Allsky, allfrequency directional search for persistent gravitational waves from Advanced LIGO's and Advanced Virgo's first three observing runs
Abstract
We present the first results from an allsky allfrequency (ASAF) search for an anisotropic stochastic gravitationalwave background using the data from the first three observing runs of the Advanced LIGO and Advanced Virgo detectors. Upper limit maps on broadband anisotropies of a persistent stochastic background were published for all observing runs of the LIGOVirgo detectors. However, a broadband analysis is likely to miss narrowband signals as the signaltonoise ratio of a narrowband signal can be significantly reduced when combined with detector output from other frequencies. Data folding and the computationally efficient analysis pipeline, PyStoch, enable us to perform the radiometer mapmaking at every frequency bin. We perform the search at 3072 HEALPix equal area pixels uniformly tiling the sky and in every frequency bin of width 1 /32 Hz in the range 201726 Hz, except for bins that are likely to contain instrumental artefacts and hence are notched. We do not find any statistically significant evidence for the existence of narrowband gravitationalwave signals in the analyzed frequency bins. Therefore, we place 95% confidence upper limits on the gravitationalwave strain for each pixelfrequency pair, the limits are in the range (0.030 9.6 )×10^{24}. In addition, we outline a method to identify candidate pixelfrequency pairs that could be followed up by a more sensitive (and potentially computationally expensive) search, e.g., a matchedfilteringbased analysis, to look for fainter nearly monochromatic coherent signals. The ASAF analysis is inherently independent of models describing any spectral or spatial distribution of power. We demonstrate that the ASAF results can be appropriately combined over frequencies and sky directions to successfully recover the broadband directional and isotropic results.
 Publication:

Physical Review D
 Pub Date:
 June 2022
 DOI:
 10.1103/PhysRevD.105.122001
 arXiv:
 arXiv:2110.09834
 Bibcode:
 2022PhRvD.105l2001A
 Keywords:

 General Relativity and Quantum Cosmology
 EPrint:
 22 pages, 6 figures, 1 table