TY - JOUR
T1 - Analysis of a subsolar-mass compact binary candidate from the second observing run of Advanced LIGO
AU - Morrás, Gonzalo
AU - Nuño Siles, José Francisco
AU - García-Bellido, Juan
AU - Ruiz Morales, Ester
AU - Menéndez-Vázquez, Alexis
AU - Karathanasis, Christos
AU - Martinovic, Katarina
AU - Phukon, Khun Sang
AU - Clesse, Sebastien
AU - Martínez, Mario
AU - Sakellariadou, Mairi
PY - 2023/12
Y1 - 2023/12
N2 - We perform an exhaustive follow-up analysis of a subsolar-mass (SSM) gravitational wave (GW) candidate reported by Phukon et al. from the second observing run of Advanced LIGO. This candidate has a reported signal-to-noise ratio (SNR) of 8.6 and false alarm rate of 0.41 yr which are too low to claim a clear gravitational-wave origin. When improving on the search by using more accurate waveforms, extending the frequency range from 45 Hz down to 20 Hz, and removing a prominent blip glitch, we find that the posterior distribution of the network SNR lies mostly below the search value, with the 90% confidence interval being 7 . 9 4 − 1 . 05 + 0 . 70 . Assuming that the origin of the signal is a compact binary coalescence (CBC), the secondary component is m 2 = 0 . 7 6 − 0 . 14 + 0 . 50 M ⊙ , with m 2 < 1 M ⊙ at 84 % confidence level, suggesting an unexpectedly light neutron star or a black hole of primordial or exotic origin. The primary mass would be m 1 = 4 . 7 1 − 2 . 18 + 1 . 57 M ⊙ , likely in the hypothesized lower mass gap and the luminosity distance is measured to be D L = 12 4 − 48 + 82 Mpc. We then probe the CBC origin hypothesis by performing the signal coherence tests, obtaining a log Bayes factor of 4 . 96 ± 0 . 13 for the coherent vs. incoherent hypothesis. We demonstrate the capability of performing a parameter estimation follow-up on real data for an SSM candidate with moderate SNR. The improved sensitivity of O4 and subsequent LIGO-Virgo-KAGRA observing runs could make it possible to observe similar signals, if present, with a higher SNR and more precise measurement of the parameters of the binary.
AB - We perform an exhaustive follow-up analysis of a subsolar-mass (SSM) gravitational wave (GW) candidate reported by Phukon et al. from the second observing run of Advanced LIGO. This candidate has a reported signal-to-noise ratio (SNR) of 8.6 and false alarm rate of 0.41 yr which are too low to claim a clear gravitational-wave origin. When improving on the search by using more accurate waveforms, extending the frequency range from 45 Hz down to 20 Hz, and removing a prominent blip glitch, we find that the posterior distribution of the network SNR lies mostly below the search value, with the 90% confidence interval being 7 . 9 4 − 1 . 05 + 0 . 70 . Assuming that the origin of the signal is a compact binary coalescence (CBC), the secondary component is m 2 = 0 . 7 6 − 0 . 14 + 0 . 50 M ⊙ , with m 2 < 1 M ⊙ at 84 % confidence level, suggesting an unexpectedly light neutron star or a black hole of primordial or exotic origin. The primary mass would be m 1 = 4 . 7 1 − 2 . 18 + 1 . 57 M ⊙ , likely in the hypothesized lower mass gap and the luminosity distance is measured to be D L = 12 4 − 48 + 82 Mpc. We then probe the CBC origin hypothesis by performing the signal coherence tests, obtaining a log Bayes factor of 4 . 96 ± 0 . 13 for the coherent vs. incoherent hypothesis. We demonstrate the capability of performing a parameter estimation follow-up on real data for an SSM candidate with moderate SNR. The improved sensitivity of O4 and subsequent LIGO-Virgo-KAGRA observing runs could make it possible to observe similar signals, if present, with a higher SNR and more precise measurement of the parameters of the binary.
U2 - 10.1016/j.dark.2023.101285
DO - 10.1016/j.dark.2023.101285
M3 - Article
SN - 2212-6864
VL - 42
JO - Physics of the Dark Universe
JF - Physics of the Dark Universe
M1 - 101285
ER -