THE NANOGRAV NINE-YEAR DATA SET: OBSERVATIONS, ARRIVAL TIME MEASUREMENTS, AND ANALYSIS OF 37 MILLISECOND PULSARS

By Z. Arzoumanian, A. Brazier, S. Burke-Spolaor, S. Chamberlin, S. Chatterjee, B. Christy, J. Cordes, N. Cornish, K. Crowter, P. Demorest and 34 more. 2015

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We present high-precision timing observations spanning up to nine years for 37 millisecond pulsars monitored with the Green Bank and Arecibo radio telescopes as part of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) project. We describe the observational and instrumental setups used to collect the data, and methodology applied for calculating pulse times of arrival; these include novel methods for measuring instrumental offsets and characterizing low signal-to-noise ratio timing results. The time of arrival data are fit to a physical timing model for each source, including terms that characterize time-variable dispersion measure and frequency-dependent pulse shape evolution. In conjunction with the timing model fit, we have performed a Bayesian analysis of a parameterized timing noise model for each source, and detect evidence for excess low-frequency, or “red,” timing noise in 10 of the pulsars. For 5 of these cases this is likely due to interstellar medium propagation effects rather than intrisic spin variations. Subsequent papers in this series will present further analysis of this data set aimed at detecting or limiting the presence of nanohertz-frequency gravitational wave signals.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/100943c4564065101fb2eb1229faf0016264f8d9

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Citations in the corpus

The NANOGrav 11 Year Data Set: Pulsar-timing Constraints on the Stochastic Gravitational-wave Background (2018, methodology): “The SSE model used for the original analysis of the 5-year dataset (Demorest et al. 2013) was DE405 (Standish 2004), while for the 9-year dataset (Arzoumanian et al. 2015) all data (whether new, or from the 5-year dataset) was modeled with DE421 (Folkner et al. 2009).”
Searching for isotropic stochastic gravitational-wave background in the international pulsar timing array second data release (2021, unknown): “The IPTA DR2 [ 31 ] was created by combining published data from individual PTA data releases, including EPTA DR1 [ 32 ] , NANOGrav 9 year data set [ 33 ] , and PPTA DR1 [ 18 ] .”
Approximate Universal Relations for Neutron Stars and Quark Stars (2016, background): “Observe how the mass-radius curve can be drastically different as one varies the equation of state, with most still passing the constraints imposed by the massive pulsars J1614-2230 [122, 138] (green dot-dashed horizontal line), J0348+0432 [123] (red dot-dashed horizontal line) and Vela X-1 [124–126”
The International Pulsar Timing Array: First Data Release (2016, methodology): “…different systems, at a level of precision beyond the presently achieved pulsar timing precision, are being developed (Manchester et al. 2013; Arzoumanian et al. 2015), but are as yet in their infancy and not widely adopted, or only applicable to data from multiple systems on a single…”
The NANOGrav 11-year Data Set: High-precision Timing of 45 Millisecond Pulsars (2017, methodology): “The timing and noise analysis methods used for the 11- year data set are nearly identical to those described in our previous (9-year) data set paper, Arzoumanian et al. (2015b).”