Bayes-X: a Bayesian inference tool for the analysis of X-ray observations of galaxy clusters

We present the first public release of our Bayesian inference tool, Bayes-X, for the analysis of X-ray observations of galaxy clusters. We illustrate the use of Bayes-X by analysing a set of four simulated clusters at z=0.2-0.9 as they would be observed by a Chandra-like X-ray observatory. In both the simulations and the analysis pipeline we assume that the dark matter density follows a spherically-symmetric Navarro, Frenk and White (NFW) profile and that the gas pressure is described by a generalised NFW (GNFW) profile. We then perform four sets of analyses. By numerically exploring the joint probability distribution of the cluster parameters given simulated Chandra-like data, we show that the model and analysis technique can robustly return the simulated cluster input quantities, constrain the cluster physical parameters and reveal the degeneracies among the model parameters and cluster physical parameters. We then analyse Chandra data on the nearby cluster, A262, and derive the cluster physical profiles. To illustrate the performance of the Bayesian model selection, we also carried out analyses assuming an Einasto profile for the matter density and calculated the Bayes factor. The results of the model selection analyses for the simulated data favour the NFW model as expected. However, we find that the Einasto profile is preferred in the analysis of A262. The Bayes-X software, which is implemented in Fortran 90, is available at http://www.mrao.cam.ac.uk/facilities/software/bayesx/.Comment: 22 pages, 11 figure

Further Sunyaev-Zel'dovich observations of two Planck ERCSC clusters with the Arcminute Microkelvin Imager

We present follow-up observations of two galaxy clusters detected blindly via the Sunyaev-Zel'dovich (SZ) effect and released in the Planck Early Release Compact Source Catalogue. We use the Arcminute Microkelvin Imager, a dual-array 14-18 GHz radio interferometer. After radio source subtraction, we find a SZ decrement of integrated flux density -1.08+/-0.10 mJy toward PLCKESZ G121.11+57.01, and improve the position measurement of the cluster, finding the centre to be RA 12 59 36.4, Dec +60 04 46.8, to an accuracy of 20 arcseconds. The region of PLCKESZ G115.71+17.52 contains strong extended emission, so we are unable to confirm the presence of this cluster via the SZ effect.Comment: 4 tables, 3 figures, revised after referee's comments and resubmitted to MNRA

The search for black hole binaries using a genetic algorithm

In this work we use genetic algorithm to search for the gravitational wave signal from the inspiralling massive Black Hole binaries in the simulated LISA data. We consider a single signal in the Gaussian instrumental noise. This is a first step in preparation for analysis of the third round of the mock LISA data challenge. We have extended a genetic algorithm utilizing the properties of the signal and the detector response function. The performance of this method is comparable, if not better, to already existing algorithms.Comment: 11 pages, 4 figures, proceeding for GWDAW13 (Puerto Rico

Distribution and abundance of elasmobranchs in the Indian EEZ

Elasmobranchs were present in 100 trawling stations of depth up to 170 m, along the Indian EEZ, where the FORV Sagar Sampada carried out fishing operations during her first hundred cruises. Abundance and distribution of sharks, skates and rays in the different latitudinal zones are discussed. The catchable potential of this resource up to the 50 m depth zone has been estimated as 64934 tonne. Elasmobranchs being on exploitable resource, the potential yield beyond 50 m in the EEZ is estimated as 88985 m tonne. Though the maximum catch was obtained from the southwest area, the maximum c.p.u of elasmobranchs was observed to be along the northwest region

Role of Keystone Species in Aquatic Ecosystem

A keystone species is a species that has a disproportionately large effect on its environment relative to its abundance. Such species play a critical role in maintaining the structure of an ecological community, affecting many other organism s in an ecosystem and helping to determine the types and numbers of various other species in the community

Bayesian analysis of weak gravitational lensing and Sunyaev-Zel'dovich data for six galaxy clusters

We present an analysis of observations made with the Arcminute Microkelvin Imager (AMI) and the Canada-France-Hawaii Telescope (CFHT) of six galaxy clusters in a redshift range of 0.16--0.41. The cluster gas is modelled using the Sunyaev--Zel'dovich (SZ) data provided by AMI, while the total mass is modelled using the lensing data from the CFHT. In this paper, we: i) find very good agreement between SZ measurements (assuming large-scale virialisation and a gas-fraction prior) and lensing measurements of the total cluster masses out to r_200; ii) perform the first multiple-component weak-lensing analysis of A115; iii) confirm the unusual separation between the gas and mass components in A1914; iv) jointly analyse the SZ and lensing data for the relaxed cluster A611, confirming our use of a simulation-derived mass-temperature relation for parameterizing measurements of the SZ effect.Comment: 22 pages, 12 figures, 12 tables, published by MNRA

Impact of subdominant modes on the interpretation of gravitational-wave signals from heavy binary black hole systems

Over the past year, a handful of new gravitational wave models have been developed to include multiple harmonic modes thereby enabling for the first time fully Bayesian inference studies including higher modes to be performed. Using one recently developed numerical relativity surrogate model, NRHybSur3dq8, we investigate the importance of higher modes on parameter inference of coalescing massive binary black holes. We focus on examples relevant to the current three-detector network of observatories, with a detector-frame mass set to 120 M⊙ and with signal amplitude values that are consistent with plausible candidates for the next few observing runs. We show that for such systems the higher mode content will be important for interpreting coalescing binary black holes, reducing systematic bias, and computing properties of the remnant object. Even for comparable-mass binaries and at low signal amplitude, the omission of higher modes can influence posterior probability distributions. We discuss the impact of our results on source population inference and self-consistency tests of general relativity. Our work can be used to better understand asymmetric binary black hole merger events, such as GW190412. Higher modes are critical for such systems, and their omission usually produces substantial parameter biases

Factors associated with anemia among women of the reproductive age group in Thatta district: Study protocol

Background: Maternal anemia is a leading public health issue placing pregnant women at higher risk of low birth weight, preterm birth, perinatal mortality, and neonatal mortality. Women in developing countries are at higher risk of anemia which could be either due to micronutrient deficiencies, hemoglobinopathies, infections or other socio-demographic factors. Thus, it is highly essential to explore the factors of anemia among women of the reproductive age group in order to design suitable interventions. The primary objective of this study is to assess the biological and socio-demographic factors that are associated with anemia among the women of the reproductive age group in Thatta district.Methods: An exploratory mixed method study using quantitative and qualitative approaches will be conducted in district Thatta Pakistan from September 2018 to January 2019. In the qualitative phase, data will be collected through focus group discussions and key informant interviews to understand the perceptions of women, their husbands and healthcare providers about anemia. In addition, a quantitative approach using cross-sectional study will be conducted to determine biological and socio-demographic factors associated with anemia. Approximately 150 non-pregnant women and their spouses will be included in the quantitative component of the study. In addition to thematic analysis for the qualitative component, Logistic regression will be done to calculate adjusted Odds ratios with their respective 95% CIs to assess the factors associated with anemia.Discussion: The better understanding of biological, socio-demographic factors and community perceptions of anemia will help us to design strategies and interventions to better address anemia during the reproductive cycle in rural areas of Pakistan. This will help the researchers and policymakers to take the appropriate action accordingly by designing suitable approaches to address the specific type of anemia in the rural population of Pakistan. This will, in turn, reduce the chances of adverse maternal and fetal outcomes associated with anemia