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Lookup NU author(s): Dr Anne ArchibaldORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2024. The Author(s). Published by the American Astronomical Society.Pulsar timing arrays (PTAs) are designed to detect low-frequency gravitational waves (GWs). GWs induce achromatic signals in PTA data, meaning that the timing delays do not depend on radio frequency. However, pulse arrival times are also affected by radio-frequency-dependent “chromatic” noise from sources such as dispersion measure (DM) and scattering delay variations. Furthermore, the characterization of GW signals may be influenced by the choice of chromatic noise model for each pulsar. To better understand this effect, we assess if and how different chromatic noise models affect the achromatic noise properties in each pulsar. The models we compare include existing DM models used by the North American Nanohertz Observatory for Gravitational waves (NANOGrav) and noise models used for the European PTA Data Release 2 (EPTA DR2). We perform this comparison using a subsample of six pulsars from the NANOGrav 15 yr data set, selecting the same six pulsars as from the EPTA DR2 six-pulsar data set. We find that the choice of chromatic noise model noticeably affects the achromatic noise properties of several pulsars. This is most dramatic for PSR J1713+0747, where the amplitude of its achromatic red noise lowers from log 10 A RN = − 14.1 − 0.1 + 0.1 to − 14.7 − 0.5 + 0.3 , and the spectral index broadens from γ RN = 2.6 − 0.4 + 0.5 to γ RN = 3.5 − 0.9 + 1.2 . We also compare each pulsar's noise properties with those inferred from the EPTA DR2, using the same models. From the discrepancies, we identify potential areas where the noise models could be improved. These results highlight the potential for custom chromatic noise models to improve PTA sensitivity to GWs.
Author(s): Larsen B, Mingarelli CMF, Hazboun JS, Chalumeau A, Good DC, Simon J, Agazie G, Anumarlapudi A, Archibald AM, Arzoumanian Z, Baker PT, Brook PR, Cromartie HT, Crowter K, DeCesar ME, Demorest PB, Dolch T, Ferrara EC, Fiore W, Fonseca E, Freedman GE, Garver-Daniels N, Gentile PA, Glaser J, Jennings RJ, Jones ML, Kaplan DL, Kerr M, Lam MT, Lorimer DR, Luo J, Lynch RS, McEwen A, McLaughlin MA, McMann N, Meyers BW, Ng C, Nice DJ, Pennucci TT, Perera BBP, Pol NS, Radovan HA, Ransom SM, Ray PS, Schmiedekamp A, Schmiedekamp C, Shapiro-Albert BJ, Stairs IH, Stovall K, Susobhanan A, Swiggum JK, Wahl HM, Champion DJ, Cognard I, Guillemot L, Hu H, Keith MJ, Liu K, McKee JW, Parthasarathy A, Perrodin D, Possenti A, Shaifullah GM, Theureau G
Publication type: Article
Publication status: Published
Journal: Astrophysical Journal
Year: 2024
Volume: 972
Issue: 1
Print publication date: 01/09/2024
Online publication date: 23/08/2024
Acceptance date: 29/05/2024
Date deposited: 03/09/2024
ISSN (print): 0004-637X
ISSN (electronic): 1538-4357
Publisher: Institute of Physics
URL: https://doi.org/10.3847/1538-4357/ad5291
DOI: 10.3847/1538-4357/ad5291
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