PhD position in radio transient astronomy

Recent advancements in technology have enabled astronomers to digitize the radio sky down to a fraction of a second. This unprecedented time resolution provides sensitivity to transient phenomena to which we would have otherwise been blind. A great example is Long Period Transients (LPTs) — an emerging and novel class of coherent radio sources that challenge our understanding of neutron star emission physics. Unlike canonical pulsars, which exhibit rotational periods of milliseconds to a few seconds, LPTs show periodic emission on timescales of tens of seconds to minutes and even hours. The discovery of LPTs is entirely unexpected; it has long been thought that as neutron stars spin down and gradually lose rotational energy, pair production and coherent radio emission should cease beyond the so-called “pulsar death line”.

The existence of such long-period emitters raises fundamental questions about how coherent emission is generated in magnetospheres when the available potential drop would be insufficient to sustain pair cascades. To date, only about a dozen LPTs have been uncovered, although the extreme intermittent nature of many of them suggests that many more such objects are yet to be detected. Understanding LPTs is critical for advancing models of neutron star magnetospheres, testing the limits of particle acceleration and plasma generation, and potentially uncovering evolutionary links between pulsars, magnetars, and other transient radio phenomena such as Fast Radio Bursts (FRBs). In short, studying LPTs provides a unique opportunity to probe both the physics of coherent emission and the late-time evolution of neutron stars. It also provides the opportunity to study white dwarf binary systems, since at least some of the LPTs appear to be interacting ‘polar’ systems in which a magnetic bridge forms between a white dwarf and another, low-mass star.

In order to increase the LPT sample size to obtain a more complete picture, we will exploit the plethora of data of the upcoming CHORD radio telescope, a next-generation facility currently being constructed in Canada and is expected to come online in 2027. Thanks to recent advancements in technology, CHORD will have two unique capabilities: an unprecedented sky mapping speed as well as daily repeated sky coverage, the two key ingredients for a successful pulsar survey. 

This project is fully funded by the ANR French national grant. The PhD student will be involved in the optimization and fine-tuning of specific modules of signal processing algorithms, time series data processing and modeling, and/or the exploitation of Machine Learning (ML) based algorithms to reduce false positives caused by human-generated interference signals in the observational data as opposed to genuine astrophysical signals. The candidate will also help manage the data processing and the assessment of the search output. At the end of the PhD, we expect the student to become fully proficient in radio astronomical signal processing and an expert in time domain data analysis, particularly in the area of pulsars and fast transients. The candidate will work on follow-ups of discoveries using the Nançay Radio Telescope (NRT) and the NenuFAR telescope at the Nançay Radio Astronomical Observatory in France. 

Email for any questions and reference letter submission: cherry.ng-guiheneuf [AT] cnrs-orleans.fr

The candidate will be hosted by the ASTRO team at the LPC2E in Orleans. The team boasts the largest pulsar research group in France and is closely affiliated with the Nançay Radio Astronomical Observatory in the Forest of Sologne. 

The CHORD collaboration (https://www.chord-observatory.ca) is a multi-institutional team with over 100 members. Partnering institutes include the University of Toronto, McGill, Perimeter Institute, University of British Columbia, MIT, INAF, and CNRS, among others. The core array of the CHORD telescope is hosted at the Dominion Radio Astrophysical Observatory (DRAO) on the West Coast of Canada, with two outrigger stations to be built at the Green Bank and Hat Creek Observatories in the US. 

Applicants should have an undergraduate and/or master’s degree in Astronomy (or closely related fields), full-time commitment, and a good command of the English language. Previous research experience is beneficial.