scholarly journals Lensing Magnification Seen by Gravitational Wave Detectors

Universe ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 19
Author(s):  
Giulia Cusin ◽  
Ruth Durrer ◽  
Irina Dvorkin

In this paper, we studied the gravitational lensing of gravitational wave events. The probability that an observed gravitational wave source has been (de-)amplified by a given amount is a detector-dependent quantity which depends on different ingredients: the lens distribution, the underlying distribution of sources and the detector sensitivity. The main objective of the present work was to introduce a semi-analytic approach to study the distribution of the magnification of a given source population observed with a given detector. The advantage of this approach is that each ingredient can be individually varied and tested. We computed the expected magnification as both a function of redshift and of the observedsource luminosity distance, which is the only quantity one can access via observation in the absence of an electromagnetic counterpart. As a case study, we then focus on the LIGO/Virgo network and on strong lensing (μ>1).

2020 ◽  
Vol 492 (3) ◽  
pp. 3359-3363 ◽  
Author(s):  
O Contigiani

ABSTRACT We gain insight into the effects of gravitational lensing on the estimated distribution of merging binaries observed through gravitational waves. We quantify the efficiency of magnification for gravitational wave events in the geometric optics limit, and we compare it to the electromagnetic case by making minimal assumptions about the distribution of intrinsic properties for the source population. We show that lensing effects leave a recognizable signature on the observed rates, and that they can be prominent only in the presence of an extremely steep mass function (or redshift evolution) and mainly at low inferred redshifts. We conclude that gravitational magnification does not represent a significant systematic for gravitational wave merger studies in the LIGO–Virgo era.


2021 ◽  
Vol 923 (1) ◽  
pp. 14
Author(s):  
R. Abbott ◽  
T. D. Abbott ◽  
S. Abraham ◽  
F. Acernese ◽  
K. Ackley ◽  
...  

Abstract We search for signatures of gravitational lensing in the gravitational-wave signals from compact binary coalescences detected by Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) and Advanced Virgo during O3a, the first half of their third observing run. We study: (1) the expected rate of lensing at current detector sensitivity and the implications of a non-observation of strong lensing or a stochastic gravitational-wave background on the merger-rate density at high redshift; (2) how the interpretation of individual high-mass events would change if they were found to be lensed; (3) the possibility of multiple images due to strong lensing by galaxies or galaxy clusters; and (4) possible wave-optics effects due to point-mass microlenses. Several pairs of signals in the multiple-image analysis show similar parameters and, in this sense, are nominally consistent with the strong lensing hypothesis. However, taking into account population priors, selection effects, and the prior odds against lensing, these events do not provide sufficient evidence for lensing. Overall, we find no compelling evidence for lensing in the observed gravitational-wave signals from any of these analyses.


Author(s):  
Nurul Nadjmi

Kepulauan Riau merupakan provinsi yang terdiri dari beberapa pulau diantaranya Pulau Batam, Pulau Bintan dan Pulau Karimun. Modal sosial merupakan serangkaian nilai dan norma informal yang dimiliki oleh kelompok masyarat dalam membagun kerjasamanya. Lingkup penelitian pada pembahasan ini adalah terfokus pada pengaruh modal sosial terhadap perkembangan pariwisata di Kepulauan Riau dalam hal ini Pulau Batam, Pulau Bintan, dan Pulau Karimun. Metode penelitian yang digunakan dalam penelitian ini adalah penelitian deskriptif kualitatif. Penelitian ini dikondisikan sebagai penelitian kualitatif melalui strategi studi kasus. Sistem pendekatan yang digunakan juga merupakan pendekatan deskriptif analitik. Melakukan pengamatan langsung, mengumpulkan data-data kemudian menghubungkannya dengan kajian teori yang digunakan. Lokus penelitian ini terdapat di Kepulauan Riau dengan melihat pengaruh modal sosial pada perkembangan pariwisata di ketiga pulau yaitu Pulau Batam, Pulau Bintan dan Pulau Karimun. Berdasarkan hasil survey yang saya lakukan di Kepulauan Riau, terutama pada ketiga pulau yaitu Pulau Batam, Pulau Bintan, dan Pulau Karimun, dari ketiga pulau tersebut ternyata pada Pulau Karimun perkembangan pariwisatanya tidak terlalu berkembang karena masyarakat yang tidak menerima adanya wisatawan terutama wisatawan mancanegara. Riau Islands is a province consisting of several islands including Batam Island, Bintan Island and Karimun Island. Social capital is a set of informal values ​​and norms that are owned by community groups in building cooperation. The scope of research in this discussion is focused on the influence of social capital on the development of tourism in the Riau Islands, in this case Batam Island, Bintan Island, and Karimun Island. The research method used in this research is descriptive qualitative research. This research is conditioned as qualitative research through a case study strategy. The system approach used is also a descriptive analytic approach. Make direct observations, collect data and then relate it to the study of the theories used. The locus of this research is in the Riau Islands by looking at the influence of social capital on the development of tourism in the three islands, namely Batam Island, Bintan Island and Karimun Island. Based on the results of a survey I conducted in the Riau Islands, especially on the three islands, namely Batam Island, Bintan Island, and Karimun Island, of the three islands, it turns out that on Karimun Island the development of tourism is not very developed because people do not accept tourists, especially foreign tourists.


Romanticism ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 69-80
Author(s):  
Ruth Knezevich

The genre of annotated verse represents an under-explored form of transporting romanticism. In annotated, locodescriptive poems like those in Anna Seward's Llangollen Vale, readers are invited to read not only the spatiality of the landscapes depicted in the verse but also the landscape of the page itself. Seward's poems, with their focus on understanding geographical, political, and historical spaces both real and imaginary, provide geocritical insight into poetic productions of the early Romantic era. Likewise, geocriticism offers a fresh and useful – even necessary – analytic approach to such poems. I adopt Anna Seward as a case study in annotated verse and argue that attending to the materiality and paratextuality of her work allows us to access the complexities of her poetry and prose as well as her position within the wider framework of transporting Romanticism.


2016 ◽  
Vol 69 (1) ◽  
pp. 9 ◽  
Author(s):  
Michitoshi Yoshida ◽  
Yousuke Utsumi ◽  
Nozomu Tominaga ◽  
Tomoki Morokuma ◽  
Masaomi Tanaka ◽  
...  

Author(s):  
Kris M. Markman

This chapter employs a conversation analytic approach to the study of group interaction in synchronous chat. Chat has been used in educational settings as an adjunct to traditional face-to-face classes and as part of distance learning. This case study examines how chat was used for virtual team meetings by specifically focusing on the structural features of chat conversation as they relate to various aspects of online teamwork. Chat conversations are characterized by disrupted turn adjacency and multiple conversational threads, requiring participants to adapt different strategies to maintain coherence. The advantages and disadvantages of using chat for group work are discussed, and suggestions for implementing chat in education settings are presented.


2020 ◽  
Vol 493 (3) ◽  
pp. 3379-3397 ◽  
Author(s):  
A Rossi ◽  
G Stratta ◽  
E Maiorano ◽  
D Spighi ◽  
N Masetti ◽  
...  

ABSTRACT Multimessenger astronomy received a great boost following the discovery of kilonova (KN) AT2017gfo, the optical counterpart of the gravitational wave source GW170817 associated with the short gamma-ray burst GRB 170817A. AT2017gfo was the first KN that could be extensively monitored in time using both photometry and spectroscopy. Previously, only few candidates have been observed against the glare of short GRB afterglows. In this work, we aim to search the fingerprints of AT2017gfo-like KN emissions in the optical/NIR light curves of 39 short GRBs with known redshift. For the first time, our results allow us to study separately the range of luminosity of the blue and red components of AT2017gfo-like kilonovae in short GRBs. In particular, the red component is similar in luminosity to AT2017gfo, while the blue KN can be more than 10 times brighter. Finally, we exclude a KN as luminous as AT2017gfo in GRBs 050509B and 061201.


2020 ◽  
Vol 497 (1) ◽  
pp. 204-209 ◽  
Author(s):  
Hai Yu ◽  
Pengjie Zhang ◽  
Fa-Yin Wang

ABSTRACT Standard siren cosmology of gravitational wave (GW) merger events relies on the identification of host galaxies and their redshifts. But this can be highly challenging due to numerous candidates of galaxies in the GW localization area. We point out that the number of candidates can be reduced by orders of magnitude for strongly lensed GW events, due to extra observational constraints. For the next-generation GW detectors like Einstein Telescope (ET), we estimate that this number is usually significantly less than one, as long as the GW localization uncertainty is better than $\sim 10\, \rm deg^2$. This implies that the unique identification of the host galaxy of lensed GW event detected by ET and Cosmic Explorer (CE) is possible. This provides us a promising opportunity to measure the redshift of the GW event and facilitate the standard siren cosmology. We also discuss its potential applications in understanding the evolution process and environment of the GW event.


Sign in / Sign up

Export Citation Format

Share Document