Search

The wideband timing technique enables the high-precision simultaneous estimation of pulsar times of arrival (ToAs) and dispersion measures (DMs) while effectively modelling frequency-dependent profile evolution. We present two novel independent methods that extend the standard wideband technique to handle simultaneous multiband pulsar data incorporating profile evolution over a larger frequency span to estimate DMs and ToAs with enhanced precision. We implement the wideband likelihood using the libstempo python interface to perform wideband timing in the tempo2 framework. We present the application of these techniques to the data set of 14 millisecond pulsars (MSPs) observed simultaneously in Band 3 (300–500 MHz) and Band 5 (1260–1460 MHz) of the upgraded Giant Metrewave Radio Telescope (uGMRT) with a large band gap of 760 MHz as a part of the Indian Pulsar Timing Array (InPTA) campaign. We achieve increased ToA and DM precision and sub-microsecond root mean square post-fit timing residuals by combining simultaneous multiband pulsar observations done in non-contiguous bands for the first time using our novel techniques. [ABSTRACT FROM AUTHOR]

Glitches are the observational manifestations of superfluidity inside neutron stars. The aim of this paper is to describe an automated glitch detection pipeline, which can alert the observers on possible real-time detection of rotational glitches in pulsars. Post alert, the pulsars can be monitored at a higher cadence to measure the post-glitch recovery phase. Two algorithms, namely median absolute deviation and polynomial regression, have been explored to detect glitches in real time. The pipeline has been optimized with the help of simulated timing residuals for both the algorithms. Based on the simulations, we conclude that the polynomial regression algorithm is significantly more effective for real time glitch detection. The pipeline has been tested on a few published glitches. This pipeline is presently implemented at the Ooty Radio Telescope. In the era of upcoming large telescopes like SKA, several hundreds of pulsars will be observed regularly and such a tool will be useful for both real-time detection as well as optimal utilization of observation time for such glitching pulsars. [ABSTRACT FROM AUTHOR]

The abrupt change in the pulse period of a pulsar is called a pulsar glitch. In this paper, we present 11 pulsar glitches detected using the Ooty Radio Telescope (ORT) and the upgraded Giant Metrewave Radio Telescope (uGMRT) in high cadence timing observations of 8 pulsars. The measured relative amplitude of glitches (Δ ν / ν) from our data ranges from 10−6 to 10−9. Among these glitches, three are new discoveries, being reported for the first time. We also reanalyse the largest pulsar glitch in the Crab pulsar (PSR J0534+2200) by fitting the ORT data to a new phenomenological model including the slow rise in the post-glitch evolution. We measure an exponential recovery of 30 d after the Vela glitch detected on MJD 57734 with a healing factor Q  = 5.8 × 10−3. Further, we report the largest glitch (Δ ν / ν  = 3147.9 × 10−9) so far in PSR J1731−4744. [ABSTRACT FROM AUTHOR]

Although originally discovered as a radio-quiet gamma-ray pulsar, J1732-3131 has exhibited intriguing detections at decameter wavelengths. We report an extensive follow-up of the pulsar at 327 MHz with the Ooty radio telescope. Using the previously observed radio characteristics, and with an effective integration time of 60 h, we present a detection of the pulsar at a confidence level of 99.82 per cent. The 327 MHz mean flux density is estimated to be 0.5-0.8 mJy, which establishes the pulsar to be a steep spectrum source and one of the least luminous pulsars known to date. We also phase-aligned the radio and gamma-ray profiles of the pulsar, and measured the phase-offset between the main peaks in the two profiles to be 0.24 ± 0.06. We discuss the observed phase-offset in the context of various trends exhibited by the radio-loud gamma-ray pulsar population, and suggest that the gamma-ray emission from J1732-3131 is best explained by outer magnetosphere models. Details of our analysis leading to the pulsar detection, and measurements of various parameters and their implications relevant to the pulsar's emission mechanism are presented. [ABSTRACT FROM AUTHOR]