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 Strategies for Finding Prompt Radio Counterparts to Gravitational Wave Transients with the Murchison Widefield Array

2016 ◽  
Vol 33 ◽  
Author(s):  
D. L. Kaplan ◽  
T. Murphy ◽  
A. Rowlinson ◽  
S. D. Croft ◽  
R. B. Wayth ◽  
...  
Keyword(s):  
Neutron Star ◽  
Radio Emission ◽  
Gravitational Wave ◽  
Radio Signal ◽  
Low Frequency ◽  
Field Of View ◽  
Optimal Conditions ◽  
Murchison Widefield Array ◽  
Complicated Geometry ◽  
Prompt Emission

AbstractWepresent and evaluate several strategies to search for prompt, low-frequency radio emission associated with gravitational wave transients using the Murchison Widefield Array. As we are able to repoint the Murchison Widefield Array on timescales of tens of seconds, we can search for the dispersed radio signal that has been predicted to originate along with or shortly after a neutron star-neutron star merger. We find that given the large, 600 deg2 instantaneous field of view of the Murchison Widefield Array, we can cover a significant fraction of the predicted gravitational wave error region, although due to the complicated geometry of the latter, we only cover > 50% of the error region for approximately 5% of events, and roughly 15% of events will be located < 10° from the Murchison Widefield Array pointing centre such that they will be covered in the radio images. For optimal conditions, our limiting flux density for a 10-s long transient would be 0.1 Jy, increasing to about 1 Jy for a wider range of events. This corresponds to luminosity limits of 1038−39 erg s−1 based on expectations for the distances of the gravitational wave transients, which should be sufficient to detect or significantly constrain a range of models for prompt emission.

scholarly journals LOFAR 144-MHz follow-up observations of GW170817

2020 ◽  
Vol 494 (4) ◽  
pp. 5110-5117
Author(s):  
J W Broderick ◽  
T W Shimwell ◽  
K Gourdji ◽  
A Rowlinson ◽  
S Nissanke ◽  
...  
Keyword(s):  
Neutron Star ◽  
Low Frequency ◽  
Radio Spectrum ◽  
Central Frequency ◽  
Binary Neutron Star ◽  
Upper Limit ◽  
Upper Limits ◽  
Maximum Elevation ◽  
Merger Event

ABSTRACT We present low-radio-frequency follow-up observations of AT 2017gfo, the electromagnetic counterpart of GW170817, which was the first binary neutron star merger to be detected by Advanced LIGO–Virgo. These data, with a central frequency of 144 MHz, were obtained with LOFAR, the Low-Frequency Array. The maximum elevation of the target is just 13${_{.}^{\circ}}$7 when observed with LOFAR, making our observations particularly challenging to calibrate and significantly limiting the achievable sensitivity. On time-scales of 130–138 and 371–374 d after the merger event, we obtain 3σ upper limits for the afterglow component of 6.6 and 19.5 mJy beam−1, respectively. Using our best upper limit and previously published, contemporaneous higher frequency radio data, we place a limit on any potential steepening of the radio spectrum between 610 and 144 MHz: the two-point spectral index $\alpha ^{610}_{144} \gtrsim$ −2.5. We also show that LOFAR can detect the afterglows of future binary neutron star merger events occurring at more favourable elevations.

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 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 Constraining coherent low-frequency radio flares from compact binary mergers

2019 ◽  
Vol 489 (3) ◽  
pp. 3316-3333 ◽  
Author(s):  
A Rowlinson ◽  
G E Anderson
Keyword(s):  
Neutron Star ◽  
Radio Emission ◽  
Gamma Ray ◽  
Low Frequency ◽  
Binary Neutron Star ◽  
Compact Binary ◽  
Binary Mergers ◽  
Wave Emission ◽  
Murchison Widefield Array ◽  
Response Modes

ABSTRACT The presence and detectability of coherent radio emission from compact binary mergers (containing at least one neutron star) remains poorly constrained due to large uncertainties in the models. These compact binary mergers may initially be detected as short gamma-ray bursts or via their gravitational wave emission. Several radio facilities have developed rapid response modes enabling them to trigger on these events and search for this emission. For this paper, we constrain this coherent radio emission using the deepest available constraints for GRB 150424A, which were obtained via a triggered observation with the Murchison Widefield Array. We then expand this analysis to determine the properties of magnetar merger remnants that may be formed via a general population of binary neutron star mergers. Our results demonstrate that many of the potential coherent emission mechanisms that have been proposed for such events can be detected or very tightly constrained by the complementary strategies used by the current generation of low-frequency radio telescopes.

scholarly journals GRANDMA observations of advanced LIGO’s and advanced Virgo’s third observational campaign

2020 ◽  
Vol 497 (4) ◽  
pp. 5518-5539 ◽  
Author(s):  
S Antier ◽  
S Agayeva ◽  
M Almualla ◽  
S Awiphan ◽  
A Baransky ◽  
...  
Keyword(s):  
Neutron Star ◽  
Gravitational Wave ◽  
Large Distance ◽  
Summary Statistics ◽  
Binary Neutron Star ◽  
Trigger Time ◽  
Coordination System ◽  
Total Coverage ◽  
Do So

ABSTRACT GRANDMA (Global Rapid Advanced Network Devoted to the Multi-messenger Addicts) is a network of 25 telescopes of different sizes, including both photometric and spectroscopic facilities. The network aims to coordinate follow-up observations of gravitational-wave (GW) candidate alerts, especially those with large localization uncertainties, to reduce the delay between the initial detection and the optical confirmation. In this paper, we detail GRANDMA’s observational performance during Advanced LIGO/Advanced Virgo Observing Run 3 (O3), focusing on the second part of O3; this includes summary statistics pertaining to coverage and possible astrophysical origin of the candidates. To do so, we quantify our observation efficiency in terms of delay between GW candidate trigger time, observations, and the total coverage. Using an optimized and robust coordination system, GRANDMA followed-up about 90 per cent of the GW candidate alerts, that is 49 out of 56 candidates. This led to coverage of over 9000 deg2 during O3. The delay between the GW candidate trigger and the first observation was below 1.5 h for 50 per cent of the alerts. We did not detect any electromagnetic counterparts to the GW candidates during O3, likely due to the very large localization areas (on average thousands of degrees squares) and relatively large distance of the candidates (above 200 Mpc for 60 per cent of binary neutron star, BNS candidates). We derive constraints on potential kilonova properties for two potential BNS coalescences (GW190425 and S200213t), assuming that the events’ locations were imaged.

scholarly journals DECAM-GROWTH SEARCH FOR THE FAINT AND DISTANT BINARY NEUTRON STAR AND NEUTRON STAR-BLACK HOLE MERGERS IN O3A

2021 ◽  
Vol 53 ◽  
pp. 91-99
Author(s):  
S. Anand ◽  
I. Andreoni ◽  
D. A. Goldstein ◽  
M. M. Kasliwal ◽  
T. Ahumada ◽  
...  
Keyword(s):  
Black Hole ◽  
Dark Energy ◽  
Neutron Star ◽  
Gravitational Wave ◽  
Web Application ◽  
Summary Statistics ◽  
Optical Counterpart ◽  
Binary Neutron Star ◽  
Complementary Role

Synoptic searches for the optical counterpart to a binary neutron star (BNS) or neutron star-black hole (NSBH) merger can pose significant challenges towards the discovery of kilonovae and performing multi-messenger science. In this work, we describe the advantage of a global multi-telescope network towards this end, with a particular focus on the key and complementary role the Dark Energy Camera (DECam) plays in multi-facility follow-up. We describe the Global Relay of Observatories Watching Transients Happen (GROWTH) Target-of-Opportunity (ToO) Marshal, a common web application we built to ingest events, plan observations, search for transient candidates, and retrieve performance summary statistics for all of the telescopes in our network. Our infrastructure enabled us to conduct observations of two events during O3a, S190426c and S190510g. Furthermore, our analysis of deep DECam observations of S190814bv conducted by the DESGW team, and access to a variety of global follow-up facilities allowed us to place meaningful constraints on the parameters of the kilonova and the merging binary. We emphasize the importance of a global telescope network in conjunction with a power telescope like DECam in performing searches for the counterparts to gravitational-wave sources.

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 The updated DESGW processing pipeline for the third LIGO/VIRGO observing run

2020 ◽  
Vol 245 ◽  
pp. 01008
Author(s):  
Kenneth Herner ◽  
James Annis ◽  
Alyssa Garcia ◽  
Marcelle Soares-Santos ◽  
Dillon Brout ◽  
...  
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Gravitational Wave ◽  
Data Transfer ◽  
Rapid Identification ◽  
Binary Neutron Star ◽  
Performance Improvements ◽  
Processing Pipeline ◽  
Difference Imaging

The DESGW group seeks to identify electromagnetic counterparts of gravitational wave events seen by the LIGO-VIRGO network, such as those expected from binary neutron star mergers or neutron star-black hole mergers. DESGW was active throughout the first two LIGO observing seasons, following up several binary black hole mergers and the first binary neutron star merger, GW170817. This work describes the modifications to the observing strategy generation and image processing pipeline between the second (ending in August 2017) and third (beginning in April 2019) LIGO observing seasons. The modifications include a more robust observing strategy generator, further parallelization of the image reduction software and difference imaging processing pipeline, data transfer streamlining, and a web page listing identified counterpart candidates that updates in real time. Taken together, the additional parallelization steps enable the identification of potential electromagnetic counterparts within fully calibrated search images in less than one hour, compared to the 3-5 hours it would typically take during the first two seasons. These performance improvements are critical to the entire EM follow-up community, as rapid identification (or rejection) of candidates enables detailed and rapid spectroscopic follow-up by multiple instruments, leading to more information about the environment immediately following such gravitational wave events.

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