2004/03/10 by Naoki Seto, Asantha Cooray · 1 citation
Physics and Astronomy · #Advanced Frequency and Time Standards #Astrophysics #Binary number #Computational physics #Gravitational wave #Harmonic #Measure (data warehouse) #Physics #Population #Pulsars and Gravitational Waves Research #Quadrupole #Quantum mechanics #Spherical harmonics #Stellar, planetary, and galactic studies #astro-ph #gr-qc
paper · pdf · doi:10.1103/physrevd.70.123005
published as Phys.Rev. D70 (2004) 123005 · 8 pages, 2 figures
arxiv created 2004/03/10 · openalex publication_date 2004/12/09 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We discuss spatial fluctuations in the gravitational wave background arising from unresolved Galactic binary sources, such as close white dwarf binaries, due to the fact the galactic binary source distribution is anisotropic. We introduce a correlation analysis of the two data streams of the Laser Interferometer Space Antenna (LISA) to extract spherical harmonic coefficients of the hexadecapole moment (l=4) related to the projected two-dimensional density distribution of the binary source population in an independent manner. In this analysis, we use a free parameter with which we can effectively control the frequency of the cartwheel rotation of LISA. The proposed technique complements and improves over previous suggestions in the literature to measure the gravitational wave background anisotropy based on the time modulation of data as LISA orbits around the Sun. Such techniques, however, are restricted only to certain combinations of spherical harmonic coefficients of the galaxy with no ability to separate them individually. With LISA, m=2,3 and 4 coefficients of the hexadecapole (l=4) can be measured with signal-to-noise ratios at the level of ten and above in a certain coordinate system. In addition to the hexadecapole coefficients, when combined with the time modulation analysis, the correlation study also can be used, in principle, to measure quadrupole coefficients of the binary distribution.