A Gamma-ray Pulsar Timing Array Constrains the Nanohertz Gravitational Wave Background
Creators: name: Ajello, M.
name: Atwood, W. B.
name: Baldini, L.
name: Ballet, J.
name: Barbiellini, G.
name: Bastieri, D.
name: Bellazzini, R.
name: Berretta, A.
name: Bhattacharyya, B.
name: Bissaldi, E.
name: Blandford, R. D.
name: Bloom, E.
name: Bonino, R.
name: Bruel, P.
name: Buehler, R.
name: Burns, E.
name: Buson, S.
name: Cameron, R. A.
name: Caraveo, P. A.
name: Cavazzuti, E.
name: Cibrario, N.
name: Ciprini, S.
name: Clark, C. J.
name: Cognard, I.
name: Coronado-Blázquez, J.
name: Crnogorcevic, M.
name: Cromartie, H.
name: Crowter, K.
name: Cutini, S.
name: D'Ammando, F.
name: Gaetano, S. D.
name: Palma, F. d.
name: Digel, S. W.
name: Lalla, N. D.
name: Dirirsa, F. Fan.
name: Venere, L. D.
name: Domínguez, A.
name: Ferrara, E. C.
name: Fiori, A.
name: Franckowiak, A.
name: Fukazawa, Y.
name: Funk, S.
name: Fusco, P.
name: Gammaldi, V.
name: Gargano, F.
name: Gasparrini, D.
name: Giglietto, N.
name: Giordano, F.
name: Giroletti, M.
name: Green, D.
name: Grenier, I. A.
name: Guillemot, L.
name: Guiriec, S.
name: Gustafsson, M.
name: Harding, A. K.
name: Hays, E.
name: Hewitt, J. W.
name: Horan, D.
name: Hou, X.
name: Jóhannesson, G.
name: Keith, M. J.
name: Kerr, M.
name: Kramer, M.
name: Kuss, M.
name: Larsson, S.
name: Latronico, L.
name: Li, J.
name: Longo, F.
name: Loparco, F.
name: Lovellette, M. N.
name: Lubrano, P.
name: Maldera, S.
name: Manfreda, A.
name: Martí-Devesa, G.
name: Mazziotta, M. N.
name: Mereu, I.
name: Michelson, P. F.
name: Mirabal, N.
name: Mitthumsiri, W.
name: Mizuno, T.
name: Monzani, M. E.
name: Morselli, A.
name: Negro, M.
name: Nieder, L.
name: Ojha, R.
name: Omodei, N.
name: Orienti, M.
name: Orlando, E.
name: Ormes, J. F.
name: Paneque, D.
name: Parthasarathy, A.
name: Pei, Z.
name: Persic, M.
name: Pesce-Rollins, M.
name: Pillera, R.
name: Poon, H.
name: Porter, T. A.
name: Principe, G.
name: Racusin, J. L.
name: Rainò, S.
name: Rando, R.
name: Rani, B.
name: Ransom, S. M.
name: Ray, P. S.
name: Razzano, M.
name: Razzaque, S.
name: Reimer, A.
name: Reimer, O.
name: Roy, J.
name: Sánchez-Conde, M.
name: Parkinson, P. M. Sa.
name: Scargle, J.
name: Scotton, L.
name: Serini, D.
name: Sgrò, C.
name: Siskind, E. J.
name: Smith, D. A.
name: Spandre, G.
name: Spiewak, R.
name: Spinelli, P.
name: Stairs, I.
name: Suson, D. J.
name: Swihart, S. J.
name: Tabassum, S.
name: Thayer, J. B.
name: Theureau, G.
name: Torres, D. F.
name: Troja, E.
name: Valverde, J.
name: Wadiasingh, Z.
name: Wood, K.
name: Zaharijas, G.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: After large galaxies merge, their central supermassive black holes are expected to form binary systems whose orbital motion generates a gravitational wave background (GWB) at nanohertz frequencies. Searches for this background utilize pulsar timing arrays, which perform long-term monitoring of millisecond pulsars (MSPs) at radio wavelengths. We use 12.5 years of Fermi Large Area Telescope data to form a gamma-ray pulsar timing array. Results from 35 bright gamma-ray pulsars place a 95\% credible limit on the GWB characteristic strain of $1.0\times10^{-14}$ at 1 yr$^{-1}$, which scales as the observing time span $t_{\mathrm{obs}}^{-13/6}$. This direct measurement provides an independent probe of the GWB while offering a check on radio noise models.
description: 3 figures in the main text. 3 figures and 8 tables are in the supplementary material