Prospects for detecting gravitational waves at 5 Hz with ground-based detectors

• Published in: arXiv.org 2018-04
• Main Authors: Yu, Hang, Martynov, Denis, Vitale, Salvatore, Evans, Matthew, Barr, Bryan, Carbone, Ludovico, Dooley, Katherine L, Freise, Andreas, Fulda, Paul, Grote, Hartmut, Hammond, Giles, Hild, Stefan, Hough, James, Huttner, Sabina, Mow-Lowry, Conor, Rowan, Sheila, Shoemaker, David, Sigg, Daniel, Sorazu, Borja
• Format: Article
• Language: English
• Subjects: Binary stars; Black holes; Coalescing; Detectors; Gravitational effects; Gravitational waves; Low frequencies; Neutron stars; Neutrons; Red shift; Seismographs
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1712.05417

We propose an upgrade to Advanced LIGO (aLIGO), named LIGO-LF, that focuses on improving the sensitivity in the 5-30 Hz low-frequency band, and we explore the upgrade's astrophysical applications. We present a comprehensive study of the detector's technical noises and show that with technologies currently under development, such as interferometrically sensed seismometers and balanced-homodyne readout, LIGO-LF can reach the fundamental limits set by quantum and thermal noises down to 5 Hz. These technologies are also directly applicable to the future generation of detectors. We go on to consider this upgrade's implications for the astrophysical output of an aLIGO-like detector. A single LIGO-LF can detect mergers of stellar-mass black holes (BHs) out to a redshift of z~6 and would be sensitive to intermediate-mass black holes up to 2000 M_\odot. The detection rate of merging BHs will increase by a factor of 18 compared to aLIGO. Additionally, for a given source the chirp mass and total mass can be constrained 2 times better than aLIGO and the effective spin 3-5 times better than aLIGO. Furthermore, LIGO-LF enables the localization of coalescing binary neutron stars with an uncertainty solid angle 10 times smaller than that of aLIGO at 30 Hz, and 4 times smaller when the entire signal is used. LIGO-LF also significantly enhances the probability of detecting other astrophysical phenomena including the tidal excitation of neutron star r-modes and the gravitational memory effects.