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

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

First Measurement of the Hubble Constant from a Dark Standard Siren using the Dark Energy Survey Galaxies and the LIGO/Virgo Binary-Black-hole Merger GW170814

We present a multi-messenger measurement of the Hubble constant H 0 using the binary–black-hole merger GW170814 as a standard siren, combined with a photometric redshift catalog from the Dark Energy Survey (DES). The luminosity distance is obtained from the gravitational wave signal detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO)/Virgo Collaboration (LVC) on 2017 August 14, and the redshift information is provided by the DES Year 3 data. Black hole mergers such as GW170814 are expected to lack bright electromagnetic emission to uniquely identify their host galaxies and build an object-by-object Hubble diagram. However, they are suitable for a statistical measurement, provided that a galaxy catalog of adequate depth and redshift completion is available. Here we present the first Hubble parameter measurement using a black hole merger. Our analysis results in ${H}_{0}={75}_{-32}^{+40}\,\mathrm{km}\,{{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1}$, which is consistent with both SN Ia and cosmic microwave background measurements of the Hubble constant. The quoted 68% credible region comprises 60% of the uniform prior range [20, 140] km s−1 Mpc−1, and it depends on the assumed prior range. If we take a broader prior of [10, 220] km s−1 Mpc−1, we find {H}_{0 {78}_{-24}^{+96}\,\mathrm{km}\,{{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1} (57% of the prior range). Although a weak constraint on the Hubble constant from a single event is expected using the dark siren method, a multifold increase in the LVC event rate is anticipated in the coming years and combinations of many sirens will lead to improved constraints on H 0

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

Apoptosis in labial salivary glands from Sjögren's syndrome (SS) patients: comparison with human T lymphotropic virus-I (HTLV-I)-seronegative and -seropositive SS patients

Apoptosis is a type of cell death that occurs during morphogenesis and development of the immune system. One of the mechanisms is mediated through the Fas and Fas ligand (FasL) pathway. To determine the possible involvement of Fas and its ligand in salivary gland destruction, we analysed the appearance of nuclei with DNA fragmentation by using nick end labelling (TUNEL) and the expression of Fas and FasL by immunohistochemistry in labial salivary glands. Furthermore, we compared the features of apoptosis in labial salivary glands between HTLV-I− and HTLV-I+ SS. When the frozen sections of 10 primary SS patients in the absence of anti-HTLV-I antibody were examined, several apoptotic cells were found in the acinar and ductal epithelial cells as well as infiltrated mononuclear cells. Both Fas and FasL were detected in the infiltrated mononuclear cells. Acinar epithelial cells, which are surrounded by FasL+ mononuclear cells, were also double-positive with Fas and FasL, although the expression of FasL was localized at their apical border, suggesting that apoptosis of mononuclear cells was achieved by activation-induced mechanisms through Fas/FasL pathways, and that of acinar epithelial cells was mediated by FasL derived from either acinar epithelial cells themselves or infiltrated mononuclear cells. Interestingly, Fas expression in ductal epithelial cells was localized around the lumen side of the ducts, indicating that FasL secreted from acinar epithelial cells may induce Fas-mediated apoptosis of ductal epithelial cells. We also studied the labial salivary glands from nine SS patients with anti-HTLV-I antibodies. There was no significant difference in the occurrence of apoptotic cells or in the expression of Fas and FasL between HTLV-I+ and HTLV-I− SS patients. It was of note that neither the expression of Fas and FasL nor the presence of apoptotic cells were determined in labial salivary glands from subjects without SS. These findings indicate that Fas-mediated apoptosis in salivary glands could be involved in the pathological manifestations of SS, irrespective of HTLV-I seropositivity

Palliative Care in Pediatric Oncology

Pediatric palliative care (PPC) in oncology is the active total care of the child’s body, mind, and spirit and involves giving support to the family. Pediatric palliative oncology includes patients across the age spectrum from infancy through young adulthood, and can be embodied as a philosophy of care or applied by an interdisciplinary team of experts. PPC should be initiated at the time of a child’s cancer diagnosis and continued regardless of whether or not the child receives treatment directed at the cancer. PPC aims to prevent and relieve suffering across multiple realms (physical, psychological, social, and existential or spiritual) and enhance quality of life. PPC can be either primary (administered by the primary oncology team) or specialty-focused (administered by an expert or team of experts in PPC), depending on the unique needs of the patient, family, and health care team. Despite evidence demonstrating the benefits of PPC, numerous barriers to its implementation remain. Ongoing education and research are necessary to support consistent access for patients, families, and health care clinicians