# The UTMOST pulsar timing programme I: overview and first results

## TL;DR

This paper reports on the first results of the UTMOST pulsar timing project, which improves pulsar parameter measurements, investigates their long-term spin-down and velocities, and introduces an efficient autonomous observing system.

## Contribution

It provides updated timing models for over 200 pulsars, enhances parameter precision, and introduces a dynamic scheduling system for improved observational efficiency.

## Key findings

- Improved parameter precision for 123 pulsars, with 47 by over an order of magnitude.
- Estimated proper motions for 60 pulsars, 24 of which are newly determined.
- A two-Gaussian model best fits the pulsar transverse velocity distribution.

## Abstract

We present an overview and the first results from a large-scale pulsar timing programme that is part of the UTMOST project at the refurbished Molonglo Observatory Synthesis Radio Telescope (MOST) near Canberra, Australia. We currently observe more than 400 mainly bright southern radio pulsars with up to daily cadences. For 205 (8 in binaries, 4 millisecond pulsars) we publish updated timing models, together with their flux densities, flux density variability, and pulse widths at 843 MHz, derived from observations spanning between 1.4 and 3 yr. In comparison with the ATNF pulsar catalogue, we improve the precision of the rotational and astrometric parameters for 123 pulsars, for 47 by at least an order of magnitude. The time spans between our measurements and those in the literature are up to 48 yr, which allows us to investigate their long-term spin-down history and to estimate proper motions for 60 pulsars, of which 24 are newly determined and most are major improvements. The results are consistent with interferometric measurements from the literature. A model with two Gaussian components centred at 139 and $463~\text{km} \: \text{s}^{-1}$ fits the transverse velocity distribution best. The pulse duty cycle distributions at 50 and 10 per cent maximum are best described by log-normal distributions with medians of 2.3 and 4.4 per cent, respectively. We discuss two pulsars that exhibit spin-down rate changes and drifting subpulses. Finally, we describe the autonomous observing system and the dynamic scheduler that has increased the observing efficiency by a factor of 2-3 in comparison with static scheduling.