The NANOGrav 15 Yr Data Set: Removing Pulsars One by One from the Pulsar Timing Array

Gabriella Agazie; Akash Anumarlapudi; Anne M. Archibald; Zaven Arzoumanian; Jeremy G. Baier; Paul T. Baker; Bence Bécsy; Laura Blecha; Adam Brazier; Paul R. Brook; Sarah Burke-Spolaor; J. Andrew Casey-Clyde; Maria Charisi; Shami Chatterjee; Tyler Cohen; James M. Cordes; Neil J. Cornish; Fronefield Crawford; H. Thankful Cromartie; Kathryn Crowter; Megan E. DeCesar; Paul B. Demorest; Heling Deng; Lankeswar Dey; Timothy Dolch; Elizabeth C. Ferrara; William Fiore; Emmanuel Fonseca; Gabriel E. Freedman; Emiko C. Gardiner; Nate Garver-Daniels; Peter A. Gentile; Kyle A. Gersbach; Joseph Glaser; Deborah C. Good; Lydia Guertin; Kayhan Gültekin; Jeffrey S. Hazboun; Ross J. Jennings; Aaron D. Johnson; Megan L. Jones; Andrew R. Kaiser; David L. Kaplan; Luke Zoltan Kelley; Matthew Kerr; Joey S. Key; Nima Laal; Michael T. Lam; William G. Lamb; Bjorn Larsen; T. Joseph W. Lazio; Natalia Lewandowska; Tingting Liu; Duncan R. Lorimer; Jing Luo; Ryan S. Lynch; Chung Pei Ma; Dustin R. Madison; Alexander McEwen; James W. McKee; Maura A. McLaughlin; Natasha McMann; Bradley W. Meyers; Patrick M. Meyers; Hannah Middleton; Chiara M.F. Mingarelli; Andrea Mitridate; Christopher J. Moore; Cherry Ng; David J. Nice; Stella Koch Ocker; Ken D. Olum; Timothy T. Pennucci; Benetge B.P. Perera; Nihan S. Pol; Henri A. Radovan; Scott M. Ransom; Paul S. Ray; Joseph D. Romano; Jessie C. Runnoe; Alexander Saffer; Shashwat C. Sardesai; Ann Schmiedekamp; Carl Schmiedekamp; Kai Schmitz; Brent J. Shapiro-Albert; Xavier Siemens; Joseph Simon; Magdalena S. Siwek; Sophia V. Sosa Fiscella; Ingrid H. Stairs; Daniel R. Stinebring; Kevin Stovall; Abhimanyu Susobhanan; Joseph K. Swiggum; Stephen R. Taylor; Jacob E. Turner; Caner Unal; Michele Vallisneri; Alberto Vecchio; Sarah J. Vigeland; Haley M. Wahl; Caitlin A. Witt; David Wright; Olivia Young

doi:10.3847/1538-4357/ad93aa

The NANOGrav 15 Yr Data Set: Removing Pulsars One by One from the Pulsar Timing Array

Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald, Zaven Arzoumanian, Jeremy G. Baier, Paul T. Baker, Bence Bécsy, Laura Blecha, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, J. Andrew Casey-Clyde, Maria Charisi, Shami Chatterjee, Tyler Cohen, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn CrowterMegan E. DeCesar, Paul B. Demorest, Heling Deng, Lankeswar Dey, Timothy Dolch, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Gabriel E. Freedman, Emiko C. Gardiner, Nate Garver-Daniels, Peter A. Gentile, Kyle A. Gersbach, Joseph Glaser, Deborah C. Good, Lydia Guertin, Kayhan Gültekin, Jeffrey S. Hazboun, Ross J. Jennings, Aaron D. Johnson, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Luke Zoltan Kelley, Matthew Kerr, Joey S. Key, Nima Laal, Michael T. Lam, William G. Lamb, Bjorn Larsen, T. Joseph W. Lazio, Natalia Lewandowska, Tingting Liu, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, Chung Pei Ma, Dustin R. Madison, Alexander McEwen, James W. McKee, Maura A. McLaughlin, Natasha McMann, Bradley W. Meyers, Patrick M. Meyers, Hannah Middleton, Chiara M.F. Mingarelli, Andrea Mitridate, Christopher J. Moore, Cherry Ng, David J. Nice, Stella Koch Ocker, Ken D. Olum, Timothy T. Pennucci, Benetge B.P. Perera, Nihan S. Pol, Henri A. Radovan, Scott M. Ransom, Paul S. Ray, Joseph D. Romano, Jessie C. Runnoe, Alexander Saffer, Shashwat C. Sardesai, Ann Schmiedekamp, Carl Schmiedekamp, Kai Schmitz, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Magdalena S. Siwek, Sophia V. Sosa Fiscella, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Abhimanyu Susobhanan, Joseph K. Swiggum, Stephen R. Taylor, Jacob E. Turner, Caner Unal, Michele Vallisneri, Alberto Vecchio, Sarah J. Vigeland, Haley M. Wahl, Caitlin A. Witt, David Wright, Olivia Young

Research output: Contribution to journal › Article › peer-review

Abstract

Evidence has emerged for a stochastic signal correlated among 67 pulsars within the 15 yr pulsar-timing data set compiled by the NANOGrav collaboration. Similar signals have been found in data from the European, Indian, Parkes, and Chinese pulsar timing arrays. This signal has been interpreted as indicative of the presence of a nanohertz stochastic gravitational-wave background (GWB). To explore the internal consistency of this result, we investigate how the recovered signal strength changes as we remove the pulsars one by one from the data set. We calculate the signal strength using the (noise-marginalized) optimal statistic, a frequentist metric designed to measure the correlated excess power in the residuals of the arrival times of the radio pulses. We identify several features emerging from this analysis that were initially unexpected. The significance of these features, however, can only be assessed by comparing the real data to synthetic data sets. After conducting identical analyses on simulated data sets, we do not find anything inconsistent with the presence of a stochastic GWB in the NANOGrav 15 yr data. The methodologies developed here can offer additional tools for application to future, more sensitive data sets. While this analysis provides an internal consistency check of the NANOGrav results, it does not eliminate the necessity for additional investigations that could identify potential systematics or uncover unmodeled physical phenomena in the data.

Original language	English (US)
Article number	168
Journal	Astrophysical Journal
Volume	978
Issue number	2
DOIs	https://doi.org/10.3847/1538-4357/ad93aa
State	Published - Jan 1 2025

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

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10.3847/1538-4357/ad93aa

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Agazie, G., Anumarlapudi, A., Archibald, A. M., Arzoumanian, Z., Baier, J. G., Baker, P. T., Bécsy, B., Blecha, L., Brazier, A., Brook, P. R., Burke-Spolaor, S., Casey-Clyde, J. A., Charisi, M., Chatterjee, S., Cohen, T., Cordes, J. M., Cornish, N. J., Crawford, F., Cromartie, H. T., ... Young, O. (2025). The NANOGrav 15 Yr Data Set: Removing Pulsars One by One from the Pulsar Timing Array. Astrophysical Journal, 978(2), Article 168. https://doi.org/10.3847/1538-4357/ad93aa

@article{d1258189a39a4b84bf3205126799660d,

title = "The NANOGrav 15 Yr Data Set: Removing Pulsars One by One from the Pulsar Timing Array",

abstract = "Evidence has emerged for a stochastic signal correlated among 67 pulsars within the 15 yr pulsar-timing data set compiled by the NANOGrav collaboration. Similar signals have been found in data from the European, Indian, Parkes, and Chinese pulsar timing arrays. This signal has been interpreted as indicative of the presence of a nanohertz stochastic gravitational-wave background (GWB). To explore the internal consistency of this result, we investigate how the recovered signal strength changes as we remove the pulsars one by one from the data set. We calculate the signal strength using the (noise-marginalized) optimal statistic, a frequentist metric designed to measure the correlated excess power in the residuals of the arrival times of the radio pulses. We identify several features emerging from this analysis that were initially unexpected. The significance of these features, however, can only be assessed by comparing the real data to synthetic data sets. After conducting identical analyses on simulated data sets, we do not find anything inconsistent with the presence of a stochastic GWB in the NANOGrav 15 yr data. The methodologies developed here can offer additional tools for application to future, more sensitive data sets. While this analysis provides an internal consistency check of the NANOGrav results, it does not eliminate the necessity for additional investigations that could identify potential systematics or uncover unmodeled physical phenomena in the data.",

author = "Gabriella Agazie and Akash Anumarlapudi and Archibald, {Anne M.} and Zaven Arzoumanian and Baier, {Jeremy G.} and Baker, {Paul T.} and Bence B{\'e}csy and Laura Blecha and Adam Brazier and Brook, {Paul R.} and Sarah Burke-Spolaor and Casey-Clyde, {J. Andrew} and Maria Charisi and Shami Chatterjee and Tyler Cohen and Cordes, {James M.} and Cornish, {Neil J.} and Fronefield Crawford and Cromartie, {H. Thankful} and Kathryn Crowter and DeCesar, {Megan E.} and Demorest, {Paul B.} and Heling Deng and Lankeswar Dey and Timothy Dolch and Ferrara, {Elizabeth C.} and William Fiore and Emmanuel Fonseca and Freedman, {Gabriel E.} and Gardiner, {Emiko C.} and Nate Garver-Daniels and Gentile, {Peter A.} and Gersbach, {Kyle A.} and Joseph Glaser and Good, {Deborah C.} and Lydia Guertin and Kayhan G{\"u}ltekin and Hazboun, {Jeffrey S.} and Jennings, {Ross J.} and Johnson, {Aaron D.} and Jones, {Megan L.} and Kaiser, {Andrew R.} and Kaplan, {David L.} and Kelley, {Luke Zoltan} and Matthew Kerr and Key, {Joey S.} and Nima Laal and Lam, {Michael T.} and Lamb, {William G.} and Bjorn Larsen and Lazio, {T. Joseph W.} and Natalia Lewandowska and Tingting Liu and Lorimer, {Duncan R.} and Jing Luo and Lynch, {Ryan S.} and Ma, {Chung Pei} and Madison, {Dustin R.} and Alexander McEwen and McKee, {James W.} and McLaughlin, {Maura A.} and Natasha McMann and Meyers, {Bradley W.} and Meyers, {Patrick M.} and Hannah Middleton and Mingarelli, {Chiara M.F.} and Andrea Mitridate and Moore, {Christopher J.} and Cherry Ng and Nice, {David J.} and Ocker, {Stella Koch} and Olum, {Ken D.} and Pennucci, {Timothy T.} and Perera, {Benetge B.P.} and Pol, {Nihan S.} and Radovan, {Henri A.} and Ransom, {Scott M.} and Ray, {Paul S.} and Romano, {Joseph D.} and Runnoe, {Jessie C.} and Alexander Saffer and Sardesai, {Shashwat C.} and Ann Schmiedekamp and Carl Schmiedekamp and Kai Schmitz and Shapiro-Albert, {Brent J.} and Xavier Siemens and Joseph Simon and Siwek, {Magdalena S.} and {Sosa Fiscella}, {Sophia V.} and Stairs, {Ingrid H.} and Stinebring, {Daniel R.} and Kevin Stovall and Abhimanyu Susobhanan and Swiggum, {Joseph K.} and Taylor, {Stephen R.} and Turner, {Jacob E.} and Caner Unal and Michele Vallisneri and Alberto Vecchio and Vigeland, {Sarah J.} and Wahl, {Haley M.} and Witt, {Caitlin A.} and David Wright and Olivia Young",

note = "Publisher Copyright: {\textcopyright} 2025. The Author(s). Published by the American Astronomical Society.",

year = "2025",

month = jan,

day = "1",

doi = "10.3847/1538-4357/ad93aa",

language = "English (US)",

volume = "978",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

number = "2",

}

Agazie, G, Anumarlapudi, A, Archibald, AM, Arzoumanian, Z, Baier, JG, Baker, PT, Bécsy, B, Blecha, L, Brazier, A, Brook, PR, Burke-Spolaor, S, Casey-Clyde, JA, Charisi, M, Chatterjee, S, Cohen, T, Cordes, JM, Cornish, NJ, Crawford, F, Cromartie, HT, Crowter, K, DeCesar, ME, Demorest, PB, Deng, H, Dey, L, Dolch, T, Ferrara, EC, Fiore, W, Fonseca, E, Freedman, GE, Gardiner, EC, Garver-Daniels, N, Gentile, PA, Gersbach, KA, Glaser, J, Good, DC, Guertin, L, Gültekin, K, Hazboun, JS, Jennings, RJ, Johnson, AD, Jones, ML, Kaiser, AR, Kaplan, DL, Kelley, LZ, Kerr, M, Key, JS, Laal, N, Lam, MT, Lamb, WG, Larsen, B, Lazio, TJW, Lewandowska, N, Liu, T, Lorimer, DR, Luo, J, Lynch, RS, Ma, CP, Madison, DR, McEwen, A, McKee, JW, McLaughlin, MA, McMann, N, Meyers, BW, Meyers, PM, Middleton, H, Mingarelli, CMF, Mitridate, A, Moore, CJ, Ng, C, Nice, DJ, Ocker, SK, Olum, KD, Pennucci, TT, Perera, BBP, Pol, NS, Radovan, HA, Ransom, SM, Ray, PS, Romano, JD, Runnoe, JC, Saffer, A, Sardesai, SC, Schmiedekamp, A, Schmiedekamp, C, Schmitz, K, Shapiro-Albert, BJ, Siemens, X, Simon, J, Siwek, MS, Sosa Fiscella, SV, Stairs, IH, Stinebring, DR, Stovall, K, Susobhanan, A, Swiggum, JK, Taylor, SR, Turner, JE, Unal, C, Vallisneri, M, Vecchio, A, Vigeland, SJ, Wahl, HM, Witt, CA, Wright, D & Young, O 2025, 'The NANOGrav 15 Yr Data Set: Removing Pulsars One by One from the Pulsar Timing Array', Astrophysical Journal, vol. 978, no. 2, 168. https://doi.org/10.3847/1538-4357/ad93aa

TY - JOUR

T1 - The NANOGrav 15 Yr Data Set

T2 - Removing Pulsars One by One from the Pulsar Timing Array

AU - Agazie, Gabriella

AU - Anumarlapudi, Akash

AU - Archibald, Anne M.

AU - Arzoumanian, Zaven

AU - Baier, Jeremy G.

AU - Baker, Paul T.

AU - Bécsy, Bence

AU - Blecha, Laura

AU - Brazier, Adam

AU - Brook, Paul R.

AU - Burke-Spolaor, Sarah

AU - Casey-Clyde, J. Andrew

AU - Charisi, Maria

AU - Chatterjee, Shami

AU - Cohen, Tyler

AU - Cordes, James M.

AU - Cornish, Neil J.

AU - Crawford, Fronefield

AU - Cromartie, H. Thankful

AU - Crowter, Kathryn

AU - DeCesar, Megan E.

AU - Demorest, Paul B.

AU - Deng, Heling

AU - Dey, Lankeswar

AU - Dolch, Timothy

AU - Ferrara, Elizabeth C.

AU - Fiore, William

AU - Fonseca, Emmanuel

AU - Freedman, Gabriel E.

AU - Gardiner, Emiko C.

AU - Garver-Daniels, Nate

AU - Gentile, Peter A.

AU - Gersbach, Kyle A.

AU - Glaser, Joseph

AU - Good, Deborah C.

AU - Guertin, Lydia

AU - Gültekin, Kayhan

AU - Hazboun, Jeffrey S.

AU - Jennings, Ross J.

AU - Johnson, Aaron D.

AU - Jones, Megan L.

AU - Kaiser, Andrew R.

AU - Kaplan, David L.

AU - Kelley, Luke Zoltan

AU - Kerr, Matthew

AU - Key, Joey S.

AU - Laal, Nima

AU - Lam, Michael T.

AU - Lamb, William G.

AU - Larsen, Bjorn

AU - Lazio, T. Joseph W.

AU - Lewandowska, Natalia

AU - Liu, Tingting

AU - Lorimer, Duncan R.

AU - Luo, Jing

AU - Lynch, Ryan S.

AU - Ma, Chung Pei

AU - Madison, Dustin R.

AU - McEwen, Alexander

AU - McKee, James W.

AU - McLaughlin, Maura A.

AU - McMann, Natasha

AU - Meyers, Bradley W.

AU - Meyers, Patrick M.

AU - Middleton, Hannah

AU - Mingarelli, Chiara M.F.

AU - Mitridate, Andrea

AU - Moore, Christopher J.

AU - Ng, Cherry

AU - Nice, David J.

AU - Ocker, Stella Koch

AU - Olum, Ken D.

AU - Pennucci, Timothy T.

AU - Perera, Benetge B.P.

AU - Pol, Nihan S.

AU - Radovan, Henri A.

AU - Ransom, Scott M.

AU - Ray, Paul S.

AU - Romano, Joseph D.

AU - Runnoe, Jessie C.

AU - Saffer, Alexander

AU - Sardesai, Shashwat C.

AU - Schmiedekamp, Ann

AU - Schmiedekamp, Carl

AU - Schmitz, Kai

AU - Shapiro-Albert, Brent J.

AU - Siemens, Xavier

AU - Simon, Joseph

AU - Siwek, Magdalena S.

AU - Sosa Fiscella, Sophia V.

AU - Stairs, Ingrid H.

AU - Stinebring, Daniel R.

AU - Stovall, Kevin

AU - Susobhanan, Abhimanyu

AU - Swiggum, Joseph K.

AU - Taylor, Stephen R.

AU - Turner, Jacob E.

AU - Unal, Caner

AU - Vallisneri, Michele

AU - Vecchio, Alberto

AU - Vigeland, Sarah J.

AU - Wahl, Haley M.

AU - Witt, Caitlin A.

AU - Wright, David

AU - Young, Olivia

PY - 2025/1/1

Y1 - 2025/1/1

N2 - Evidence has emerged for a stochastic signal correlated among 67 pulsars within the 15 yr pulsar-timing data set compiled by the NANOGrav collaboration. Similar signals have been found in data from the European, Indian, Parkes, and Chinese pulsar timing arrays. This signal has been interpreted as indicative of the presence of a nanohertz stochastic gravitational-wave background (GWB). To explore the internal consistency of this result, we investigate how the recovered signal strength changes as we remove the pulsars one by one from the data set. We calculate the signal strength using the (noise-marginalized) optimal statistic, a frequentist metric designed to measure the correlated excess power in the residuals of the arrival times of the radio pulses. We identify several features emerging from this analysis that were initially unexpected. The significance of these features, however, can only be assessed by comparing the real data to synthetic data sets. After conducting identical analyses on simulated data sets, we do not find anything inconsistent with the presence of a stochastic GWB in the NANOGrav 15 yr data. The methodologies developed here can offer additional tools for application to future, more sensitive data sets. While this analysis provides an internal consistency check of the NANOGrav results, it does not eliminate the necessity for additional investigations that could identify potential systematics or uncover unmodeled physical phenomena in the data.

AB - Evidence has emerged for a stochastic signal correlated among 67 pulsars within the 15 yr pulsar-timing data set compiled by the NANOGrav collaboration. Similar signals have been found in data from the European, Indian, Parkes, and Chinese pulsar timing arrays. This signal has been interpreted as indicative of the presence of a nanohertz stochastic gravitational-wave background (GWB). To explore the internal consistency of this result, we investigate how the recovered signal strength changes as we remove the pulsars one by one from the data set. We calculate the signal strength using the (noise-marginalized) optimal statistic, a frequentist metric designed to measure the correlated excess power in the residuals of the arrival times of the radio pulses. We identify several features emerging from this analysis that were initially unexpected. The significance of these features, however, can only be assessed by comparing the real data to synthetic data sets. After conducting identical analyses on simulated data sets, we do not find anything inconsistent with the presence of a stochastic GWB in the NANOGrav 15 yr data. The methodologies developed here can offer additional tools for application to future, more sensitive data sets. While this analysis provides an internal consistency check of the NANOGrav results, it does not eliminate the necessity for additional investigations that could identify potential systematics or uncover unmodeled physical phenomena in the data.

UR - http://www.scopus.com/inward/record.url?scp=85214900588&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85214900588&partnerID=8YFLogxK

U2 - 10.3847/1538-4357/ad93aa

DO - 10.3847/1538-4357/ad93aa

M3 - Article

AN - SCOPUS:85214900588

SN - 0004-637X

VL - 978

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

M1 - 168

ER -

The NANOGrav 15 Yr Data Set: Removing Pulsars One by One from the Pulsar Timing Array

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