We present results from directed searches for continuous gravitational waves from a sample of 15 nearby supernova remnants, likely hosting young neutron star candidates, using data from the first eight months of the fourth observing run (O4) of the LIGO–Virgo–KAGRA Collaboration. The analysis employs five pipelines: four semicoherent methods—the Band-Sampled-Data directed pipeline, Weave, and two Viterbi pipelines (single- and dual-harmonic)—and PyStoch, a cross-correlation-based pipeline. These searches cover wide frequency bands and do not assume prior knowledge of the targets’ ephemerides. No evidence of a signal is found from any of the 15 sources. We set 95% confidence-level upper limits on the intrinsic strain amplitude, with the most stringent constraints reaching ∼4 × 10−26 near 300 Hz for the nearby source G266.2−1.2 (Vela Jr.). We also derive limits on neutron star ellipticity and r-mode amplitudes for the same source, with the best constraints reaching ≲10−7 and ≲10−5, respectively, at frequencies above 400 Hz. For frequencies above 200 Hz, these results represent the most sensitive wide-band directed searches for continuous gravitational waves from supernova remnants to date. © 2026. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the https://creativecommons.org/licenses/by/4.0/. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Searches for Continuous Gravitational Waves from Supernova Remnants in the First Part of the LIGO-Virgo-KAGRA Fourth Observing Run
Assiduo, M.;Fabrizi, F.;Guidi, G. M.;Longo, A.;Martelli, F.;Mobilia, L.;Montani, M.;Panzeri, M.;Piergiovanni, F.;Vetrano, F.;Viceré, A.;
2026
Abstract
We present results from directed searches for continuous gravitational waves from a sample of 15 nearby supernova remnants, likely hosting young neutron star candidates, using data from the first eight months of the fourth observing run (O4) of the LIGO–Virgo–KAGRA Collaboration. The analysis employs five pipelines: four semicoherent methods—the Band-Sampled-Data directed pipeline, Weave, and two Viterbi pipelines (single- and dual-harmonic)—and PyStoch, a cross-correlation-based pipeline. These searches cover wide frequency bands and do not assume prior knowledge of the targets’ ephemerides. No evidence of a signal is found from any of the 15 sources. We set 95% confidence-level upper limits on the intrinsic strain amplitude, with the most stringent constraints reaching ∼4 × 10−26 near 300 Hz for the nearby source G266.2−1.2 (Vela Jr.). We also derive limits on neutron star ellipticity and r-mode amplitudes for the same source, with the best constraints reaching ≲10−7 and ≲10−5, respectively, at frequencies above 400 Hz. For frequencies above 200 Hz, these results represent the most sensitive wide-band directed searches for continuous gravitational waves from supernova remnants to date. © 2026. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the https://creativecommons.org/licenses/by/4.0/. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
