Detecting binary compact-object mergers with gravitational waves: Understanding and Improving the sensitivity of the PyCBC search

We present an improved search for binary compact-object mergers using a network of ground-based gravitational-wave detectors. We model a volumetric, isotropic source population and incorporate the resulting distribution over signal amplitude, time delay, and coalescence phase into the ranking of candidate events. We describe an improved modeling of the background distribution, and demonstrate incorporating a prior model of the binary mass distribution in the ranking of candidate events. We find a $\sim 10\%$ and $\sim 20\%$ increase in detection volume for simulated binary neutron star and neutron star--binary black hole systems, respectively, corresponding to a reduction of the false alarm rates assigned to signals by between one and two orders of magnitude.Comment: 7 pages, 3 figures, as accepted by Ap

Significance of arming, potentiating and blocking factors as correlates the tumour-host interaction in the hamster SV40 system.

The study of blocking factors requires in vitro assay of cell mediated immunity that parallels the in vivo response. By microcytotoxicity testing, progressor and immune peripheral blood lymphocytes caused significant target cell reduction. The cytotoxicity was specific as no cytotoxic effect was detected against unrelated normal as well as a malignant target cell lines. No anti-tumour effect was noted when progressor peripheral blood lymphocytes were evaluated in the Winn assay. In marked contrast, immune peripheral blood lymphocytes were capable of preventing tumour growth in the Winn assay. Furthermore, hamsters repeatedly immunized with irradiated SV40 tumour cells could resist a live cell challenge. Thus immune peripheral blood lymphocytes were chosen as the effector population to evaluate the abrogation ability of serum in the microcytotoxicity assay

A Time Variation of Proton-Electron Mass Ratio and Grand Unification

Astrophysical observations indicate a time variation of the proton-electron mass ratio and of the fine-structure constant. We discuss this phenomenon in models of Grand Unification. In these models a time variation of the fine-structure constant and of the proton mass are expected, if either the unified coupling constant or the scale of unification changes, or both change. We discuss in particular the change of the proton mass. Experiments in Quantum Optics could be done to check these ideas.Comment: 5 page

Low significance of evidence for black hole echoes in gravitational wave data

Recent detections of merging black holes allow observational tests of the nature of these objects. In some proposed models, non-trivial structure at or near the black hole horizon could lead to echo signals in gravitational wave data. Recently, Abedi et al. claimed tentative evidence for repeating damped echo signals following the gravitational-wave signals of the binary black hole merger events recorded in the first observational period of the Advanced LIGO interferometers. We reanalyse the same data, addressing some of the shortcomings of their method using more background data and a modified procedure. We find a reduced statistical significance for the claims of evidence for echoes, calculating increased p-values for the null hypothesis of echo-free noise. The reduced significance is entirely consistent with noise, and so we conclude that the analysis of Abedi et al. does not provide any observational evidence for the existence of Planck-scale structure at black hole horizons.Comment: As accepted by Physical Review

Investigation of the fundamental constants stability based on the reactor Oklo burn-up analysis

The burn-up for SC56-1472 sample of the natural Oklo reactor zone 3 was calculated using the modern Monte Carlo codes. We reconstructed the neutron spectrum in the core by means of the isotope ratios: $^{147}$Sm/$^{148}$Sm and $^{176}$Lu/$^{175}$Lu. These ratios unambiguously determine the spectrum index and core temperature. The effective neutron absorption cross section of $^{149}$Sm calculated using this spectrum was compared with experimental one. The disagreement between these two values allows to limit a possible shift of the low laying resonance of $^{149}$Sm even more . Then, these limits were converted to the limits for the change of the fine structure constant $\alpha$. We found that for the rate of $\alpha$ change the inequality $|\delta \dot{\alpha}/\alpha| \le 5\cdot 10^{-18}$ is fulfilled, which is of the next higher order than our previous limit.Comment: 16 pages, 7 figure

The JCMT 12CO(3-2) Survey of the Cygnus X Region: I. A Pathfinder

Cygnus X is one of the most complex areas in the sky. This complicates interpretation, but also creates the opportunity to investigate accretion into molecular clouds and many subsequent stages of star formation, all within one small field of view. Understanding large complexes like Cygnus X is the key to understanding the dominant role that massive star complexes play in galaxies across the Universe. The main goal of this study is to establish feasibility of a high-resolution CO survey of the entire Cygnus X region by observing part of it as a Pathfinder, and to evaluate the survey as a tool for investigating the star-formation process. A 2x4 degree area of the Cygnus X region has been mapped in the 12CO(3-2) line at an angular resolution of 15" and a velocity resolution of ~0.4km/s using HARP-B and ACSIS on the James Clerk Maxwell Telescope. The star formation process is heavily connected to the life-cycle of the molecular material in the interstellar medium. The high critical density of the 12CO(3-2) transition reveals clouds in key stages of molecule formation, and shows processes that turn a molecular cloud into a star. We observed ~15% of Cygnus X, and demonstrated that a full survey would be feasible and rewarding. We detected three distinct layers of 12CO(3-2) emission, related to the Cygnus Rift (500-800 pc), to W75N (1-1.8 kpc), and to DR21 (1.5-2.5 kpc). Within the Cygnus Rift, HI self-absorption features are tightly correlated with faint diffuse CO emission, while HISA features in the DR21 layer are mostly unrelated to any CO emission. 47 molecular outflows were detected in the Pathfinder, 27 of them previously unknown. Sequentially triggered star formation is a widespread phenomenon.Comment: 18 pages, 13 figures, accepted for publication in Astronomy & Astrophysic

Paracrine IL-2 Is Required for Optimal Type 2 Effector Cytokine Production

IL-2 is a pleiotropic cytokine that promotes the differentiation of Th cell subsets, including Th1, Th2, and Th9 cells, but it impairs the development of Th17 and T follicular helper cells. Although IL-2 is produced by all polarized Th subsets to some level, how it impacts cytokine production when effector T cells are restimulated is unknown. We show in this article that Golgi transport inhibitors (GTIs) blocked IL-9 production. Mechanistically, GTIs blocked secretion of IL-2 that normally feeds back in a paracrine manner to promote STAT5 activation and IL-9 production. IL-2 feedback had no effect on Th1- or Th17-signature cytokine production, but it promoted Th2- and Th9-associated cytokine expression. These data suggest that the use of GTIs results in an underestimation of the presence of type 2 cytokine-secreting cells and highlight IL-2 as a critical component in optimal cytokine production by Th2 and Th9 cells in vitro and in vivo

Slow roll inflation in the presence of a dark energy coupling

In models of coupled dark energy, in which a dark energy scalar field couples to other matter components, it is natural to expect a coupling to the inflaton as well. We explore the consequences of such a coupling in the context of single-field slow-roll inflation. Assuming an exponential potential for the quintessence field we show that the coupling to the inflaton causes the quintessence field to be attracted toward the minimum of the effective potential. If the coupling is large enough, the field is heavy and is located at the minimum. We show how this affects the expansion rate and the slow-roll of the inflaton field, and therefore the primordial perturbations generated during inflation. We further show that the coupling has an important impact on the processes of reheating and preheating

A Search for Gravitational Waves from Binary Mergers with a Single Observatory

We present a search for merging compact binary gravitational-wave sources that produce a signal appearing solely or primarily in a single detector. Past analyses have heavily relied on coincidence between multiple detectors to reduce non-astrophysical background. However, for $\sim40\%$ of the total time of the 2015-2017 LIGO-Virgo observing runs only a single detector was operating. We discuss the difficulties in assigning significance and calculating the probability of astrophysical origin for candidates observed primarily by a single detector, and suggest a straightforward resolution using a noise model designed to provide a conservative assessment given the observed data. We also describe a procedure to assess candidates observed in a single detector when multiple detectors are observing. We apply these methods to search for binary black hole (BBH) and binary neutron star (BNS) mergers in the open LIGO data spanning 2015-2017. The most promising candidate from our search is 170817+03:02:46UTC (probability of astrophysical origin $p_{\rm astro} \sim 0.4$): if astrophysical, this is consistent with a BBH merger with primary mass $67_{-15}^{+21}\,M_{\odot}$, suggestive of a hierarchical merger origin. We also apply our method to the analysis of GW190425 and find $p_{\rm astro} \sim 0.5$, though this value is highly dependent on assumptions about the noise and signal models.Comment: 11 pages, 5 figures, 2 tables. Updated to match ApJ version. Supplementary materials at https://github.com/gwastro/single-searc

We Could, but Should We? Ethical Considerations for Providing Access to GeoCities and Other Historical Digital Collections

We live in an era in which the ways that we can make sense of our past are evolving as more artifacts from that past become digital. At the same time, the responsibilities of traditional gatekeepers who have negotiated the ethics of historical data collection and use, such as librarians and archivists, are increasingly being sidelined by the system builders who decide whether and how to provide access to historical digital collections, often without sufficient reflection on the ethical issues at hand. It is our aim to better prepare system builders to grapple with these issues. This paper focuses discussions around one such digital collection from the dawn of the web, asking what sorts of analyses can and should be conducted on archival copies of the GeoCities web hosting platform that dates to 1994.This research was supported by the Natural Sciences and Engineering Research Council of Canada, the Social Sciences and Humanities Research Council of Canada, the US National Science Foundation (grants 1618695 and 1704369), the Andrew W. Mellon Foundation, Start Smart Labs, and Compute Canada