We present the first directed searches for long-transient and continuous gravitational waves from ultralight vector boson clouds around known black holes (BHs). We use LIGO data from the first part of the fourth LIGO-Virgo-KAGRA observing run. The searches target two distinct types of BHs and use two new semicoherent methods: hidden Markov model (HMM) tracking for the remnant BHs of the mergers GW230814\_230901 and GW231123\_135430 (referred to as GW230814 and GW231123 in this study), and a dedicated method using the Band Sampled Data (BSD) framework for the galactic BH in the Cygnus X-1 binary system. Without finding evidence of a signal from vector bosons in the data, we estimate the mass range that can be constrained. For the HMM searches targeting the remnants from GW231123 and GW230814, we disfavor vector boson masses in the ranges \$[0.94, 1.08]\$ and \$[2.75, 3.28] \textbackslash{}times 10\textasciicircum{}\{-13\}\$ eV, respectively, at 30\% confidence, assuming a 1\% false alarm probability. Although these searches are only marginally sensitive to signals from merger remnants at relatively large distances, future observations are expected to yield more stringent constraints with high confidence. For the BSD search targeting the BH in Cygnus X-1, we exclude vector boson masses in the range \$[0.85, 1.59] \textbackslash{}times 10\textasciicircum{}\{-13\}\$ eV at 95\% confidence, assuming an initial BH spin larger than 0.5.
LIGO Scientific, Virgo, KAGRA Collaborations 2026, 'Directed searches for gravitational waves from ultralight vector boson clouds around merger remnant and galactic black holes during the first part of the fourth LIGO-Virgo-KAGRA observing run', Physical Review D. https://doi.org/10.1103/mjfs-m6t7
LIGO Scientific, Virgo, KAGRA Collaborations (2026). Directed searches for gravitational waves from ultralight vector boson clouds around merger remnant and galactic black holes during the first part of the fourth LIGO-Virgo-KAGRA observing run. Physical Review D. https://doi.org/10.1103/mjfs-m6t7
@article{433c67f81c954108ac7ef2fd6fd10d7c,
title = "Directed searches for gravitational waves from ultralight vector boson clouds around merger remnant and galactic black holes during the first part of the fourth LIGO-Virgo-KAGRA observing run",
abstract = "We present the first directed searches for long-transient and continuous gravitational waves from ultralight vector boson clouds around known black holes (BHs). We use LIGO data from the first part of the fourth LIGO-Virgo-KAGRA observing run. The searches target two distinct types of BHs and use two new semicoherent methods: hidden Markov model (HMM) tracking for the remnant BHs of the mergers GW230814\_230901 and GW231123\_135430 (referred to as GW230814 and GW231123 in this study), and a dedicated method using the Band Sampled Data (BSD) framework for the galactic BH in the Cygnus X-1 binary system. Without finding evidence of a signal from vector bosons in the data, we estimate the mass range that can be constrained. For the HMM searches targeting the remnants from GW231123 and GW230814, we disfavor vector boson masses in the ranges \$[0.94, 1.08]\$ and \$[2.75, 3.28] \textbackslash{}times 10\textasciicircum{}\{-13\}\$ eV, respectively, at 30\% confidence, assuming a 1\% false alarm probability. Although these searches are only marginally sensitive to signals from merger remnants at relatively large distances, future observations are expected to yield more stringent constraints with high confidence. For the BSD search targeting the BH in Cygnus X-1, we exclude vector boson masses in the range \$[0.85, 1.59] \textbackslash{}times 10\textasciicircum{}\{-13\}\$ eV at 95\% confidence, assuming an initial BH spin larger than 0.5.",
keywords = "gr-qc, astro-ph.HE, hep-ph",
author = "\{LIGO Scientific, Virgo, KAGRA Collaborations\} and D. Adhikari and Adhikari, \{R. X.\} and W. Ali and G. Baldi and Bell, \{A. S.\} and Blair, \{C. D.\} and S. Bose and H. Cao and S. Chakraborty and Chan, \{J. C. L.\} and D. Chen and H. Chen and H. Chen and S. Chen and C. Chou and N. Christensen and Clark, \{J. A.\} and Collette, \{C. G.\} and A. Colombo and L. Conti and Cullen, \{T. J.\} and Davis, \{M. C.\} and P. Davis and Bolle, \{J. De\} and D{\'i}az, \{M. C.\} and J. Ding and H. Duval and M. Esposito and M. Gosselin and J. Graves and H. Guo and W. Guo and Y. Guo and Gupta, \{N. C.\} and Gupta, \{S. K.\} and N. Gutierrez and Huang, \{H. Y.\} and Y. Huang and Y. Huang and Iqbal, \{M. H.\} and M. Jain and T. Jain and James, \{A. L.\} and M. Jensen and J. Jiang and Jin, \{H. -B.\} and Jones, \{D. I.\} and Jones, \{D. I.\} and Joshi, \{S. K.\} and Kim, \{J. C.\} and Kim, \{M. H.\} and S. Kim and Kim, \{Y. -M.\} and M. Lalleman and J. Larsen and Lee, \{H. W.\} and Lee, \{H. W.\} and J. Lee and K. Lee and Y. Lee and Li, \{A. K. Y.\} and Li, \{K. L.\} and Li, \{T. G. F.\} and X. Li and Y. Li and Z. Li and Lin, \{Y. -C.\} and Liu, \{G. C.\} and Jian Liu and A. Malik and M. Mantovani and Martin, \{R. M.\} and Martins, \{J. C.\} and C. Michel and Miller, \{S. J.\} and Mitchell, \{A. L.\} and S. More and S. Ng and A. Pal and S. Pal and H. Pan and A. Parisi and S. Peters and H. Pham and M. Pinto and Pradhan, \{B. K.\} and J. Qin and S. Raja and R. Reyes and M. Ricci and Richardson, \{J. W.\} and Richardson, \{M. L.\} and Roy, \{S. K.\} and Roy, \{S. K.\} and S. Saha and M. Sakellariadou and A. Sanchez and Sanchez, \{E. J.\} and Sanchez, \{L. E.\} and Sanders, \{J. R.\} and P. Schmidt and Sengupta, \{A. S.\} and A. Sevrin and Shaikh, \{M. A.\} and N. Singh and S. Singh and L. Smith and Smith, \{R. J. E.\} and I. Song and V. Sordini and P. Stevens and J. Sun and L. Sun and K. Tanaka and Tanaka, \{S. J.\} and Thomas, \{L. M.\} and M. Thomas and P. Thomas and K. Tran and K. Turbang and \{van Dael\}, M. and \{den Bossche\}, \{E. Van\} and Broeck, \{C. Van Den\} and \{de Walle\}, \{A. Van\} and \{van Dongen\}, J. and M. Vereecken and Vermeulen, \{S. M.\} and Vincent, \{E. T.\} and Wang, \{E. J.\} and H. Wang and Wang, \{J. Z.\} and Wang, \{W. H.\} and Wang, \{Y. F.\} and Williams, \{M. J.\} and M. Wils and Wong, \{H. T.\} and T. Wouters and Wright, \{J. L.\} and C. Wu and Wu, \{D. S.\} and H. Wu and K. Wu and Q. Wu and Y. Wu and Z. Wu and Y. Xu and N. Yadav and Y. Yang and M. Zeeshan and L. Zhang and T. Zhang and C. Zhao and Zhao, \{Z. -C.\} and Y. Zheng and Zhu, \{H. O.\}",
note = "34 pages, 4 figures",
year = "2026",
month = jul,
day = "28",
doi = "10.1103/mjfs-m6t7",
language = "English",
journal = "Physical Review D",
issn = "2470-0010",
publisher = "American Physical Society",
}