We report on an all-sky search for periodic gravitational waves in the frequency band 20-475 Hz and with a frequency time derivative in the range of [-1.0,+0.1]×10-8 Hz/s. Such a signal could be produced by a nearby spinning and slightly nonaxisymmetric isolated neutron star in our galaxy. This search uses the data from Advanced LIGO's first observational run, O1. No periodic gravitational wave signals were observed, and upper limits were placed on their strengths. The lowest upper limits on worst-case (linearly polarized) strain amplitude h0 are ∼4×10-25 near 170 Hz. For a circularly polarized source (most favorable orientation), the smallest upper limits obtained are ∼1.5×10-25. These upper limits refer to all sky locations and the entire range of frequency derivative values. For a population-averaged ensemble of sky locations and stellar orientations, the lowest upper limits obtained for the strain amplitude are ∼2.5×10-25. © 2017 American Physical Society.

Chandra Kant Mishra

Department Of Physics

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IIT Madras

Physical Review D

One unanswered question about the binary neutron star coalescence GW170817 is the nature of its post-merger remnant. A previous search for post-merger gravitational waves targeted high-frequency signals from a possible neutron star remnant with a maximum signal duration of 500 s. Here, we revisit the neutron star remnant scenario and focus on longer signal durations, up until the end of the second Advanced LIGO-Virgo observing run, which was 8.5 days after the coalescence of GW170817. The main physical scenario for this emission is the power-law spindown of a massive magnetar-like remnant. We use four independent search algorithms with varying degrees of restrictiveness on the signal waveform and different ways of dealing with noise artefacts. In agreement with theoretical estimates, we find no significant signal candidates. Through simulated signals, we quantify that with the current detector sensitivity, nowhere in the studied parameter space are we sensitive to a signal from more than 1 Mpc away, compared to the actual distance of 40 Mpc. However, this study serves as a prototype for post-merger analyses in future observing runs with expected higher sensitivity. © 2019. The American Astronomical Society. All rights reserved..

Astrophysical Journal

Search for Gravitational Waves from a Long-lived Remnant of the Binary Neutron Star Merger GW170817

All-sky search for periodic gravitational waves in the O1 LIGO data

Search for continuous gravitational waves from neutron stars in globular cluster NGC 6544

Validating gravitational-wave detections: The Advanced LIGO hardware injection system

Physical Review Letters

Upper Limits on the Stochastic Gravitational-Wave Background from Advanced LIGO’s First Observing Run

Hierarchical follow-up of subthreshold candidates of an all-sky Einstein@Home search for continuous gravitational waves on LIGO sixth science run data

Journal	Data powered by TypesetPhysical Review D
Publisher	Data powered by TypesetAmerican Physical Society
ISSN	24700010
Open Access	Yes