Localization and broadband follow-up of the gravitational-wave transient GW150914

A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground- and space-based facilities. In this Letter we describe the low-latency analysis of the GW data and present the sky localization of the first observed compact binary merger. We summarize the follow-up observations reported by 25 teams via private Gamma-ray Coordinates Network circulars, giving an overview of the participating facilities, the GW sky localization coverage, the timeline, and depth of the observations. As this event turned out to be a binary black hole merger, there is little expectation of a detectable electromagnetic (EM) signature. Nevertheless, this first broadband campaign to search for a counterpart of an Advanced LIGO source represents a milestone and highlights the broad capabilities of the transient astronomy community and the observing strategies that have been developed to pursue neutron star binary merger events. Detailed investigations of the EM data and results of the EM follow-up campaign are being disseminated in papers by the individual teams

Localization and broadband follow-up of the gravitational-wave transient GW150914

A gravitational-wave transient was identified in data recorded by the Advanced LIGO detectors on 2015 September 14. The event candidate, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground- and space-based facilities. In this Letter we describe the low-latency analysis of the gravitational wave data and present the sky localization of the first observed compact binary merger. We summarize the follow-up observations reported by 25 teams via private Gamma-ray Coordinates Network Circulars, giving an overview of the participating facilities, the gravitational wave sky localization coverage, the timeline and depth of the observations. As this event turned out to be a binary black hole merger, there is little expectation of a detectable electromagnetic signature. Nevertheless, this first broadband campaign to search for a counterpart of an Advanced LIGO source represents a milestone and highlights the broad capabilities of the transient astronomy community and the observing strategies that have been developed to pursue neutron star binary merger events. Detailed investigations of the electromagnetic data and results of the electromagnetic follow-up campaign will be disseminated in the papers of the individual teams

Nonsense Made Intelligible

My topic is the relation between nonsense and (un-)intelligibility, and the contrast between nonsense and falsehood which played a pivotal role in the rise of analytic philosophy (sct. 1). I shall pursue three lines of inquiry. First I shall briefly consider the positive case, namely linguistic understanding (sct. 2). Secondly, I shall consider the negative case—different breakdowns of understanding and connected forms of failure to make sense (sct. 3–4). Third, I shall criticize three important misconceptions of nonsense and unintelligibility: the austere conception of nonsense propounded by the New Wittgensteinians (scts. 5–6); the “no nonsense position” which roundly denies that there are cases of nonsense—Chomsky’s semantic anomalies or Ryle’s category mistakes–that are grammatically well-formed, without even having the potential for being used to make a truth-apt statement (scts. 7–8); the individualistic conception of language and of semantic mistakes championed by Davidson (scts. 9–10). All three positions, I shall argue, ignore or deny combinatorial nonsense, the fact that perfectly meaningful sentence-components can be combined in a way that may be grammatical, yet without resulting in a sentence that is itself “meaningful”, i.e. endowed with linguistic sense. At a more strategic level, the first and the third position deny or ignore that natural languages are communal historical practices that go beyond idiolects and the employments of expressions in specific contexts and that are guided by semantic rules—standards for the meaningful use of words