T. Sadecki

TL;DR: In this article, a semicoherent search for continuous gravitational waves from the low-mass X-ray binary Scorpius X-1, using data from the first Advanced LIGO observing run, was conducted over the frequency range 25-2000\,\mathrm{Hz}, spanning the current observationally constrained range of binary orbital parameters.

TL;DR: In this article, a new all-sky search for periodic gravitational waves in the frequency band 475-2000 Hz and with a frequency time derivative in the range of [-1.0,+0.1]×10-8 Hz/s was reported.

TL;DR: In this paper, the authors presented results from a semicoherent search for continuous gravitational waves from the low-mass X-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering.

Abstract: We perform an unmodeled search for persistent, directional gravitational wave (GW) sources using data from the first and second observing runs of Advanced LIGO. We do not find evidence for any GW signals. We place limits on the broadband GW flux emitted at 25 Hz from point sources with a power law spectrum at Fα,Θ<(0.05–25)×10−8 erg cm−2 s−1 Hz−1 and the (normalized) energy density spectrum in GWs at 25 Hz from extended sources at Ωα(Θ)<(0.19–2.89)×10−8 sr−1 where α is the spectral index of the energy density spectrum. These represent improvements of 2.5–3× over previous limits. We also consider point sources emitting GWs at a single frequency, targeting the directions of Sco X-1, SN 1987A, and the Galactic center. The best upper limits on the strain amplitude of a potential source in these three directions range from h0<(3.6–4.7)×10−25, 1.5× better than previous limits set with the same analysis method. We also report on a marginally significant outlier at 36.06 Hz. This outlier is not consistent with a persistent gravitational-wave source as its significance diminishes when combining all of the available data.

TL;DR: In this paper, the authors summarize past electromagnetic follow-up efforts as well as the organization and policy of the current EM followup program and compare the four probability sky maps produced for the gravitational-wave transient GW150914, and provide additional details of the EM follow up observations that were performed in the different bands.