scholarly journals AGILE Observations of the LIGO-Virgo Gravitational-wave Events of the GWTC-1 Catalog

2022 ◽  
Vol 924 (2) ◽  
pp. 80
Author(s):  
A. Ursi ◽  
F. Verrecchia ◽  
G. Piano ◽  
C. Casentini ◽  
M. Tavani ◽  
...  
Keyword(s):  
Energy Range ◽  
Gravitational Wave ◽  
Gamma Ray ◽  
Time Window ◽  
Time Frame ◽  
Upper Limit ◽  
Agile Satellite ◽  
Credible Region ◽  
Soft Spectrum

Abstract We present a comprehensive review of AGILE follow-up observations of the Gravitational Wave (GW) events and the unconfirmed marginal triggers reported in the first LIGO-Virgo (LV) Gravitational Wave Transient Catalog (GWTC-1). For seven GW events and 13 LV triggers, the associated 90% credible region was partially or fully accessible to the AGILE satellite at the T 0; for the remaining events, the localization region was not accessible to AGILE due to passages into the South Atlantic Anomaly, or complete Earth occultations (as in the case of GW170817). A systematic search for associated transients, performed on different timescales and on different time intervals about each event, led to the detection of no gamma-ray counterparts. We report AGILE MCAL upper limit fluences in the 400 keV–100 MeV energy range, evaluated in a time window of T 0 ± 50 s around each event, as well as AGILE GRID upper limit (UL) fluxes in the 30 MeV–50 GeV energy range, evaluated in a time frame of T 0 ± 950 s around each event. All ULs are estimated at different integration times and are evaluated within the portions of GW credible region accessible to AGILE at the different times under consideration. We also discuss the possibility of AGILE MCAL to trigger and detect a weak soft-spectrum burst such as GRB 170817A.

scholarly journals Search for UHE neutrinos in coincidence with LIGO GW150914 event with the Pierre Auger Observatory

2016 ◽  
Vol 12 (S324) ◽  
pp. 295-298
Author(s):  
Lili Yang ◽  
Keyword(s):  
Energy Range ◽  
Gravitational Wave ◽  
High Energy ◽  
Universal Time ◽  
Pierre Auger Observatory ◽  
Ultra High Energy ◽  
Upper Limit ◽  
Surface Detector ◽  
High Energy Regime

AbstractThe first gravitational wave transient GW150914 was observed by Advanced LIGO on September 14th, 2015 at 09:50:45 Universal Time. In addition to follow-up electromagnetic observations, the detection of neutrinos will probe deeply and more on the nature of astrophysical sources, especially in the ultra-high energy regime. Neutrinos in the EeV energy range were searched in data collected at the surface detector of the Pierre Auger Observatory within ± 500 s and 1 day after the GW150914 event. No neutrino candidates were found. Based on this non-observation, we derive the first and only neutrino fluence upper limit at EeV energies for this event at 90% CL, and report constraints on existence of accretion disk around mergers.

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 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 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 Gravitational-wave follow-up with CTA after the detection of GRBs in the TeV energy domain

2019 ◽  
Vol 490 (3) ◽  
pp. 3476-3482 ◽  
Author(s):  
I Bartos ◽  
K R Corley ◽  
N Gupte ◽  
N Ash ◽  
Z Márka ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Gamma Ray ◽  
The United States ◽  
High Energy ◽  
Cherenkov Telescopes ◽  
Wave Event ◽  
Energy Domain ◽  
Time Requirements ◽  
High Energy Emission

ABSTRACT The recent discovery of TeV emission from gamma-ray bursts (GRBs) by the MAGIC and H.E.S.S. Cherenkov telescopes confirmed that emission from these transients can extend to very high energies. The TeV energy domain reaches the most sensitive band of the Cherenkov Telescope Array (CTA). This newly anticipated, improved sensitivity will enhance the prospects of gravitational-wave follow-up observations by CTA to probe particle acceleration and high-energy emission from binary black hole and neutron star mergers, and stellar core-collapse events. Here we discuss the implications of TeV emission on the most promising strategies of choice for the gravitational-wave follow-up effort for CTA and Cherenkov telescopes more broadly. We find that TeV emission (i) may allow more than an hour of delay between the gravitational-wave event and the start of CTA observations; (ii) enables the use of CTA’s small size telescopes that have the largest field of view. We characterize the number of pointings needed to find a counterpart. (iii) We compute the annual follow-up time requirements and find that prioritization will be needed. (iv) Even a few telescopes could detect sufficiently nearby counterparts, raising the possibility of adding a handful of small-sized or medium-sized telescopes to the network at diverse geographic locations. (v) The continued operation of VERITAS/H.E.S.S./MAGIC would be a useful compliment to CTA’s follow-up capabilities by increasing the sky area that can be rapidly covered, especially in the United States and Australia, in which the present network of gravitational-wave detectors is more sensitive.

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 Black-hole–Neutron-star Mergers Are Unlikely Multimessenger Sources

2021 ◽  
Vol 923 (1) ◽  
pp. L2
Author(s):  
Giacomo Fragione
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Equation Of State ◽  
Gravitational Wave ◽  
Internal Structure ◽  
Binary Stars ◽  
Statistical Study ◽  
Gamma Ray ◽  
High Rate ◽  
Upper Limit

Abstract The promise by the LIGO/Virgo/Kagra (LVK) collaboration to detect black-hole–neutron-star (BH–NS) mergers via gravitational wave (GW) emission has recently been fulfilled with the detection of GW200105 and GW200115. Mergers of BH–NS binaries are particularly exciting for their multimessenger potential since GW detection can be followed by an electromagnetic (EM) counterpart (kilonova, gamma-ray burst, afterglow) that can reveal important information on the equation of state (EOS) of NSs and the nature of the BH spin. This can happen whenever the NS does not directly plunge into the BH, but rather is tidally disrupted, leaving behind debris to accrete. We carry out a statistical study of the binary stars that evolve to form a BH–NS binary and compute the rate of merger events that can be followed by an EM counterpart. We find that ≳50% of the mergers can lead to an EM counterpart only in the case where BHs are born highly spinning (χ BH ≳ 0.7), while this fraction does not exceed about 30% for stiff NS EOSs and a few percent for soft NS EOSs for low-spinning BHs (χ BH ≲ 0.2), suggesting that a high rate of EM counterparts of BH–NS would provide support for high natal BH spins. However, the possibilities that BHs are born with near-maximal spins and that NS internal structure is described by a stiff EOS are disfavored by current LVK constraints. Considering that these values only represent an upper limit to observe an EM counterpart due to current observational limitations, such as brightness sensitivity and sky localization, BH–NS mergers are unlikely multimessenger sources.

scholarly journals Optimizing Cadences with Realistic Light-curve Filtering for Serendipitous Kilonova Discovery with Vera Rubin Observatory

2021 ◽  
Vol 258 (1) ◽  
pp. 5
Author(s):  
Igor Andreoni ◽  
Michael W. Coughlin ◽  
Mouza Almualla ◽  
Eric C. Bellm ◽  
Federica B. Bianco ◽  
...  
Keyword(s):  
Near Infrared ◽  
Gamma Ray ◽  
Time Frame ◽  
High Energy ◽  
Wide Field ◽  
Field Surveys ◽  
Deep Survey ◽  
Energy Gamma ◽  
Further Development

Abstract Current and future optical and near-infrared wide-field surveys have the potential to find kilonovae, the optical and infrared counterparts to neutron star mergers, independently of gravitational-wave or high-energy gamma-ray burst triggers. The ability to discover fast and faint transients such as kilonovae largely depends on the area observed, the depth of those observations, the number of revisits per field in a given time frame, and the filters adopted by the survey; it also depends on the ability to perform rapid follow-up observations to confirm the nature of the transients. In this work, we assess kilonova detectability in existing simulations of the Legacy Survey of Space and Time strategy for the Vera C. Rubin Wide Fast Deep survey, with focus on comparing rolling to baseline cadences. Although currently available cadences can enable the detection of >300 kilonovae out to ∼1400 Mpc over the 10 year survey, we can expect only 3–32 kilonovae similar to GW170817 to be recognizable as fast-evolving transients. We also explore the detectability of kilonovae over the plausible parameter space, focusing on viewing angle and ejecta masses. We find that observations in redder izy bands are crucial for identification of nearby (within 300 Mpc) kilonovae that could be spectroscopically classified more easily than more distant sources. Rubin’s potential for serendipitous kilonova discovery could be increased by gain of efficiency with the employment of individual 30 s exposures (as opposed to 2 × 15 s snap pairs), with the addition of red-band observations coupled with same-night observations in g or r bands, and possibly with further development of a new rolling-cadence strategy.

Sign in / Sign up

Export Citation Format

Share Document