NoRedNoise" and "predictive"). A future release will add a number of other useful derived products as mentioned in the paper, including post-fit timing residuals and dispersion measure time series. <strong>CHANGE LOG</strong> ---------- 2023/09/19 Addition of "NoRedNoise" and "predictive" par files, correlation matrices, noise modeling chains (v2). 2023/07/01 Correction to tar.gz directory structure (v1.0.1). 2023/06/28 Initial public release (v1).</pre>
description: For a full author list, see: Gabriella Agazie et al 2023 ApJL 951 L9.
description: {"references": ["Gabriella Agazie et al 2023 ApJL 951 L9"]}