Measuring eccentricity in binary black hole inspirals with gravitational waves

When binary black holes form in the field, it is expected that their orbits typically circularize before coalescence. In galactic nuclei and globular clusters, binary black holes can form dynamically. Recent results suggest that $\approx5\%$ of mergers in globular clusters result from three-body interactions. These three-body interactions are expected to induce significant orbital eccentricity $\gtrsim 0.1$ when they enter the Advanced LIGO band at a gravitational-wave frequency of 10 Hz. Measurements of binary black hole eccentricity therefore provide a means for determining whether or not dynamic formation is the primary channel for producing binary black hole mergers. We present a framework for performing Bayesian parameter estimation on gravitational-wave observations of black hole inspirals. Using this framework, and employing the non-spinning, inspiral-only EccentricFD waveform approximant, we determine the minimum detectable eccentricity for an event with masses and distance similar to GW150914. At design sensitivity, we find that the current generation of advanced observatories will be sensitive to orbital eccentricities of $\gtrsim0.05$ at a gravitational-wave frequency of 10 Hz, demonstrating that existing detectors can use eccentricity to distinguish between circular field binaries and globular cluster triples. We compare this result to eccentricity distributions predicted to result from three black hole binary formation channels, showing that measurements of eccentricity could be used to infer the population properties of binary black holes.Comment: 12 pages, 7 figures, 2 table

The history of Andøya Rocket Range

Just 5 years after Sputnik, on 18 August 1962, Norway launched the first sounding rocket from Andøya in northern Norway. The establishment of Andøya Rocket Range (ARR), in the Arctic and right in the middle of the night-time auroral zone, gave the scientists unique opportunities for studies of the complex processes in the auroral ionosphere and upper atmosphere. In close cooperation with the users, ARR gradually developed its technical and scientific infrastructure and is now one of the world's leading observatories in this field. ARR has also established a launch site at Svalbard, and sounding rockets from both ranges can reach far into the Arctic to study the cusp region and the daytime aurora. The ground-based instruments comprise sophisticated radars and lidars as well as passive instruments. ARR also plays an active role in space education. In 2014 Andøya Rocket Range changed its name to Andøya Space Center (ASC; https://www.andoyaspace.no, last access: 23 November 2018). This change reflects the fact that the activities now comprise much more than sounding rocket launches. ASC is an important company both nationally and in the local community of Andenes. ASC now has a staff of 95 and an annual turnover of NOK&thinsp;150&thinsp;million.</p

Middle Atmosphere Cooperation/Summer in Northern Europe (MAC/SINE) and MAC/Epsilon

Two major international campaigns dedicated to the study of middle atmosphere dynamics in high latitudes were successfully completed in 1987. MAC/SINE (Middle Atmosphere Cooperation/Summer in Northern Europe) was carried out during the period 7 June to 19 July, whereas MAC/Epsilon took place in the period 12 October to 15 November. In both campaigns a large number of ground based and rocket techniques were used in a concerted effort to map the dynamical structure of the middle atmosphere over Northern Europe. Although the analysis of the observations has only just started, it is clear that a large and unique data set was obtained, which is believed will provide new insight into the dynamical processes in this interesting region of the atmosphere. A brief overview of the campaigns, their scientific aims, organization and structure is presented

The use of dc-probe measurements in the middle atmosphere program

The middle atmosphere is weakly ionized, collision dominated plasma. Rocket-borne dc probes have proven effective in measuring conductivity and electron and ion concentrations in this plasma, and in some cases electron temperatures and ion composition were observed. During MAP, dc probes were also used successfully to study turbulence in the middle atmosphere, using the plasma as a passive tracer for the dynamical processes in the nonionized gas. Basic principles are reviewed of the dc-probe technique and examples are presented of results obtained during MAP

Sensitivity curves for searches for gravitational-wave backgrounds

We propose a graphical representation of detector sensitivity curves for stochastic gravitational-wave backgrounds that takes into account the increase in sensitivity that comes from integrating over frequency in addition to integrating over time. This method is valid for backgrounds that have a power-law spectrum in the analysis band. We call these graphs “power-law integrated curves.” For simplicity, we consider cross-correlation searches for unpolarized and isotropic stochastic backgrounds using two or more detectors. We apply our method to construct power-law integrated sensitivity curves for second-generation ground-based detectors such as Advanced LIGO, space-based detectors such as LISA and the Big Bang Observer, and timing residuals from a pulsar timing array. The code used to produce these plots is available at https://dcc.ligo.org/LIGO-P1300115/public for researchers interested in constructing similar sensitivity curves

Correlated magnetic noise in global networks of gravitational-wave detectors: Observations and implications

One of the most ambitious goals of gravitational-wave astronomy is to observe the stochastic gravitational-wave background. Correlated noise in two or more detectors can introduce a systematic error, which limits the sensitivity of stochastic searches. We report on measurements of correlated magnetic noise from Schumann resonances at the widely separated LIGO and Virgo detectors. We investigate the effect of this noise on a global network of gravitational-wave detectors and derive a constraint on the allowable coupling of environmental magnetic fields to test mass motion in gravitational-wave detectors. We find that while correlated noise from global electromagnetic fields could be safely ignored for initial LIGO stochastic searches, it could severely impact Advanced LIGO, Advanced Virgo, KAGRA, as well as third-generation detectors

Photoinjector-generation of a flat electron beam with transverse emittance ratio of 100

The generation of a flat electron beam directly from a photoinjector is an attractive alternative to the electron damping ring as envisioned for linear colliders. It also has potential applications to light sources such as the generation of ultra-short x-ray pulses or Smith-Purcell free electron lasers. In this Letter, we report on the experimental generation of a flat-beam with a measured transverse emittance ratio of $100\pm 20.2$ for a bunch charge of $\sim 0.5$ nC; the smaller measured normalized root-mean-square emittance is $\sim 0.4$ $\mu$m and is limited by the resolution of our experimental setup. The experimental data, obtained at the Fermilab/NICADD Photoinjector Laboratory, are compared with numerical simulations and the expected scaling laws.Comment: 5 pages, 3 figure

Irregular structures observed below 71 km in the night-time polar D-region

International audienceA new rocket range, SvalRak, was opened in November 1997 at Ny-Ålesund (79°N) in the Svalbard archipelago. The first instrumented rocket was launched on 20 November, 1997, at 1730 UT during geomagnetically quiet conditions. The payload was instrumented to measure plasma parameters in the mesosphere and lower thermosphere, but the payload only reached an altitude of 71 km. This resulted in a very flat trajectory through the lower D-region. The positive ion concentrations were larger than expected, and some unexpected plasma irregularities were observed below 71 km. The irregularities were typically 100 m in spatial extent, with plasma densities a factor of two to five above the ambient background. In the dark polar night the plasma below 71 km must consist mainly of positive and negative ions and the only conceivable ionising radiation is a flux of energetic particles. Furthermore only relativistic electrons have the large energies and the small gyro radii required in order to explain the observed spatial structure. The source of these electrons is uncertain

Acceptability and Feasibility of Reiki for Symptom Management in Children Receiving Palliative Care

Complementary therapies are chosen by parents of children receiving palliative care to augment the use of traditional medications for symptom management without the increased side effects additional medications may bring. Pain and anxiety are common symptoms for children receiving palliative care. Reiki therapy is a light touch therapy that has been examined in adults but not with children until recently. This dissertation addresses the evidence for complementary therapies for children experiencing pain and anxiety, Reiki therapy for pain and anxiety in adults, and evidence based complementary therapies for young children considering developmental stage. The main study is a quasi-experimental mixed methods pilot study design examining the acceptability and the feasibility of a Reiki therapy intervention for children ages 7 to 16 years receiving palliative care. We measured pain, anxiety, and relaxation operationalized as heart and respiratory rates pre and post Reiki therapy interventions at each of two home visits. We completed a structured interview separately with parents and children to elicit their views on the Reiki therapy experience. Paired student t-tests or Wilcoxon signed rank tests were calculated comparing the pre and post Reiki scores separately for verbal and non-verbal children for each treatment, over the entire intervention, and independent sample t-tests or Mann-Whitney tests comparing children based on demographic variables. We approached 24 child-parent dyads, 21 (87.5%) agreed to participate and signed consents while 3 (12.5%) declined to participate. Of the 21 dyads, 16 completed the study (eight verbal and eight non-verbal children). Statistical significance was obtained for verbal children for heart rate for treatment two (t=3.550, p = 0.009) and for nonverbal children for pain for treatment two (Z = -2.023, p = 0.063); however effect sizes using Cohen’s d levels were medium to large for both verbal and non-verbal children for pain and anxiety. Children and their parents told us their experiences with Reiki therapy. Themes found in interviews augment the quantitative results. Themes included Feeling Better, Hard to Judge, and Still Going On, which helped clarify the quantitative results. Results support further study of Reiki therapy for symptom management in children