Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model

• Published in: arXiv.org 2019-11
• Main Authors: Ananyeva, A, Areeda, J S, Arnaud, N, Aston, S M, Barayoga, J C, Barta, D, Bernuzzi, S, Bode, N, Bossilkov, V, Bosveld, J, Bouffanais, Y, Brinkmann, M, Calloni, E, Cerretani, G, Chao, S, Chia, H Y, Cho, M, Cleva, F, Cocchieri, C, Costa, C A, Daw, E J, Degallaix, J, Deléglise, S, Dent, T, Díaz, M C, Dietrich, T, Estelles, H, Fairhurst, S, Favata, M, Fidecaro, F, Fyffe, M, Gair, J R, Giazotto, A, Goncharov, B, Gruning, P, Hall, B R, Hannuksela, O A, Heidmann, A, Heptonstall, A W, Hoy, C G, Hulko, M, Iyer, B R, Kang, G, Karki, S, Keerthana, N V, Kijbunchoo, N, Kim, W, Klika, J H, Koehlenbeck, S M, Kumar, P, Landry, M, Lazzarini, A, Lecoeuche, Y K, Y Ma, Malik, A, Mandic, V, Maros, E, Martelli, F, Mason, K, Mukherjee, Arunava, Obergaulinger, M, O'Brien, B D, Okada, M A, O'Reilly, B, Pele, A, Penn, S, Pitkin, M, Poggiani, R, Prasad, J, Privitera, S, Punturo, M, Rajan, C, Reitze, D H, Ricci, F, Rolland, L, Rose, K, Saleem, M, Sanchez, E J, Sanders, J R, Schale, P, Scheuer, J, Shaffer, T, Siellez, K, Singer, L P, Steinmeyer, D, Sudhir, V, Szczepańczyk, M J, Thomas, M, Töyrä, D, Trovato, A, van Heijningen, J V, Wade, A R, Wang, Y F, Ward, R L, Weaver, B, Wright, J L, Yeeles, D W, Zhang, J, Zucker, M E, Dunn, L M
• Format: Article
• Language: English
• Subjects: Confidence; Data search; Frequency ranges; Gravitation; Gravitational waves; Inclination angle; Markov analysis; Markov chains; Matched filters; X ray binaries; X ray stars
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1906.12040

We present results from a semicoherent search for continuous gravitational waves from the low-mass X-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the \(\mathcal{J}\)-statistic, and by analysing data from Advanced LIGO's second observing run. In the frequency range searched, from \(60\) to \(650\,\mathrm{Hz}\), we find no evidence of gravitational radiation. At \(194.6\,\mathrm{Hz}\), the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95\% confidence) of \(h_0^{95\%} = 3.47 \times 10^{-25}\) when marginalising over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering.