| Author(s) and Co-Author(s) with Affiliation: K. Nobleson(Faculty of Advanced Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto City, 860-8555, Kumamoto, Japan), Churchil Dwivedi(Astronomy and Astrophysics Division, Physical Research Laboratory, Thaltej Campus, Thaltej, Ahmedabad, 380059, Gujarat, India), Shantanu Desai(Department of Physics, IIT Hyderabad, Kandi, 502284, Telangana, India), Bhal Chandra Joshi(1) National Centre for Radio Astrophysics, SP Pune University Campus, Pune, 411007, Maharashtra, India), Himanshu Grover(Department of Physics, Indian Institute of Technology Roorkee, Roorkee, 247667, Uttarakhand, India), Debabrata Deb(Centre for Space Research, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa), Vaishnavi Vyasraj(Department of Physics, IIT Hyderabad, Kandi, 502284, Telangana, India), Kunjal Vara(Department of Physics, Indian Institute of Science Education and Research, Bhauri Bypass Road, Bhopal, 462066, Madhya Pradesh,IN), Hemanga Tahbildar(Department of Physics, Indian Institute of Science Education and Research, Bhauri Bypass Road, Bhopal, 462066, Madhya Pradesh,IN), Abhimanyu Susobhanan(School of Physics, IISER Thiruvananthapuram, Maruthamala PO, Thiruvananthapuram, 695551, Kerala, India), Mayuresh Surnis(Department of Physics, Indian Institute of Science Education and Research, Bhauri Bypass Road, Bhopal, 462066, Madhya Pradesh,IN), Aman Srivastava(Department of Physics, IIT Hyderabad, Kandi, 502284, Telangana, India) |
| Abstract: The Indian Pulsar Timing Array (InPTA) exploits the unique capabilities of the upgraded Giant Metrewave Radio Telescope (uGMRT) to observe millisecond pulsars (MSPs) simultaneously in the 300-500 MHz and 1260-1460 MHz bands. In this work, we present results from a customized single-pulsar noise analysis of 27 MSPs from the second InPTA data release (InPTA-DR2). Stochastic red noise processes are modelled using stationary Gaussian processes, and Bayesian inference is employed for model selection, Fourier harmonic selection, and parameter estimation. The reliability of the noise modelling is assessed using the Anderson-Darling test applied to noise-subtracted timing residuals.
We find that all 11 pulsars with time baselines ≲2.5 yr exhibit Gaussian residuals and show no evidence for red noise, with the exception of PSR J1944+0907, which displays dispersion-measure (DM) noise. PSRs J0437−4715, J1909−3744, and J1939+2134 favour more complex noise models incorporating both achromatic and chromatic red noise components. Among pulsars with baselines ≳2.5 yr, only four show significant non-Gaussianity. 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.. Overall, our results are consistent with those from InPTA-DR1, with improved constraints on noise properties and additional support for achromatic red noise in PSR J1012+5307 enabled by the extended dataset. |
