First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data

Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a fully coherent search, based on matched filtering, which uses the position and rotational parameters obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signalto- noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have been developed, allowing a fully coherent search for gravitational waves from known pulsars over a fraction of a hertz and several spin-down values. In this paper we describe a narrow-band search of 11 pulsars using data from Advanced LIGO’s first observing run. Although we have found several initial outliers, further studies show no significant evidence for the presence of a gravitational wave signal. Finally, we have placed upper limits on the signal strain amplitude lower than the spin-down limit for 5 of the 11 targets over the bands searched; in the case of J1813-1749 the spin-down limit has been beaten for the first time. For an additional 3 targets, the median upper limit across the search bands is below the spin-down limit. This is the most sensitive narrow-band search for continuous gravitational waves carried out so far

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Multi-messenger Observations of a Binary Neutron Star Merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ∼ 1.7 {{s}} with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of {40}-8+8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 {M}ȯ . An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ∼ 40 {{Mpc}}) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ∼ 9 and ∼ 16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.</p

Evaluation of the acceptability of a vaccine against herpes zoster in the over 50 years old: An Italian observational study

Objective: The aim of the study was to evaluate awareness of the varicella zoster virus and the acceptability of the newly available herpes zoster (HZ) vaccine in the over 50 years old general population. Design: The research was observational. Setting: The study was carried out in Ferrara by administering a questionnaire to patients of the Local Health Authority (LHA), general practitioners (GPs) and Public Health Department outpatient clinics. Participants: The questionnaire was completed by 1001 residents of Ferrara Province. Results: Of the respondents, 98% and 95% (57% female) were aware of varicella and HZ, respectively, but 91% were unaware of the HZ vaccine. Nevertheless, 58% declared that they were in favour of vaccination in this regard, and the acceptability of the vaccine was positively affected by: age ( p=0.005); knowing someone who had suffered from HZ (p=0.05); being in favour of vaccination in general (p<0.0001); receiving advice to do so from their GP (p<0.0001) and willingness to get vaccinated even on a fee-paying basis (p<0.0001). Indeed, most (73%) respondents were willing to pay to get vaccinated, indicating an ideal cost of €50. Higher education (p=0.04), being in favour of vaccinations in general (p<0.0001) and GP advice (p<0.0001) positively affected this choice. Furthermore, 61% of the participants initially unfavourable (p<0.0001) to this immunisation would change their decision not to vaccinate thanks to their GP's advice. Conclusions: This study assessed the level of awareness and the attitudes of the population aged over 50 years, highlighting aspects to be focused on in the promotion of the HZ vaccine

Principes de composition des ecoles d'Italie. Tome 2 / adoptés par le Gouvernement français pour servir à l'instruction des elèves des maîtrises de cathédrales. Ouvrage classique formé de la réunion des modèles les plus parfaits en tout genre, enrichi d'un texte méthodique rédigé selon l'enseignement des ecoles les plus célèbres et des ecrivains didactiques les plus estimés. Dédié a S.M. l'Empereur et Roi par Alexandre Choron. Tome premier [-troisième]

Appartient à l’ensemble documentaire : MethMusiqAvec mode text