scholarly journals Data-driven Expectations for Electromagnetic Counterpart Searches Based on LIGO/Virgo Public Alerts

2022 ◽  
Vol 924 (2) ◽  
pp. 54
Author(s):  
Polina Petrov ◽  
Leo P. Singer ◽  
Michael W. Coughlin ◽  
Vishwesh Kumar ◽  
Mouza Almualla ◽  
...  
Keyword(s):  
Data Analysis ◽  
Neutron Star ◽  
Gravitational Wave ◽  
Gamma Ray ◽  
Data Driven ◽  
Wave Localization ◽  
Localization Accuracy ◽  
Binary Neutron Star ◽  
Data Release

Abstract Searches for electromagnetic counterparts of gravitational-wave signals have redoubled since the first detection in 2017 of a binary neutron star merger with a gamma-ray burst, optical/infrared kilonova, and panchromatic afterglow. Yet, one LIGO/Virgo observing run later, there has not yet been a second, secure identification of an electromagnetic counterpart. This is not surprising given that the localization uncertainties of events in LIGO and Virgo’s third observing run, O3, were much larger than predicted. We explain this by showing that improvements in data analysis that now allow LIGO/Virgo to detect weaker and hence more poorly localized events have increased the overall number of detections, of which well-localized, gold-plated events make up a smaller proportion overall. We present simulations of the next two LIGO/Virgo/KAGRA observing runs, O4 and O5, that are grounded in the statistics of O3 public alerts. To illustrate the significant impact that the updated predictions can have, we study the follow-up strategy for the Zwicky Transient Facility. Realistic and timely forecasting of gravitational-wave localization accuracy is paramount given the large commitments of telescope time and the need to prioritize which events are followed up. We include a data release of our simulated localizations as a public proposal planning resource for astronomers.

scholarly journals The first six months of the Advanced LIGO’s and Advanced Virgo’s third observing run with GRANDMA

2019 ◽  
Vol 492 (3) ◽  
pp. 3904-3927 ◽  
Author(s):  
S Antier ◽  
S Agayeva ◽  
V Aivazyan ◽  
S Alishov ◽  
E Arbouch ◽  
...  
Keyword(s):  
Neutron Star ◽  
Gravitational Wave ◽  
Gamma Ray ◽  
Spatial Localization ◽  
Gamma Ray Bursts ◽  
Binary Neutron Star ◽  
The Third ◽  
Transient Events ◽  
Tools And Methods

ABSTRACT We present the Global Rapid Advanced Network Devoted to the Multi-messenger Addicts (GRANDMA). The network consists of 21 telescopes with both photometric and spectroscopic facilities. They are connected together thanks to a dedicated infrastructure. The network aims at coordinating the observations of large sky position estimates of transient events to enhance their follow-up and reduce the delay between the initial detection and optical confirmation. The GRANDMA programme mainly focuses on follow-up of gravitational-wave alerts to find and characterize the electromagnetic counterpart during the third observational campaign of the Advanced LIGO and Advanced Virgo detectors. But it allows for follow-up of any transient alerts involving neutrinos or gamma-ray bursts, even those with poor spatial localization. We present the different facilities, tools, and methods we developed for this network and show its efficiency using observations of LIGO/Virgo S190425z, a binary neutron star merger candidate. We furthermore report on all GRANDMA follow-up observations performed during the first six months of the LIGO–Virgo observational campaign, and we derive constraints on the kilonova properties assuming that the events’ locations were imaged by our telescopes.

scholarly journals Probing binary neutron star mergers in dense environments using afterglow counterparts

2020 ◽  
Vol 639 ◽  
pp. A15
Author(s):  
Raphaël Duque ◽  
Paz Beniamini ◽  
Frédéric Daigne ◽  
Robert Mochkovitch
Keyword(s):  
Neutron Star ◽  
Gravitational Wave ◽  
Indirect Evidence ◽  
High Sensitivity ◽  
Small Sample ◽  
High Density ◽  
Binary Neutron Star ◽  
Delay Times ◽  
Wave Event

The only binary neutron star merger gravitational wave event with detected electromagnetic counterparts recorded to date is GRB170817A. This merger occurred in a rarefied medium with a density smaller than 10−3 − 10−2 cm−3. Since kicks are imparted to neutron star binaries upon formation, and due to their long delay times before merger, such low-density circum-merger media are generally expected. However, there is some indirect evidence for fast-merging or low-kick binaries, which would coalesce in denser environments. Nonetheless, present astronomical data are largely inconclusive on the possibility of these high-density mergers. We describe a method to directly probe this hypothetical population of high-density mergers through multi-messenger observations of binary neutron star merger afterglows, exploiting the high sensitivity of these signals to the density of the merger environment. This method is based on a sample of merger afterglows that has yet to be collected. Its constraining power is large, even with a small sample of events. We discuss the method’s limitations and applicability. In the upcoming era of third-generation gravitational wave detectors, this method’s potential will be fully realized as it will allow us to probe mergers that occurred soon after the peak of cosmic star formation, provided the follow-up campaigns are able to locate the sources.

scholarly journals Towards Improving the Prospects for Coordinated Gravitational-Wave and Electromagnetic Observations

2011 ◽  
Vol 7 (S285) ◽  
pp. 358-360 ◽  
Author(s):  
Ilya Mandel ◽  
Luke Z. Kelley ◽  
Enrico Ramirez-Ruiz
Keyword(s):  
Gravitational Wave ◽  
Prior Information ◽  
Gamma Ray ◽  
Optimal Parameter ◽  
Gamma Ray Bursts ◽  
Binary Neutron Star ◽  
Quantitative Estimates ◽  
Optimal Parameter Estimation ◽  
Parameter Estimation Techniques

AbstractWe discuss two approaches to searches for gravitational-wave (GW) and electromagnetic (EM) counterparts of binary neutron-star mergers. The first approach relies on triggering archival searches of GW detector data based on detections of EM transients. Quantitative estimates of the improvement to GW detector reach due to the increased confidence in the presence and parameters of a signal from a binary merger gained from the EM transient suggest utilizing other transients in addition to short gamma-ray bursts. The second approach involves following up GW candidates with targeted EM observations. We argue for the use of slower but optimal parameter-estimation techniques and for a more sophisticated use of astrophysical prior information, including galaxy catalogues to find preferred follow-up locations.

scholarly journals Using negative-latency gravitational wave alerts to detect prompt radio bursts from binary neutron star mergers with the Murchison Widefield Array

2019 ◽  
Vol 489 (1) ◽  
pp. L75-L79 ◽  
Author(s):  
Clancy W James ◽  
Gemma E Anderson ◽  
Linqing Wen ◽  
Joel Bosveld ◽  
Qi Chu ◽  
...  
Keyword(s):  
Neutron Star ◽  
Gravitational Wave ◽  
Radio Signal ◽  
Low Frequency ◽  
Positional Accuracy ◽  
Binary Neutron Star ◽  
Observational Mode ◽  
Fast Radio Burst ◽  
Murchison Widefield Array

ABSTRACT We examine how fast radio burst (FRB)-like signals predicted to be generated during the merger of a binary neutron star (BNS) may be detected in low-frequency radio observations triggered by the aLIGO/Virgo gravitational-wave detectors. The rapidity, directional accuracy, and sensitivity of follow-up observations with the Murchison Widefield Array (MWA) are considered. We show that with current methodology, the rapidity criterion fails for triggered MWA observations above 136 MHz for BNS mergers within the aLIGO/Virgo horizon, for which little dispersive delay is expected. A calculation of the expected reduction in response time by triggering on ‘negative latency’ alerts from aLIGO/Virgo observations of gravitational waves generated by the BNS inspiral is presented. This allows for observations up to 300 MHz where the radio signal is expected to be stronger. To compensate for the poor positional accuracy expected from these alerts, we propose a new MWA observational mode that is capable of viewing one-quarter of the sky. We show the sensitivity of this mode is sufficient to detect an FRB-like burst from an event similar to GW 170817 if it occurred during the ongoing aLIGO/Virgo third science run (O3).

scholarly journals Searching for electromagnetic counterparts to gravitational-wave merger events with the prototype Gravitational-Wave Optical Transient Observer (GOTO-4)

2020 ◽  
Vol 497 (1) ◽  
pp. 726-738 ◽  
Author(s):  
B P Gompertz ◽  
R Cutter ◽  
D Steeghs ◽  
D K Galloway ◽  
J Lyman ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Gamma Ray ◽  
Source Region ◽  
Binary Neutron Star ◽  
La Palma ◽  
Binary Black Hole ◽  
Test Models ◽  
Localization Performance ◽  
Optical Transient

ABSTRACT We report the results of optical follow-up observations of 29 gravitational-wave (GW) triggers during the first half of the LIGO–Virgo Collaboration (LVC) O3 run with the Gravitational-wave Optical Transient Observer (GOTO) in its prototype 4-telescope configuration (GOTO-4). While no viable electromagnetic (EM) counterpart candidate was identified, we estimate our 3D (volumetric) coverage using test light curves of on- and off-axis gamma-ray bursts and kilonovae. In cases where the source region was observable immediately, GOTO-4 was able to respond to a GW alert in less than a minute. The average time of first observation was 8.79 h after receiving an alert (9.90 h after trigger). A mean of 732.3 square degrees were tiled per event, representing on average 45.3 per cent of the LVC probability map, or 70.3 per cent of the observable probability. This coverage will further improve as the facility scales up alongside the localization performance of the evolving GW detector network. Even in its 4-telescope prototype configuration, GOTO is capable of detecting AT2017gfo-like kilonovae beyond 200 Mpc in favourable observing conditions. We cannot currently place meaningful EM limits on the population of distant ($\hat{D}_L = 1.3$ Gpc) binary black hole mergers because our test models are too faint to recover at this distance. However, as GOTO is upgraded towards its full 32-telescope, 2 node (La Palma & Australia) configuration, it is expected to be sufficiently sensitive to cover the predicted O4 binary neutron star merger volume, and will be able to respond to both northern and southern triggers.

scholarly journals Protomagnetar research through an analysis of the X-ray plateau in the multi-messengar era

2020 ◽  
Vol 641 ◽  
pp. A56
Author(s):  
Xiaoxiao Ren ◽  
Daming Wei ◽  
Zhenyu Zhu ◽  
Yan Yan ◽  
Chengming Li
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Gravitational Wave ◽  
Gamma Ray ◽  
Equations Of State ◽  
Electromagnetic Emission ◽  
Gamma Ray Bursts ◽  
Gamma Ray Burst ◽  
X Ray ◽  
Binary Neutron Star

The joint detection of the gravitational wave signal and the electromagnetic emission from a binary neutron star merger can place unprecedented constraint on the equation of state of supranuclear matter. Although a variety of electromagnetic counterparts have been observed for GW170817, including a short gamma-ray burst, kilonova, and the afterglow emission, the nature of the merger remnant is still unclear, however. The X-ray plateau is another important characteristics of short gamma-ray bursts. This plateau is probably due to the energy injection from a rapidly rotating magnetar. We investigate what we can learn from the detection of a gravitational wave along with the X-ray plateau. In principle, we can estimate the mass of the merger remnant if the X-ray plateau is caused by the central magnetar. We selected eight equations of state that all satisfy the constraint given by the gravitational wave observation, and then calculated the mass of the merger remnants of four short gamma-ray bursts with a well-measured X-ray plateau. If, on the other hand, the mass of the merger remnant can be obtained by gravitational wave information, then by comparing the masses derived by these two different methods can further constrain the equation of state. We discuss the possibility that the merger product is a quark star. In addition, we estimate the possible mass range for the recently discovered X-ray transient CDF-S XT2 that probably originated from a binary neutron star merger. Finally, under the assumption that the post-merger remnant of GW170817 was a supramassive neutron star, we estimated the allowed parameter space of the supramassive neutron star and find that in this case, the magnetic dipole radiation energy is so high that it may have some effects on the short gamma-ray burst and kilonova emission. The lack of detection of these effects suggests that the merger product of GW170817 may not be a supermassive neutron star.

The Electromagnetic Counterpart of the Gravitational Wave Source GW170817

2017 ◽  
Vol 14 (S339) ◽  
pp. 56-60
Author(s):  
T.-W. Chen
Keyword(s):  
Neutron Star ◽  
Gravitational Wave ◽  
Near Infrared ◽  
Direct Evidence ◽  
Gamma Ray ◽  
Infrared Imaging ◽  
Wave Source ◽  
Strong Source ◽  
Process Elements

AbstractOn 17th August 2017 a strong source of gravitational waves was detected by the LIGO-Virgo collaboration. The signal lasted for 60 seconds, and the event was followed just 2 seconds later by a short burst of gamma-rays that was detected by Fermi and INTEGRAL. The gravitational-wave and gamma-ray source had consistent sky positions to within about 30 square degrees. Within 10 hours of the gravitational-wave source event, a fast fading optical and near-infrared counterpart was discovered, which was subsequently followed-up and studied intensively for several weeks and months by numerous facilities. This talk presented the results from our optical and near-infrared imaging and spectroscopic follow-up campaign of this unprecedented discovery, which was the first electromagnetic counterpart of a gravitational-wave source, the first identification of a neutron star–neutron star merger, and the first direct evidence of the source of r-process elements. It focussed on the results of the GROND and ePESSTO teams, showing that this remarkable transient truly opened up the era of multi-messenger astronomy.

scholarly journals Binary Neutron Star and Short Gamma-Ray Burst Simulations in Light of GW170817

Galaxies ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 119 ◽  
Author(s):  
Antonios Nathanail
Keyword(s):  
Neutron Star ◽  
Gravitational Wave ◽  
Electromagnetic Radiation ◽  
Numerical Simulations ◽  
Gravitational Waves ◽  
Gamma Ray ◽  
Numerical Relativity ◽  
Gamma Ray Burst ◽  
Binary Neutron Star ◽  
The Status

In the dawn of the multi-messenger era of gravitational wave astronomy, which was marked by the first ever coincident detection of gravitational waves and electromagnetic radiation, it is important to take a step back and consider our current established knowledge. Numerical simulations of binary neutron star mergers and simulations of short GRB jets must combine efforts to understand such complicated and phenomenologically rich explosions. We review the status of numerical relativity simulations with respect to any jet or magnetized outflow produced after merger. We compare what is known from such simulations with what is used and obtained from short GRB jet simulations propagating through the BNS ejecta. We then review the established facts on this topic, as well as discuss things that need to be revised and further clarified.

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