A possible precursor for the detection of nanohertz gravitational waves or unmodeled pulsar noise?
Compact binary coalescence (CBC)
Gravitational wave strain and model parameters
Fourier-transformed gravitational wave strain :
Where M is a chirp mass, DL is a luminosity distance, A is the amplitude, Psi is the phase, and C is a geometric detector parameter. The amplitude and the phase are represented as post-Newtonian expansion series.
To the zero'th order,
Gravitational wave frequency evolution in time
Two neutron stars or black holes in a close binary system emit gravitational radiation and get closer and closer together, until they merge. Gravitational wave frequency evolves as a function of time and chirp mass :
Continuous gravitational wave (CW)
Diffraction limited resolution
Sky resolution of laser interferometers (LIGO, Virgo, Kagra, etc.) depends on a gravitational wave frequency as :
Fourier segment duration and loss of SNR
Selecting long segment durations in gravitational wave data analysis for terrestrial-based detectors leads to a higher frequency-domain resolution. However, at the same time, it may lead to a loss of SNR at high frequencies due to sidereal rotation of the Earth with respect to a gravitational wave source. If we can accept only SNR losses of 10% or less, we should constrain the Fourier segment duration by :
- LIGO Scientific and VIRGO Collaborations, et al. "The basic physics of the binary black hole merger GW150914." Annalen der Physik 529.1-2 (2017): 1600209.
- Goncharov, B., Thrane, E., 2018. All-sky radiometer for narrowband gravitational waves using folded data. Physical Review D, 98(6), p.064018.
- Thrane, E., Mandic, V. and Christensen, N., 2015. Detecting very long-lived gravitational-wave transients lasting hours to weeks. Physical Review D, 91(10), p.104021.
- Cutler, C., & Flanagan, E. E. (1994). Gravitational waves from merging compact binaries: How accurately can one extract the binary’s parameters from the inspiral waveform?. Physical Review D, 49(6), 2658.
We model red noise and link exponential dips in residuals with pulse shape changes