Peer-reviewedCC BYThe Astrophysical Journal
The NANOGrav 15 yr and 20 yr Datasets: Timing Events and Pulse Shape Changes
Abstract
The average pulse shape of a pulsar is typically stable over decadal timescales, enabling estimation of pulse times of arrival to better than a small fraction of the pulse width using matched filtering techniques. However, in North American Nanohertz Observatory for Gravitational Waves (NANOGrav) observations of PSR J1713+0747, three discrete timing events that depart from the prevailing timing model have been seen in the last 20 yr. All three correspond to morphological changes in pulse shape. Using principal component analysis, we analyze the pulse profiles of nine NANOGrav pulsars, including seven with profiles from the 15 yr data set and two with additional profiles from the forthcoming 20 yr data set. We recover the three known pulse shape change events in PSR J1713+0747 and another previously known event in PSR J1643−1224. We implement a ranking metric for candidate events and address four highly ranked candidates in this nine-pulsar sample. We also recover known slow pulse shape variations in PSR J1643−1224, PSR J1903+0327, and PSR B1937+21 and report an unexpected recurrence after ∼10 yr of one such variation in PSR B1937+21.
Related
- The NANOGrav 15 yr Dataset: Modified Functional Forms for Profile-Evolution Time Delays in Pulsar Timing Models
- Exact equivalence of the observed redshift and the pulsar timing modulation in the infinitesimal-pulse limit
- Study of pulse jitter characteristics of PSR J1744-1134: Towards high precision pulsar timing with InPTA
- Mitigating the Timing Impact of Anomalous Pulse Profile Shape Variability in PSR J1713+0747 with Gaussian Component Modeling
- Gravitational-wave background from supermassive black holes without merger trees: Tidally regulated mergers and direct inference from the NANOGrav 15 yr data
BibTeX
@article{jacobsonbell2026nanograv,
title = {{The NANOGrav 15 yr and 20 yr Datasets: Timing Events and Pulse Shape Changes}},
author = {Ben Jacobson-Bell and James Cordes and Shami Chatterjee and Sashabaw Niedbalski and Gabriella Agazie and Akash Anumarlapudi and Anne Archibald and Zaven Arzoumanian and Jeremy Baier and Paul Baker and Paul Brook and H. Thankful Cromartie and Kathryn Crowter and Megan Decesar and Paul Demorest and Lankeswar Dey and Timothy Dolch and Elizabeth Ferrara and William Fiore and Emmanuel Fonseca and Gabriel Freedman and Nate Garver-Daniels and Peter Gentile and Joseph Glaser and Deborah Good and Jeffrey Hazboun and Ross Jennings and Megan Jones and David Kaplan and Matthew Kerr and Michael Lam and Bjorn Larsen and Duncan Lorimer and Georgia Lowes and Jing Luo and Ryan Lynch and Ashley Martsen and Alexander Mcewen and Maura Mclaughlin and Natasha Mcmann and Bradley Meyers and Patrick Meyers and Cherry Ng and Mason Ng and David Nice and Shania Nichols and Daniel Oliver and Timothy Pennucci and Benetge Perera and Nihan Pol and Henri Radovan and Scott Ransom and Paul Ray and Alexander Saffer and Ann Schmiedekamp and Carl Schmiedekamp and Brent Shapiro-Albert and Ingrid Stairs and Kevin Stovall and Abhimanyu Susobhanan},
journal = {The Astrophysical Journal},
year = {2026},
month = jun,
doi = {10.3847/1538-4357/ae6db6},
url = {https://hal.science/hal-05842588v1},
note = {CC BY},
}
RIS
TY - JOUR
TI - The NANOGrav 15 yr and 20 yr Datasets: Timing Events and Pulse Shape Changes
AU - Ben Jacobson-Bell
AU - James Cordes
AU - Shami Chatterjee
AU - Sashabaw Niedbalski
AU - Gabriella Agazie
AU - Akash Anumarlapudi
AU - Anne Archibald
AU - Zaven Arzoumanian
AU - Jeremy Baier
AU - Paul Baker
AU - Paul Brook
AU - H. Thankful Cromartie
AU - Kathryn Crowter
AU - Megan Decesar
AU - Paul Demorest
AU - Lankeswar Dey
AU - Timothy Dolch
AU - Elizabeth Ferrara
AU - William Fiore
AU - Emmanuel Fonseca
AU - Gabriel Freedman
AU - Nate Garver-Daniels
AU - Peter Gentile
AU - Joseph Glaser
AU - Deborah Good
AU - Jeffrey Hazboun
AU - Ross Jennings
AU - Megan Jones
AU - David Kaplan
AU - Matthew Kerr
AU - Michael Lam
AU - Bjorn Larsen
AU - Duncan Lorimer
AU - Georgia Lowes
AU - Jing Luo
AU - Ryan Lynch
AU - Ashley Martsen
AU - Alexander Mcewen
AU - Maura Mclaughlin
AU - Natasha Mcmann
AU - Bradley Meyers
AU - Patrick Meyers
AU - Cherry Ng
AU - Mason Ng
AU - David Nice
AU - Shania Nichols
AU - Daniel Oliver
AU - Timothy Pennucci
AU - Benetge Perera
AU - Nihan Pol
AU - Henri Radovan
AU - Scott Ransom
AU - Paul Ray
AU - Alexander Saffer
AU - Ann Schmiedekamp
AU - Carl Schmiedekamp
AU - Brent Shapiro-Albert
AU - Ingrid Stairs
AU - Kevin Stovall
AU - Abhimanyu Susobhanan
PY - 2026
DA - 2026/06/24
JO - The Astrophysical Journal
DO - 10.3847/1538-4357/ae6db6
UR - https://hal.science/hal-05842588v1
AB - The average pulse shape of a pulsar is typically stable over decadal timescales, enabling estimation of pulse times of arrival to better than a small fraction of the pulse width using matched filtering techniques. However, in North American Nanohertz Observatory for Gravitational Waves (NANOGrav) observations of PSR J1713+0747, three discrete timing events that depart from the prevailing timing model have been seen in the last 20 yr. All three correspond to morphological changes in pulse shape. Using principal component analysis, we analyze the pulse profiles of nine NANOGrav pulsars, including seven with profiles from the 15 yr data set and two with additional profiles from the forthcoming 20 yr data set. We recover the three known pulse shape change events in PSR J1713+0747 and another previously known event in PSR J1643−1224. We implement a ranking metric for candidate events and address four highly ranked candidates in this nine-pulsar sample. We also recover known slow pulse shape variations in PSR J1643−1224, PSR J1903+0327, and PSR B1937+21 and report an unexpected recurrence after ∼10 yr of one such variation in PSR B1937+21.
SN - 0004-637X
SN - 1538-4357
ER -