The NANOGrav nine-year data set: Noise budget for pulsar arrival times on intraday timescales

The use of pulsars as astrophysical clocks for gravitational wave (GW) experiments demands the highest possible timing precision. Pulse times of arrival (TOAs) are limited by stochastic processes that occur in the pulsar itself, along the line of sight through the interstellar medium, and in the measurement process. On timescales of seconds to hours, the TOA variance exceeds that from template-fitting errors due to additive noise. We assess contributions to the total variance from two additional effects: amplitude and phase jitter intrinsic to single pulses and changes in the interstellar impulse response from scattering. The three effects have different dependencies on time, frequency, and pulse signal-to-noise ratio. We use data on 37 pulsars from the North American Nanohertz Observatory for GWs to assess the individual contributions to the overall intraday noise budget for each pulsar. We detect jitter in 22 pulsars and estimate the average value of rms jitter in our pulsars to be similar to 1% of pulse phase. We examine how jitter evolves as a function of frequency and find evidence for evolution. Finally, we compare our measurements with previous noise parameter estimates and discuss methods to improve GW detection pipelines.

Title	The NANOGrav nine-year data set: Noise budget for pulsar arrival times on intraday timescales
Creator	Levin, L.
	Fonseca, E. F.
	Demorest, P. B.
	Zhu, W. W.
	Siemens, X.
	McLaughlin, M. A.
	Ferdman, R. D.
	Arzoumanian, Z.
	Stovall, K.
	Swiggum, J. K.
	Crowter, K.
	Jones, G.
	Chatterjee, S.
	Dolch, T.
	Pennucci, T. T.
	Ransom, S. M.
	Ellis, J. A.
	Jones, M. L.
	Nice, David J.
	Lam, M. T.
	Cordes, J. M.
	Gonzalez, M. E.
	Madison, D. R.
Publisher	Astrophysical Journal
Academic Department	Physics
Division	Natural Sciences
Organization	Lafayette College
Date Issued	March 10, 2016
Date Available	2016-04-08T19:53:42Z
Type	Article
Language	English
Keyword	pulsars: general
Keyword	gravitational waves
Bibliographic Citation	Lam, M. T., et al. (2016 Mar 10) "The NANOGrav nine-year data set: noise budget for pulsar arrival times on intraday timescales." Astrophysical Journal 89 (2): Article 155.
Standard Identifier	Handle 10385/2107
Standard Identifier	DOI 10.3847/0004-637X/819/2/155
Permalink	http://hdl.handle.net/10385/2107
Rights Statement	In Copyright
Rights Holders	The American Astronomical Society