Title:	The indian pulsar timing array data release 2: II. Customised single-pulsar noise analysis and noise budget
Authors:	Nobleson, K Dwivedi, Churchil Desai, Shantanu Joshi, Bhal Chandra Grover, Himanshu Deb, Debabrata Vyasraj, Vaishnavi Vara, Kunjal Tahbildat, Hemanga Susobhanah, Abhimanyu Surnis, Mayuresh Srivastava, Aman Sardana, Shubhit Takahashi, Keitaro Amarnath Arumugam, P Bagchi, Manjari Batra, Neelam Dhanda Chakraborty, Manoneeta Chowdhury, Shaswata Jacob, Shebin Jose Jose, Jibin Kala, Shubham Kato, Ryo Krishnakumar, M A Meena, Kuldeep Paladi, Avinash Kumar Pandian, Arul Rai, Kaustubh Rana, Prerna Singh, Manpreet Singha, Jaikhomba Shukla, Adya Tarafdar, Pratik Thiagraj, Prabu Zuraiq, Zenia
Keywords:	Pulsars Neutron stars Gravitational waves Pulsar timing arrays
Issue Date:	Jul-2026
Publisher:	Journal of High Energy Astrophysics
Citation:	Journal of High Energy Astrophysics, Vol. 53 (7), AR No. 100594
Abstract:	We present the results of customised single-pulsar noise analysis of 27 millisecond pulsars from the second data release of the Indian Pulsar Timing Array (InPTA-DR2). We model various stochastic noise sources present in the dataset using stationary Gaussian processes and estimate the noise budget of the InPTA-DR2 using Bayesian inference, involving model selection, Fourier harmonics selection, and parameter estimation for each pulsar. We check the efficacy of our noise characterisation by performing the Anderson-Darling test for Gaussianity on the noise-subtracted residuals. We find that all 11 pulsars with time baseline  ≲ 2.5 yr show Gaussian residuals and do not have evidence for any red noise process in the optimal model, except for PSR J1944 + 0907, which shows presence of DM noise. PSRs J0437 - 4715, J1909 - 3744 and J1939 + 2134 show preference for the most complicated noise model, having achromatic and chromatic red noise processes. Only 4 out of 15 pulsars with time baseline  ≳ 2.5 yr show significant non-Gaussianity in noise-subtracted residuals. We suspect that this may require more advanced methods to model noise processes properly. A comparative study of six pulsars with data removed near solar conjunctions showed deviations from the parameter estimates obtained with the original dataset, indicating potential bias in red noise processes due to unmodeled solar-wind effects. The results presented in this work remain broadly consistent with the InPTA-DR1 noise budget, with better constraints obtained on noise processes for several pulsars and support for achromatic red noise in PSR J1012 + 5307 due to the extended time baseline.
Description:	Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)
URI:	http://hdl.handle.net/2289/8704
ISSN:	2214-4056
Alternative Location:	https://doi.org/10.48550/arXiv.2512.20455 https://doi.org/10.1016/j.jheap.2026.100594
Copyright:	© 2026 Published by Elsevier B.V.
Appears in Collections:	Research Papers (A&A)

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