GBT24B-998

The North American Nanohertz Observatory for Gravitational Waves

Abstract

In June 2023, the NANOGrav collaboration, along with pulsar timing arrays around the world, presented the first evidence for a stochastic background of low-frequency (nHz) gravitational waves (GWs). By precisely timing arrays of millisecond pulsars (MSPs) and searching for small, spatially-correlated MSP timing perturbations induced by nHz GWs, we obtained strong (3-4 sigma) evidence for this background. As its origin and characteristics are poorly understood, the era of low-frequency GW astrophysics has only just begun. In order to determine if this GW signal originates from supermassive black hole binary (SMBH) mergers, or perhaps from an exotic cosmological phenomenon, NANOGrav must continue timing >70 MSPs at high cadence for many years. After Arecibo's loss, NANOGrav's observing scheme has relied on the GBT, VLA, and CHIME. With continued observations, we are confident that we will not only constrain the spectral characteristics of the GW background (distinguishing between astrophysical models of galaxy evolution), but will also glimpse signals from individual SMBH mergers. We add three MSPs and remove one from our program, and discuss our plan to transition from 820-MHz + L-band observations to the Ultra-Wideband Receiver. Including overhead, our request totals 2205 hours and 168 hours using the GBT and VLA, respectively.

Investigators

Name	Institution
Alexander Saffer	National Radio Astronomy Observatory; West Virginia University
GBT Operator	Green Bank Observatory
Ross Jennings	Cornell University; West Virginia University
Chiara Mingarelli	Yale University
Caitlin Witt	Northwestern University; Adler Planetarium
Sarah Vigeland	Wisconsin at Milwaukee, University of
Daniel Stinebring	Oberlin College
Ingrid Stairs	British Columbia, University of
Sarah Spolaor	West Virginia University
Xavier Siemens	Oregon State University; Wisconsin at Milwaukee, University of
Paul Ray	Naval Research Laboratory
Nihan Pol	Oregon State University; Wisconsin at Milwaukee, University of; Texas Tech University
Stella Ocker	Carnegie Institute of Washington; California Institute of Technology
Maura McLaughlin	West Virginia University
Dustin Madison	National Radio Astronomy Observatory
Georgia Lowes	Hull, University of
Tingting Liu	West Virginia University; Wisconsin at Milwaukee, University of
Natalia Lewandowska	New York at Oswego, State University of
Joe Lazio	Jet Propulsion Laboratory
William Lamb	Vanderbilt University
Michael Lam	Cornell University; Rochester Institute of Technology; West Virginia University; SETI Institute
David Kaplan	Wisconsin at Milwaukee, University of
Lydia Guertin	Academia Sinica
Emmanuel Fonseca	British Columbia, University of; McGill University; West Virginia University
William Fiore	British Columbia, University of; West Virginia University
Elizabeth Ferrara	Goddard Space Flight Center
Timothy Dolch	Cornell University; Oberlin College; Hillsdale College
Fronefield Crawford	Franklin and Marshall College
Jim Cordes	Cornell University
Shami Chatterjee	Cornell University
Paul Baker	West Virginia University; Widener University
Jeremy Baier	Oregon State University
Zaven Arzoumanian	Goddard Space Flight Center
Gabriella Agazie	West Virginia University; Wisconsin at Milwaukee, University of
Ryan Lynch	Green Bank Observatory
Jeffrey Hazboun	Oregon State University; Washington Bothell, University of
Joseph Glaser	West Virginia University
Tyler Cohen	National Radio Astronomy Observatory
David Nice	Lafayette College
Deborah Good	Montana, University of
Paul Demorest	National Radio Astronomy Observatory
Megan DeCesar	George Mason University
Thankful Cromartie *	Cornell University; Virginia, University of; Naval Research Laboratory
Benetge Perera	National Astronomy and Ionosphere Center ; West Virginia University; Florida, University of Central
Jason Ybarra	West Virginia University
Luke Kelley	California at Berkeley, University of
Nima Laal	Vanderbilt University
Scott Ransom	National Radio Astronomy Observatory; Virginia, University of
James McKee	Hull, University of
Stephen Taylor	Vanderbilt University

* indicates the PI