High Precision Measurements of Interstellar Dispersion Measure with the upgraded GMRT

Abstract

Pulsar radio emission undergoes dispersion due to the presence of free electrons in the interstellar medium (ISM). The dispersive delay in the arrival time of pulsar signal changes over time due to the varying ISM electron column density along the line of sight. Correcting for this delay accurately is crucial for the detection of nanohertz gravitational waves using Pulsar Timing Arrays. In this work, we present in-band and inter-band DM estimates of four pulsars observed with uGMRT over the timescale of a year using two different template alignment methods. The DMs obtained using both these methods show only subtle differences for PSR 1713+0747 and J1909$-$3744. A considerable offset is seen in the DM of PSR J1939+2134 and J2145$-$0750 between the two methods. This could be due to the presence of scattering in the former and profile evolution in the latter. We find that both methods are useful but could have a systematic offset between the DMs obtained. Irrespective of the template alignment methods followed, the precision on the DMs obtained is about $10^{-3}$ pc cm${}^{-3}$ using only BAND3 and $10^{-4}$ pc cm${}^{-3}$ after combining data from BAND3 and BAND5 of the uGMRT. In a particular result, we have detected a DM excess of about $5\times 10^{-3}$ pc cm${}^{-3}$ on 24 February 2019 for PSR J2145$-$0750. This excess appears to be due to the interaction region created by fast solar wind from a coronal hole and a coronal mass ejection (CME) observed from the Sun on that epoch. A detailed analysis of this interesting event is presented.

arXiv comment11 pages, 6 figures, 2 tables. Accepted by A&A

References in corpus (32)

• TEMPO2, a new pulsar timing package. I: Overview
• PSRCHIVE and PSRFITS An Open Approach to Radio Pulsar Data Storage and Analysis
• The NANOGrav 12.5-year Data Set: Search For An Isotropic Stochastic Gravitational-Wave Background
• Tempo2, a new pulsar timing package. II: The timing model and precision estimates
• DSPSR: Digital Signal Processing Software for Pulsar Astronomy
• High-precision timing of 42 millisecond pulsars with the European Pulsar Timing Array
• The International Pulsar Timing Array: First Data Release
• The North American Nanohertz Observatory for Gravitational Waves
• Limits on the Stochastic Gravitational Wave Background from the North American Nanohertz Observatory for Gravitational Waves
• The International Pulsar Timing Array: Second data release
• The Astrophysics of Nanohertz Gravitational Waves
• Measurement and correction of variations in interstellar dispersion in high-precision pulsar timing
• The Parkes Pulsar Timing Array
• Neutron Star Population Dynamics.I: Millisecond Pulsars
• The Parkes Pulsar Timing Array Project: Second data release
• Frequency-Dependent Dispersion Measures and Implications for Pulsar Timing
• The NANOGrav 12.5-year Data Set: Wideband Timing of 47 Millisecond Pulsars
• A pulsar-based timescale from the International Pulsar Timing Array
• Measuring pulse times of arrival from broadband pulsar observations
• The NANOGrav Nine-year Data Set: Monitoring Interstellar Scattering Delays
• An improved solar wind electron-density model for pulsar timing
• The impact of Solar wind variability on pulsar timing
• First detection of frequency-dependent, time-variable dispersion measures
• Dispersion measure variability for 36 millisecond pulsars at 150MHz with LOFAR
• On the usefulness of existing Solar-wind models for pulsar timing corrections
• Fourier domain excision of periodic radio frequency interference
• The NANOGrav 11-year Data Set: Solar Wind Sounding Through Pulsar Timing
• Tracking pulsar dispersion measures using the GMRT
• A Real-time Coherent Dedispersion Pipeline for the Giant Metrewave Radio Telescope
• pinta: The uGMRT Data Processing Pipeline for the Indian Pulsar Timing Array
• The effect of Pulse profile evolution on Pulsar Dispersion Measure
• A high time resolution study of the millisecond pulsar J2241-5236 at frequencies below 300 MHz

Cited by in corpus (18)

• The Indian Pulsar Timing Array: First data release
• Nanohertz Gravitational Wave Astronomy during the SKA Era: An InPTA perspective
• Status Report on Global Pulsar-Timing-Array Efforts to Detect Gravitational Waves
• Low-frequency wideband timing of InPTA pulsars observed with the uGMRT
• Noise analysis of the Indian Pulsar Timing Array data release I
• Pulsar Observations at Low Frequencies: Applications to Pulsar Timing and Solar Wind Models
• Validation of heliospheric modeling algorithms through pulsar observations I: Interplanetary scintillation-based tomography
• Do Pulsar and Fast Radio Burst dispersion measures obey Benford's law?
• The Indian Pulsar Timing Array Data Release 2: I. Dataset and Timing Analysis
• Bayesian pulsar timing and noise analysis with Vela.jl: an overview
• Multi-band Extension of the Wideband Timing Technique
• Wide-band timing of GMRT discovered millisecond pulsars
• Constraining CPT-odd electromagnetic chiral parameters with pulsar timing
• Effects of Coronal Mass Ejection on PSR J1022+1001 and Possible Mode Change of PSR J2145-0750 in the InPTA DR2
• Hypothesis of a bi-isotropic-like plasma permeating the interstellar space
• Improving DM estimates using low-frequency scattering-broadening estimates
• The Indian Pulsar Timing Array Data Release 2: II. Customised Single-Pulsar Noise Analysis and Noise Budget
• Classification of Pulsars using Extreme Deconvolution