papers

Publications (11)

astro-ph.HE2026

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…

astro-ph.HE2026

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…

astro-ph.HE2023

The NANOGrav 15-year Data Set: Evidence for a Gravitational-Wave Background

Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +111

We report multiple lines of evidence for a stochastic signal that is correlated among 67 pulsars from the 15-year pulsar-timing data set collected by the North American Nanohertz O…

astro-ph.CO2026

The NANOGrav 15 yr Data Set: Impacts of Customized Chromatic Noise Models on Gravitational Wave Analyses

Nikita Agarwal, Gabriella Agazie, Alessandra Amosso +120

We report updated nHz gravitational wave (GW) significance, characterization, and interpretations using the customized chromatic-noise models (CNMs) developed in Larsen, Baier et a…

astro-ph.HE2023

The NANOGrav 15-year Data Set: Bayesian Limits on Gravitational Waves from Individual Supermassive Black Hole Binaries

Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +96

Evidence for a low-frequency stochastic gravitational wave background has recently been reported based on analyses of pulsar timing array data. The most likely source of such a bac…

astro-ph.HE2025

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…

gr-qc2023

The NANOGrav 12.5-year Data Set: Search for Gravitational Wave Memory

Gabriella Agazie, Zaven Arzoumanian, Paul T. Baker +87

We present the results of a Bayesian search for gravitational wave (GW) memory in the NANOGrav 12.5-yr data set. We find no convincing evidence for any gravitational wave memory si…

astro-ph.HE2023

The NANOGrav 15-year Data Set: Constraints on Supermassive Black Hole Binaries from the Gravitational Wave Background

Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +111

The NANOGrav 15-year data set shows evidence for the presence of a low-frequency gravitational-wave background (GWB). While many physical processes can source such low-frequency gr…

astro-ph.HE2026

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…

astro-ph.HE2023

The NANOGrav 15-year Data Set: Search for Signals from New Physics

Adeela Afzal, Gabriella Agazie, Akash Anumarlapudi +120

The 15-year pulsar timing data set collected by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) shows positive evidence for the presence of a low-freque…

gr-qc2023

The NANOGrav 15-year data set: Search for Transverse Polarization Modes in the Gravitational-Wave Background

Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +96

Recently we found compelling evidence for a gravitational wave background with Hellings and Downs (HD) correlations in our 15-year data set. These correlations describe gravitation…