The NANOGrav 15-Year Data Set

The NANOGrav 15-Year Data Set
Public release "v1.0.1" 2023/07/01

OVERVIEW
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  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.7967585).

  All 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).

  Questions about the contents of this data set can be addressed to Joe Swiggum (swiggumj@gmail.com) or comments@nanograv.org.

DIRECTORY AND FILE STRUCTURE (FURTHER DETAILS BELOW)
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    ./README
        Explanatory file and documentation.
    ./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.

SOFTWARE
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  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.

CLOCK FILES
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  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.

PLANNED REVISIONS
-----------------

  The initial release of the data set contains all fundamental data products needed for pulsar timing analysis:  Times of arrival (.tim files), timing models (.par files), standard template profiles, and clock correction files.  A future release will add a number of other useful derived products as mentioned in the paper, including post-fit timing residuals, dispersion measure time series, noise modeling MCMC chains, and parameter correlation matrices.

CHANGE LOG
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2023/07/01
    Correction to tar.gz directory structure (v1.0.1)

2023/06/28
    Initial public release (v1.0.0).