Geographic and Annual Influences on Optical Follow-up of Gravitational Wave Events

Srivastava, V.; Bhalerao, V.; Ravi, Aravind P.; Ghosh, Archisman; Bose, S.

doi:10.3847/1538-4357/aa62a4

Cited by 3 publications

(2 citation statements)

References 45 publications

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“…The direct detections of gravitational waves (GWs) from the mergers of black holes and neutron stars [1][2][3][4][5][6] by Advanced LIGO (aLIGO) [7] and Advanced Virgo (AdV) [8] detectors in the first and second observing runs (O1 and O2, respectively) have launched the era of GW astronomy [9,10]. In the coming years, the global network of ground-based detectors, comprising aLIGO, AdV, KAGRA [11] and LIGO-India [12] will not only increase the detection rate and facilitate the search for their possible electromagnetic counterparts [13][14][15] but also produce an unprecedentedly large amount of data, which can pose an interesting computational challenge for GW data analysis.…”

Section: Introductionmentioning

confidence: 99%

Random projections in gravitational wave searches of compact binaries

et al. 2019

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Random projection (RP) is a powerful dimension reduction technique widely used in analysis of high dimensional data. We demonstrate how this technique can be used to improve the computational efficiency of gravitational wave searches from compact binaries of neutron stars or black holes. Improvements in low-frequency response and bandwidth due to detector hardware upgrades pose a data analysis challenge in the advanced LIGO era as they result in increased redundancy in template databases and longer templates due to higher number of signal cycles in band. The RP-based methods presented here address both these issues within the same broad framework. We first use RP for an efficient, singular value decomposition inspired template matrix factorization and develop a geometric intuition for why this approach works. We then use RP to calculate approximate time-domain match correlations in a lower dimensional vector space. For searches over parameters corresponding to non-spinning binaries with a neutron star and a black hole, a combination of the two methods can reduce the total on-line computational cost by an order of magnitude over a nominal baseline. This can, in turn, help free-up computational resources needed to go beyond current spin-aligned searches to more complex ones involving generically spinning waveforms. arXiv:1801.04506v4 [gr-qc]

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Section: Introductionmentioning

confidence: 99%

Random projections in gravitational wave searches of compact binaries

et al. 2019

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“…Note that this is a sky-tiling strategy study, therefore we did not take into account observing conditions such as geographic location of the telescope or visibility conditions like phases of the moon and weather. Some of these aspects have been studied in the past (Rana et al 2017;Srivastava et al 2017) and others we are currently investigating.…”

Section: Introductionmentioning

confidence: 99%

Hunting Electromagnetic Counterparts of Gravitational-wave Events Using the Zwicky Transient Facility

Ghosh

Chatterjee

Kaplan

et al. 2017

PASP

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Detections of coalescing binary black holes by LIGO have opened a new window of transient astronomy. With increasing sensitivity of LIGO and participation of the Virgo detector in Cascina, Italy, we expect to soon detect coalescence of compact binary systems with one or more neutron stars. These are the prime targets for electromagnetic follow-up of gravitational wave triggers, which holds enormous promise of rich science. However, hunting for electromagnetic counterparts of gravitational wave events is a non-trivial task due to the sheer size of the error regions, which could span hundreds of square degrees. This may require deep observation with large field-of-view telescopes and/or use of galaxy catalogs. The Zwicky Transient facility (ZTF), scheduled to begin operation in 2017, is designed to cover such large sky-localization areas. In this work, we present the strategies of efficiently tiling the sky to facilitate the observation of the gravitational wave error regions using ZTF. To do this we used simulations consisting of 475 binary neutron star coalescences detected using a mix of twoand three-detector networks. Our studies reveal that, using two overlapping sets of ZTF tiles and a (modified) ranked-tiling algorithm, we can cover the gravitational-wave sky-localization regions with half as many pointings as a simple contour-covering algorithm. We then incorporated the ranked-tiling strategy to study our ability to observe the counterparts. This requires optimization of observation depth and localization area coverage. Our results show that observation in r-band with ∼ 600 seconds of integration time per pointing seems to be optimum for typical assumed brightnesses of electromagnetic counterparts, if we plan to spend equal amount of time per pointing. However, our results also reveal that we can gain by as much as 50% in detection efficiency if we linearly scale our integration time per pointing based on the tile probability.

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Measuring the Hubble constant: Gravitational wave observations meet galaxy clustering

2018

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We show how the distances to binary black holes measured in gravitational wave observations with ground-based interferometers can be used to constrain the redshift-distance relation and, thereby, measure the Hubble constant (H0). Gravitational wave observations of stellar-mass binary black holes are not expected to be accompanied by any electro-magnetic event that may help in accessing their redshifts. We address this deficiency by using an optical catalog to get the distribution of galaxies in redshift. Assuming that the clustering of the binaries is correlated with that of the galaxies, we propose using that correlation to measure H0. We show that employing this method on simulated data obtained for second-generation networks comprising at least three detectors, e.g., advanced LIGO -advanced VIRGO network, one can measure H0 with an accuracy of ∼ 8% with detection of a reference population of 25 binaries, each with black holes of mass 10M . As expected, with third-generation detectors like the Einstein telescope (ET), which will measure distances much more accurately and to greater depths, one can obtain better estimates for H0. Specifically, we show that with 25 observations, ET can constrain H0 to an accuracy of ∼7%. This method can also be used to estimate other cosmological parameters like the matter density Ωm and the dark energy equation of state.

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Geographic and Annual Influences on Optical Follow-up of Gravitational Wave Events

Cited by 3 publications

References 45 publications

Random projections in gravitational wave searches of compact binaries

Random projections in gravitational wave searches of compact binaries

Hunting Electromagnetic Counterparts of Gravitational-wave Events Using the Zwicky Transient Facility

Measuring the Hubble constant: Gravitational wave observations meet galaxy clustering

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