After large galaxies merge, their central supermassive black holes are expected to form binary systems. Their orbital motion should generate a gravitational wave background (GWB) at nanohertz frequencies. Searches for this background use pulsar timing arrays, which perform long-term monitoring of millisecond pulsars at radio wavelengths. We used 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 × 10-14 at a frequency of 1 year-1. The sensitivity is expected to scale with tobs, the observing time span, as [Formula: see text]. This direct measurement provides an independent probe of the GWB while offering a check on radio noise models.
A gamma-ray pulsar timing array constrains the nanohertz gravitational wave background / Ajello, M., Atwood, W.B., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Bellazzini, R., Berretta, A., Bhattacharyya, B., Bissaldi, E., Blandford, R.D., Bloom, E., Bonino, R., Bruel, P., Buehler, R., Burns, E., Buson, S., Cameron, R.A., Caraveo, P.A., Cavazzuti, E., et al.. - In: SCIENCE. - ISSN 0036-8075. - 376:6592(2022), pp. 521-523. [10.1126/science.abm3231]
A gamma-ray pulsar timing array constrains the nanohertz gravitational wave background
E. BissaldiMembro del Collaboration Group
;N. GigliettoMembro del Collaboration Group
;R. PilleraMembro del Collaboration Group
;
2022
Abstract
After large galaxies merge, their central supermassive black holes are expected to form binary systems. Their orbital motion should generate a gravitational wave background (GWB) at nanohertz frequencies. Searches for this background use pulsar timing arrays, which perform long-term monitoring of millisecond pulsars at radio wavelengths. We used 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 × 10-14 at a frequency of 1 year-1. The sensitivity is expected to scale with tobs, the observing time span, as [Formula: see text]. This direct measurement provides an independent probe of the GWB while offering a check on radio noise models.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
