818 research outputs found
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Search for Eccentric Binary Black Hole Mergers with Advanced LIGO and Advanced Virgo during Their First and Second Observing Runs
When formed through dynamical interactions, stellar-mass binary black holes (BBHs) may retain eccentric orbits (e > 0.1 at 10 Hz) detectable by ground-based gravitational-wave detectors. Eccentricity can therefore be used to differentiate dynamically formed binaries from isolated BBH mergers. Current template-based gravitational-wave searches do not use waveform models associated with eccentric orbits, rendering the search less efficient for eccentric binary systems. Here we present the results of a search for BBH mergers that inspiral in eccentric orbits using data from the first and second observing runs (O1 and O2) of Advanced LIGO and Advanced Virgo. We carried out the search with the coherent WaveBurst algorithm, which uses minimal assumptions on the signal morphology and does not rely on binary waveform templates. We show that it is sensitive to binary mergers with a detection range that is weakly dependent on eccentricity for all bound systems. Our search did not identify any new binary merger candidates. We interpret these results in light of eccentric binary formation models. We rule out formation channels with rates ⪆100 Gpc-3 yr-1 for e > 0.1, assuming a black hole mass spectrum with a power-law index ≲2
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Search for intermediate mass black hole binaries in the first and second observing runs of the Advanced LIGO and Virgo network
Gravitational-wave astronomy has been firmly established with the detection of gravitational waves from the merger of ten stellar-mass binary black holes and a neutron star binary. This paper reports on the all-sky search for gravitational waves from intermediate mass black hole binaries in the first and second observing runs of the Advanced LIGO and Virgo network. The search uses three independent algorithms: two based on matched filtering of the data with waveform templates of gravitational-wave signals from compact binaries, and a third, model-independent algorithm that employs no signal model for the incoming signal. No intermediate mass black hole binary event is detected in this search. Consequently, we place upper limits on the merger rate density for a family of intermediate mass black hole binaries. In particular, we choose sources with total masses M=m1+m2ϵ[120,800] M and mass ratios q=m2/m1ϵ[0.1,1.0]. For the first time, this calculation is done using numerical relativity waveforms (which include higher modes) as models of the real emitted signal. We place a most stringent upper limit of 0.20 Gpc-3 yr-1 (in comoving units at the 90% confidence level) for equal-mass binaries with individual masses m1,2=100 M and dimensionless spins χ1,2=0.8 aligned with the orbital angular momentum of the binary. This improves by a factor of ∼5 that reported after Advanced LIGO's first observing run
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All-sky search for short gravitational-wave bursts in the second Advanced LIGO and Advanced Virgo run
We present the results of a search for short-duration gravitational-wave transients in the data from the second observing run of Advanced LIGO and Advanced Virgo. We search for gravitational-wave transients with a duration of milliseconds to approximately one second in the 32-4096 Hz frequency band with minimal assumptions about the signal properties, thus targeting a wide variety of sources. We also perform a matched-filter search for gravitational-wave transients from cosmic string cusps for which the waveform is well modeled. The unmodeled search detected gravitational waves from several binary black hole mergers which have been identified by previous analyses. No other significant events have been found by either the unmodeled search or the cosmic string search. We thus present the search sensitivities for a variety of signal waveforms and report upper limits on the source rate density as a function of the characteristic frequency of the signal. These upper limits are a factor of 3 lower than the first observing run, with a 50% detection probability for gravitational-wave emissions with energies of ∼10-9 Mc2 at 153 Hz. For the search dedicated to cosmic string cusps we consider several loop distribution models, and present updated constraints from the same search done in the first observing run
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Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model
We present results from a semicoherent search for continuous gravitational
waves from the low-mass X-ray binary Scorpius X-1, using a hidden Markov model
(HMM) to track spin wandering. This search improves on previous HMM-based
searches of LIGO data by using an improved frequency domain matched filter, the
-statistic, and by analysing data from Advanced LIGO's second
observing run. In the frequency range searched, from to
, we find no evidence of gravitational radiation. At
, the most sensitive search frequency, we report an upper
limit on gravitational wave strain (at 95\% confidence) of when marginalising over source inclination angle. This is the
most sensitive search for Scorpius X-1, to date, that is specifically designed
to be robust in the presence of spin wandering
Cross-lingual Editing in Multilingual Language Models
The training of large language models (LLMs) necessitates substantial data
and computational resources, and updating outdated LLMs entails significant
efforts and resources. While numerous model editing techniques (METs) have
emerged to efficiently update model outputs without retraining, their
effectiveness in multilingual LLMs, where knowledge is stored in diverse
languages, remains an underexplored research area. This research paper
introduces the cross-lingual model editing (\textbf{XME}) paradigm, wherein a
fact is edited in one language, and the subsequent update propagation is
observed across other languages. To investigate the XME paradigm, we conducted
experiments using BLOOM, mBERT, and XLM-RoBERTa using the two writing scripts:
\textit{Latin} (English, French, and Spanish) and \textit{Indic} (Hindi,
Gujarati, and Bengali). The results reveal notable performance limitations of
state-of-the-art METs under the XME setting, mainly when the languages involved
belong to two distinct script families. These findings highlight the need for
further research and development of XME techniques to address these challenges.
For more comprehensive information, the dataset used in this research and the
associated code are publicly available at the following
URL\url{https://github.com/lingo-iitgn/XME}.Comment: Accepted at EACL 202
Periodic Peritoneal Dialysis in End Stage Renal Disease: Is it Still Relevant? A Single Center Study from India
Background: High cost of maintenance hemodialysis (HD) and continuous ambulatory peritoneal dialysis (PD) in India has made renal replacement therapy out of reach of many patients with end stage renal disease (ESRD). Repeated puncture PD although inferior to HD biochemically, is easily and freely available across Rajasthan, India, and is simple to perform, and does not require sophisticated machines, thus making it an attractive option for dialysis for ESRD. Aim: To analyze the outcomes of periodic PD in patients with ESRD requiring dialysis support. Subjects and Methods: A prospective study analyzing the data of patients who underwent PD between August 2010 and January 2013 in Sawai Man Singh Hospital, Jaipur, India was conducted. Patients were divided into three groups based on the time period between first and second session of PD. Detailed demographic and clinical data during the study period were collected along with PD related complications. The main outcome studied was technique survival 1 year post initiation of PD. Results: 234 patients received an initial session of PD, of which 174 had a good response and were included in the study. 19 patients received the second PD within 7 days of first (Group 1), 45 patients within 8–14 days (Group 2) and 110 patients within 15–21 days (Group 3). The overall 1 year technique survival was 68.4% (91/133), with a rate of 50% (5/10), 56.8% (21/37), and 75.6% (65/86) for Group 1, Group 2, and Group 3, respectively. The time duration between first and second PD proved to be reliable indicator of the subsequent response, with a technique survival rate significantly lower in Group 1 patients compared to Groups 2 and 3 (P = 0.04). Median dialysis free days were 11, 16 and 21 days in Group 1, Group 2, and Group 3, respectively. Peritonitis rate observed was 2.1% (49/2261) during the study period. Conclusion: Periodic PD is a simple, safe and cheap procedure, which can be considered as used as a palliative measure in terminal uremia in underprivileged areas.Keywords: Peritoneal dialysis, End stage renal disease, Renal replacement therap
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
International audienceWe 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 , 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 (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
Creep Failure Estimation of Distribution Transformers
Abstract This paper details about reasons of failure in distribution transformers (DTs). It has been proposed that creep may be a major reason for such failures. The effect of stress, temperature, and material on steady state creep rate on aluminium and copper wires (used in 25 kVA distribution transformers) has been presented. Proposed study confirms that the failure rate of aluminium wound DTs is higher than the failure rate of copper wound DTs in power deficient areas and poor distribution networks. The higher failure rate of aluminium wound DTs has been attributed to the elevated steady state creep rate of the aluminium wire than copper wire
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