Directed search for continuous gravitational-wave signals from the Galactic Center in the Advanced LIGO second observing run

Abstract

In this work we present the results of a search for continuous gravitational waves from the Galactic Center using LIGO O2 data. The search uses the Band-Sampled-Data directed search pipeline, which performs a semi-coherent wide-parameter-space search, exploiting the robustness of the Frequency-Hough transform algorithm. The search targets signals emitted by isolated asymmetric spinning neutron stars, located within the few inner parsecs of the Galactic Center. The frequencies covered in this search range between 10 Hz and 710 Hz with a spin-down range from −1.8 × 10 −9 Hz/s to 3.7 × 10 −11 Hz/s. No continuous wave signal has been detected and upper limits on the gravitational wave amplitude are presented. The most stringent upper limit at 95% confidence level, for Livingston detector, is ∼ 1.4 × 10 −25 at 163 Hz. To date, this is the most sensitive directed search for continuous gravitational-wave signals from the Galactic Center and the first search of this kind using LIGO second observing run.

Directed searches for continuous gravitational waves from twelve supernova remnants in data from Advanced LIGO’s second observing run

“…Most searches targeted relatively young SNRs [3][4][5][6][7][8][9][10][11]. Some searches targeted promising small areas such as the galactic center [4,8,[11][12][13]. One search targeted a nearby globular cluster, where multi-body interactions might effectively rejuvenate an old neutron star for purposes of continuous GW emission [14].…”

Science case for the Einstein telescope

“…No continuous gravitational wave signal has so far been observed by Advanced LIGO and Advanced Virgo, see e.g. [46][47][48][49][50][51] for recently obtained upper limits. The detection of continuous GWs from NS by ET would be a fundamental breakthrough, that would provide clues about the condition of formation of isolated NS, their spin, thermal evolution and magnetic field.…”

Results from an Einstein@Home search for continuous gravitational waves from Cassiopeia A, Vela Jr., and G347.3

“…In-between, the directed searches target locations in the sky that are known or suspected to harbour a neutron star, albeit pulsation shave generally not been observed. Searches of this type include the galactic centre (Piccinni et al 2020;Dergachev et al 2019), young supernova remnants (SNRs) (Ming et al 2019;Papa et al 2020;Abbott et al 2019c;Millhouse et al 2020;Lindblom & Owen 2020;Abbott et al 2021d), glitching pulsars (Fesik & Papa 2020;Abbott et al 2021e) and low-mass X-ray binaries such as Scorpius X-1 (Zhang et al 2021).…”