Abstract Details

Name: Shasvath Kapadia
Affiliation: International Centre for Theoretical Sciences
Conference ID: ASI2021_91
Title : Of Harbingers and Higher Modes: Improved gravitational-wave early-warning of compact binary mergers
Authors and Co-Authors : Shasvath J. Kapadia (ICTS-TIFR) Mukesh Kumar Singh (ICTS-TIFR) Md Arif Shaikh (ICTS-TIFR) Deep Chatterjee (University of Illinois Urbana Champaign) Parameswaran Ajith (ICTS-TIFR)
Abstract Type : Oral
Abstract Category : Extragalactic Astronomy
Abstract : A crucial component to maximizing the science gain from the multi-messenger follow-up of gravitational-wave (GW) signals from compact binary mergers is the prompt discovery of the electromagnetic counterpart. Ideally, the GW detection and localization must be reported early enough to allow for telescopes to slew to the location of the GW-event before the onset of the counterpart. However, the time available for early warning is limited by the short duration spent by the dominant (ℓ=m=2) mode within the detector's frequency band. Nevertheless, we show that, including higher modes - which enter the detector's sensitivity band well before the dominant mode - in GW searches, can enable us to significantly improve the early warning ability for compact binaries with asymmetric masses (such as neutron-star-black-hole binaries). We investigate the reduction in the localization sky-area when the ℓ=m=3 and ℓ=m=4 modes are included in addition to the dominant mode, considering typical slew-times of electromagnetic telescopes (30−60 sec). We find that, in LIGO's projected "O5" ("Voyager") network with five GW detectors, some of the neutron-star-black-hole mergers, located at a distance of 40 Mpc, can be localized to a few hundred sq. deg. ∼45 sec prior to the merger, corresponding to a reduction-factor of 3−4 (5−6) in sky-area. For a third-generation network, we get gains of up to 1.5 minutes in early warning times for a localization area of 100 sq. deg., even when the source is placed at 100 Mpc.