The NANOGrav 12.5 yr Data Set: A Computationally Efficient Eccentric Binary Search Pipeline and Constraints on an Eccentric Supermassive Binary Candidate in 3C 66B

Agazie, Gabriella; Arzoumanian, Zaven; Baker, Paul T.; Bécsy, Bence; Blecha, Laura; Blumer, Harsha; Brazier, Adam; Brook, Paul R.; Burke-Spolaor, Sarah; Casey-Clyde, J. Andrew; Charisi, Maria; Chatterjee, Shami; Cheeseboro, Belinda D.; Cohen, Tyler; Cordes, James M.; Cornish, Neil J.; Crawford, Fronefield; Cromartie, H. Thankful; DeCesar, Megan E.; Demorest, Paul B.; Dey, Lankeswar; Dolch, Timothy; Ellis, Justin A.; Ferdman, Robert D.; Ferrara, Elizabeth C.; Fiore, William; Fonseca, Emmanuel; Freedman, Gabriel E.; Garver-Daniels, Nate; Gentile, Peter A.; Glaser, Joseph; Good, Deborah C.; Gopakumar, Achamveedu; Gültekin, Kayhan; Hazboun, Jeffrey S.; Jennings, Ross J.; Johnson, Aaron D.; Jones, Megan L.; Kaiser, Andrew R.; Kaplan, David L.; Kelley, Luke Zoltan; Key, Joey S.; Laal, Nima; Lam, Michael T.; Lamb, William G.; W. Lazio, T. Joseph; Lewandowska, Natalia; Liu, Tingting; Lorimer, Duncan R.; Luo, Jing; Lynch, Ryan S.; Ma, Chung Pei; Madison, Dustin R.; McEwen, Alexander; McKee, Jam...

Abstract

The radio galaxy 3C 66B has been hypothesized to host a supermassive black hole binary (SMBHB) at its center based on electromagnetic observations. Its apparent 1.05 yr period and low redshift (∼0.02) make it an interesting testbed to search for low-frequency gravitational waves (GWs) using pulsar timing array (PTA) experiments. This source has been subjected to multiple searches for continuous GWs from a circular SMBHB, resulting in progressively more stringent constraints on its GW amplitude and chirp mass. In this paper, we develop a pipeline for performing Bayesian targeted searches for eccentric SMBHBs in PTA data sets, and test its efficacy by applying it to simulated data sets with varying injected signal strengths. We also search for a realistic eccentric SMBHB source in 3C 66B using the NANOGrav 12.5 yr data set employing PTA signal models containing Earth term-only as well as Earth+pulsar term contributions using this pipeline. Due to limitations in our PTA signal model, we get meaningful results only when the initial eccentricity e 0 < 0.5 and the symmetric mass ratio η > 0.1. We find no evidence for an eccentric SMBHB signal in our data, and therefore place 95% upper limits on the PTA signal amplitude of 88.1 ± 3.7 ns for the Earth term-only and 81.74 ± 0.86 ns for the Earth+pulsar term searches for e 0 < 0.5 and η > 0.1. Similar 95% upper limits on the chirp mass are (1.98 ± 0.05) × 109 and (1.81 ± 0.01) × 109 M ☉. These upper limits, while less stringent than those calculated from a circular binary search in the NANOGrav 12.5 yr data set, are consistent with the SMBHB model of 3C 66B developed from electromagnetic observations.

Citation

Agazie, G., Arzoumanian, Z., Baker, P. T., Bécsy, B., Blecha, L., Blumer, H., Brazier, A., Brook, P. R., Burke-Spolaor, S., Casey-Clyde, J. A., Charisi, M., Chatterjee, S., Cheeseboro, B. D., Cohen, T., Cordes, J. M., Cornish, N. J., Crawford, F., Cromartie, H. T., DeCesar, M. E., Demorest, P. B., …The NANOGrav Collaboration. (2024). The NANOGrav 12.5 yr Data Set: A Computationally Efficient Eccentric Binary Search Pipeline and Constraints on an Eccentric Supermassive Binary Candidate in 3C 66B. The Astrophysical journal, 963(2), 144. https://doi.org/10.3847/1538-4357/ad1f61

• Journal Article Type: Article
• Acceptance Date: Jan 15, 2024
• Online Publication Date: Mar 7, 2024
• Publication Date: Mar 1, 2024
• Deposit Date: Mar 11, 2024
• Publicly Available Date: Mar 12, 2024
• Journal: Astrophysical Journal
• Print ISSN: 0004-637X
• Electronic ISSN: 1538-4357
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 963
• Issue: 2
• Pages: 144
• DOI: https://doi.org/10.3847/1538-4357/ad1f61
• Keywords: Space and Planetary Science; Astronomy and Astrophysics
• Public URL: https://hull-repository.worktribe.com/output/4586418
• Additional Information: Article Title: The NANOGrav 12.5 yr Data Set: A Computationally Efficient Eccentric Binary Search Pipeline and Constraints on an Eccentric Supermassive Binary Candidate in 3C 66B; Journal Title: The Astrophysical Journal; Article Type: paper; Copyright Information: © 2024. The Author(s). Published by the American Astronomical Society.; Date Received: 2023-09-27; Date Accepted: 2024-01-15; Online publication date: 2024-03-07