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The NANOGrav 15 yr Dataset: Modified Functional Forms for Profile-Evolution Time Delays in Pulsar Timing Models
Sofia V. Sosa Fiscella, Michael T. Lam, Olivia West +49
Radio pulsars exhibit frequency-dependent variations in the shape of their pulse profiles that introduce systematic delays in the observed pulse times of arrival (TOA) across an ob…
Optimal Pulsar Timing Array Strategies with the Deep Synoptic Array
Tyler Cohen, Paul B. Demorest, Jeremy G. Baier +50
Pulsar timing array (PTA) experiments have seen evidence for a nanohertz-frequency gravitational wave background (GWB) through coordinated radio timing observations of millisecond…
Constraints on Supermassive Black Hole Binaries from the Lack of Resolvable Sources in the NANOGrav 15-yr Dataset
Emiko C. Gardiner, Kayhan Gültekin, Philippe Turgeon +116
Pulsar timing arrays (PTAs) have found evidence of a gravitational wave background (GWB) consistent with a population of supermassive black hole binaries (SMBHBs), but have not yet…
Generalized Non-linear Bayesian Pulsar Timing with Enterprise
Andrew R. Kaiser, Jeffrey S. Hazboun, Maura A. McLaughlin +56
In this study, we use the Bayesian methods in the Enterprise package to examine the fully general parameterization of pulsar timing models in tandem with noise. We investigate four…
Gravitational Wave Measurement of the - Intrinsic Scatter at High Redshift
Cayenne Matt, Kayhan Gültekin, Gabriella Agazie +109
The observed GWB spectrum is higher in amplitude than model predictions by a factor of 2-3. Using a semi-analytic model, we evaluate the effect of a high-scatter supermassive black…
The NANOGrav 15 yr Data Set: Piecewise Power-Law Reconstruction of the Gravitational-Wave Background
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +108
The NANOGrav 15-year (NG15) data set provides evidence for a gravitational-wave background (GWB) signal at nanohertz frequencies, which is expected to originate either from a cosmi…
The NANOGrav 15-Year Data Set: Improved Timing Precision With VLBI Astrometric Priors
Sofia V. Sosa Fiscella, Michael T. Lam, Gabriella Agazie +47
Accurate pulsar astrometric estimates play an essential role in almost all high-precision pulsar timing experiments. Traditional pulsar timing techniques refine these estimates by…
An Extreme Scattering Event Toward PSR J2313+4253
Zachary C. Zelensky, Jacob E. Turner, Juan G. Lebron Medina +7
We present evidence of an extreme scattering event (ESE) toward PSR J2313+4253 using high-cadence observations taken with the Green Bank Observatory 20m telescope. The high density…
CHIME-o-Grav: Wideband Timing of Four Millisecond Pulsars from the NANOGrav 15-yr dataset
Gabriella Agazie, David L. Kaplan, Abhimanyu Susobhanan +50
Wideband timing of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) datasets, where a single time-of-arrival (TOA) and a single dispersion measure (DM) a…
Inferring Mbh-Mbulge Evolution from the Gravitational Wave Background
Cayenne Matt, Kayhan Gultekin, Luke Kelley +104
We test the impact of an evolving supermassive black hole (SMBH) mass scaling relation (Mbh-Mbulge) on the predictions for the gravitational wave background (GWB). The observed GWB…
The NANOGrav 15 yr Data Set: Targeted Searches for Supermassive Black Hole Binaries
Nikita Agarwal, Gabriella Agazie, Akash Anumarlapudi +116
We present the first targeted searches for continuous gravitational waves (CWs) from 114 active galactic nuclei (AGN) that may host supermassive black hole binaries, using the NANO…
The NANOGrav 15-year Data Set: Search for Gravitational Scattering of Pulsars by Free-Floating Objects in Interstellar Space
Lankeswar Dey, Ross J. Jennings, Jackson D. Taylor +48
Free-floating objects (FFOs) in interstellar spacerogue planets, brown dwarfs, and large asteroids that are not gravitationally bound to any starare expected to be ubiquitous…
The NANOGrav 15-Year Data Set: A Case Study for Simplified Dispersion Measure Modeling for PSR J1455-3330 and the Impact on Gravitational Wave Sensitivity
Michael T. Lam, David L. Kaplan, Gabriella Agazie +46
Evidence for a low-frequency gravitational-wave background using pulsar timing arrays has generated recent interest into its underlying contributing sources. However, multiple inve…
Rapid Construction of Joint Pulsar Timing Array Datasets: The Lite Method
Bjorn Larsen, Chiara M. F. Mingarelli, Paul T. Baker +41
The International Pulsar Timing Array (IPTA)'s second data release (IPTA DR2) combines decades of observations of 65 millisecond pulsars from 7 radio telescopes. IPTA datasets shou…
Multifrequency Radio Observations of the Magnetar Swift J1818.0--1607
Evan F. Lewis, Harsha Blumer, Ryan S. Lynch +1
We report on Green Bank Telescope observations of the radio magnetar Swift J1818.0--1607 between 820 MHz and 35 GHz, taken from six to nine months after its 2020 March outburst. We…
Pulse Profile Variability of PSR J1022+1001 in NANOGrav Data
William Fiore, Maura A. McLaughlin, Gabriella Agazie +46
Pulse profile stability is a central assumption of standard pulsar timing methods. Thus, it is important for pulsar timing array experiments such as the North American Nanohertz Ob…
Scintillation Bandwidth Measurements from 23 Pulsars from the AO327 Survey
Sofia Z. Sheikh, Grayce C. Brown, Jackson MacTaggart +15
A pulsar's scintillation bandwidth is inversely proportional to the scattering delay, making accurate measurements of scintillation bandwidth critical to characterize unmitigated d…
The NANOGrav 15 yr Data Set: Harmonic Analysis of the Pulsar Angular Correlations
Gabriella Agazie, Jeremy G. Baier, Paul T. Baker +86
Pulsar timing array observations have found evidence for an isotropic gravitational wave background with the Hellings-Downs angular correlations, expected from general relativity.…
The NANOGrav 12.5-Year Data Set: Probing Interstellar Turbulence and Precision Pulsar Timing with PSR J1903+0327
Abra Geiger, James M. Cordes, Michael T. Lam +33
Free electrons in the interstellar medium refract and diffract radio waves along multiple paths, resulting in angular and temporal broadening of radio pulses that limits pulsar tim…
The NANOGrav 15 Yr Data Set: Removing Pulsars One by One from the Pulsar Timing Array
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +102
Evidence has emerged for a stochastic signal correlated among 67 pulsars within the 15-year pulsar-timing data set compiled by the NANOGrav collaboration. Similar signals have been…
Inference on inner galaxy structure via gravitational waves from supermassive binaries
Yifan Chen, Matthias Daniel, Daniel J. D'Orazio +107
The detection of a stochastic gravitational wave background by pulsar-timing arrays indicates the presence of a population of supermassive black hole binaries. Although the observe…
The NANOGrav 15 yr Data Set: Running of the Spectral Index
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +102
The NANOGrav 15-year data provides compelling evidence for a stochastic gravitational-wave (GW) background at nanohertz frequencies. The simplest model-independent approach to char…
Improving Pulsar Timing Precision with Single Pulse Fluence Clustering
Sofia V. Sosa Fiscella, Michael T. Lam, Maura A. McLaughlin
Traditional pulsar timing techniques involve averaging large numbers of single pulses to obtain a high signal-to-noise (S/N) profile, which is matched to a template to measure a ti…
The NANOGrav 15 yr data set: Posterior predictive checks for gravitational-wave detection with pulsar timing arrays
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +99
Pulsar-timing-array experiments have reported evidence for a stochastic background of nanohertz gravitational waves consistent with the signal expected from a population of superma…