One parameter binary black hole inverse problem using a sparse training set

2018 ◽  
Vol 27 (04) ◽  
pp. 1850043 ◽  
Author(s):  
M. Carrillo ◽  
M. Gracia-Linares ◽  
J. A. González ◽  
F. S. Guzmán
Keyword(s):  
Black Hole ◽  
Time Domain ◽  
Signal To Noise Ratio ◽  
Small Sample ◽  
Mass Ratio ◽  
Training Set ◽  
The Core ◽  
Binary Black Hole ◽  
Orbital Phase ◽  
The Time Domain

In this paper, we use Artificial Neural Networks (ANNs) to estimate the mass ratio [Formula: see text] in a binary black hole collision out of the gravitational wave (GW) strain. We assume the strain is a time series (TS) that contains a part of the orbital phase and the ring-down of the final black hole. We apply the method to the strain itself in the time domain and also in the frequency domain. We present the accuracy in the prediction of the ANNs trained with various values of signal-to-noise ratio (SNR). The core of our results is that the estimate of the mass ratio is obtained with a small sample of training signals and resulting in predictions with errors of the order of 1% for our best ANN configurations.

scholarly journals The Radio Jet in 3C418

1984 ◽  
Vol 110 ◽  
pp. 141-143 ◽  
Author(s):  
T.W.B. Muxlow ◽  
M. Jullian ◽  
R. Linfield
Keyword(s):  
Black Hole ◽  
Cone Angle ◽  
The Other ◽  
Simple Solution ◽  
Close Binary ◽  
Radio Structure ◽  
The Core ◽  
Binary Black Hole ◽  
Model Geometry

Models are here presented interpreting the arcsecond radio structure found in the quasar 3C418 as a precessing jet. No simple solution exists and it has been found necessary to complicate the model geometry by allowing the precession cone-angle to increase with time. The timescales suggest the presence of a close binary black-hole system within the quasar core. The modelled behaviour of the precession cone close to the core is explained either by interaction of the jet with the surrounding galactic material or by the observation of the source during the capture of one black-hole by the other.

scholarly journals A SFTD Algorithm for Optimizing the Performance of the Readout Strategy of Residence Time Difference Fluxgate

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3985 ◽  
Author(s):  
Siyu Chen ◽  
Yanzhang Wang ◽  
Jun Lin
Keyword(s):  
Residence Time ◽  
Time Domain ◽  
Signal To Noise Ratio ◽  
Low Frequency ◽  
Transformation Method ◽  
Time Difference ◽  
Single Frequency ◽  
Time Frequency ◽  
Frequency Magnetic Field ◽  
The Time Domain

Residence time difference (RTD) fluxgate sensor is a potential device to measure the DC or low-frequency magnetic field in the time domain. Nevertheless, jitter noise and magnetic noise severely affect the detection result. A novel post-processing algorithm for jitter noise reduction of RTD fluxgate output strategy based on the single-frequency time difference (SFTD) method is proposed in this study to boost the performance of the RTD system. This algorithm extracts the signal that has a fixed frequency and preserves its time-domain information via a time–frequency transformation method. Thereby, the single-frequency signal without jitter noise, which still contains the ambient field information in its time difference, is yielded. Consequently, compared with the traditional comparator RTD method (CRTD), the stability of the RTD estimation (in other words, the signal-to-noise ratio of residence time difference) has been significantly boosted with sensitivity of 4.3 μs/nT. Furthermore, the experimental results reveal that the RTD fluxgate is comparable to harmonic fluxgate sensors, in terms of noise floor.

Smoothing imaging condition for shot-profile migration

Geophysics ◽  
2007 ◽  
Vol 72 (3) ◽  
pp. S149-S154 ◽  
Author(s):  
Antoine Guitton ◽  
Alejandro Valenciano ◽  
Dimitri Bevc ◽  
Jon Claerbout
Keyword(s):  
Time Domain ◽  
Signal To Noise Ratio ◽  
Wiener Filter ◽  
Window Size ◽  
Trial And Error ◽  
Data Set ◽  
Smoothing Operator ◽  
Imaging Condition ◽  
Damping Parameter ◽  
The Time Domain

Amplitudes in shot-profile migration can be improved if the imaging condition incorporates a division (deconvolution in the time domain) of the upgoing wavefield by the downgoing wavefield. This division can be enhanced by introducing an optimal Wiener filter which assumes that the noise present in the data has a white spectrum. This assumption requires a damping parameter, related to the signal-to-noise ratio, often chosen by trial and error. In practice, the damping parameter replaces the small values of the spectrum of the downgoing wavefield and avoids division by zero. The migration results can be quite sensitive to the damping parameter, and in most applications, the upgoing and downgoing wavefields are simply multiplied. Alternatively, the division can be made stable by filling the small values of thespectrum with an average of the neighboring points. This averaging is obtained by running a smoothing operator on the spectrum of the downgoing wavefield. This operation called the smoothing imaging condition. Our results show that where the spectrum of the downgoing wavefield is high, the imaging condition with damping and smoothing yields similar results, thus correcting for illumination effects. Where the spectrum is low, the smoothing imaging condition tends to be more robust to the noise level present in the data, thus giving better images than the imaging condition with damping. In addition, our experiments indicate that the parameterization of the smoothing imaging condition, i.e., choice of window size for the smoothing operator, is easy and repeatable from one data set to another, making it a valuable addition to our imaging toolbox.

scholarly journals The Eccentric and Accelerating Stellar Binary Black Hole Mergers in Galactic Nuclei: Observing in Ground and Space Gravitational-wave Observatories

2021 ◽  
Vol 923 (2) ◽  
pp. 139
Author(s):  
Fupeng Zhang ◽  
Xian Chen ◽  
Lijing Shao ◽  
Kohei Inayoshi
Keyword(s):  
Black Hole ◽  
Gravitational Wave ◽  
Signal To Noise Ratio ◽  
Galactic Nuclei ◽  
Signal To Noise ◽  
High Eccentricity ◽  
Massive Black Hole ◽  
Binary Black Holes ◽  
Binary Black Hole ◽  
Space Observatories

Abstract We study the stellar binary black holes (BBHs) inspiraling/merging in galactic nuclei based on our numerical method GNC. We find that 3%–40% of all newborn BBHs will finally merge due to various dynamical effects. In a five-year mission, up to 104, 105, and ∼100 of BBHs inspiraling/merging in galactic nuclei can be detected with signal-to-noise ration >8 in Advanced LIGO (aLIGO), Einstein/DECIGO, and TianQin/LISA/TaiJi, respectively. Roughly tens are detectable in both LISA/TaiJi/TianQin and aLIGO. These BBHs have two unique characteristics. (1) Significant eccentricities: 1%–3%, 2%–7%, or 30%–90% of them have e i > 0.1 when they enter into aLIGO, Einstein, or space observatories, respectively. Such high eccentricities provide a possible explanation for that of GW190521. Most highly eccentric BBHs are not detectable in LISA/Tianqin/TaiJi before entering into aLIGO/Einstein, as their strain becomes significant only at f GW ≳ 0.1 Hz. DECIGO becomes an ideal observatory to detect those events, as it can fully cover the rising phase. (2) Up to 2% of BBHs can inspiral/merge at distances ≲103 r SW from the massive black hole, with significant accelerations, such that the Doppler phase drift of ∼10–105 of them can be detected with signal-to-noise ratio >8 in space observatories. The energy density of the gravitational-wave backgrounds (GWBs) contributed by these BBHs deviates from the power-law slope of 2/3 at f GW ≲ 1 mHz. The high eccentricity, significant accelerations, and the different profile of the GWB of these sources make them distinguishable, and thus interesting for future gravitational-wave detections and tests of relativities.

scholarly journals BINARY BLACK HOLE MERGER WAVEFORMS IN THE EXTREME MASS RATIO LIMIT

2008 ◽  
Author(s):  
THIBAULT DAMOUR ◽  
ALESSANDRO NAGAR
Keyword(s):  
Black Hole ◽  
Mass Ratio ◽  
Binary Black Hole ◽  
Ratio Limit

scholarly journals Upper limits on the temperature of inspiraling astrophysical black holes

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Adrian Ka-Wai Chung ◽  
Mairi Sakellariadou
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Wave ◽  
Binary Black Hole ◽  
Upper Limits ◽  
Gravity Effects ◽  
Wave Event ◽  
Orbital Phase ◽  
Intrinsic Radiation ◽  
Peak Luminosity

AbstractWe present a method to constrain the temperature of astrophysical black holes through detecting the inspiral phase of binary black hole coalescences. At sufficient separation, inspiraling black holes can be regarded as isolated objects, hence their temperature can still be defined. Due to their intrinsic radiation, inspiraling black holes lose part of their masses during the inspiral phase. As a result, coalescence speeds up, introducing a correction to the orbital phase. We show that this dephasing may allow us to constrain the temperature of inspiraling black holes through gravitational-wave detection. Using the binary black-hole coalescences of the first two observing runs of the Advanced LIGO and Virgo detectors, we constrain the temperature of parental black holes to be less than about $$ 10^9 $$ 10 9  K. Such a constraint corresponds to luminosity of about $$ 10^{-16} M_{\odot }~\mathrm{s}^{-1} $$ 10 - 16 M ⊙ s - 1 for a black hole of $$ 20 M_{\odot } $$ 20 M ⊙ , which is about 20 orders of magnitude below the peak luminosity of the corresponding gravitational-wave event, indicating no evidence for strong quantum-gravity effects through the detection of the inspiral phase.

scholarly journals An Adaptive Spectral Kurtosis Method Based on Optimal Filter

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Yanli Yang ◽  
Ting Yu
Keyword(s):  
Fault Diagnosis ◽  
Frequency Domain ◽  
Time Domain ◽  
Experimental Results ◽  
Bearing Fault ◽  
Spectral Kurtosis ◽  
Bearing Fault Diagnosis ◽  
The Core ◽  
Factors Influencing ◽  
The Time Domain

As a useful tool to detect protrusion buried in signals, kurtosis has a wide application in engineering, for example, in bearing fault diagnosis. Spectral kurtosis (SK) can further indicate the presence of a series of transients and their locations in the frequency domain. The factors influencing kurtosis values are first analyzed, leading to the conclusion that amplitude, not the frequency of signals, and noise make major contribution to kurtosis values. It is helpful to detect impulsive components if the components with big amplitude are removed from composite signals. Based on this cognition, an adaptive SK algorithm is proposed in this paper. The core steps of the proposed SK algorithm are to find maxima, add window around maxima, merge windows in the frequency domain, and then filter signals according to the merged window in the time domain. The parameters of the proposed SK algorithm are varying adaptively with signals. Some experimental results are presented to demonstrate the effectiveness of the proposed algorithm.

scholarly journals Simultaneous Dual-mode Emission and Tunable Multicolor in the Time Domain from Lanthanide-doped Core-shell Microcrystals

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1023 ◽  
Author(s):  
Dandan Ju ◽  
Feng Song ◽  
Adnan Khan ◽  
Feifei Song ◽  
Aihua Zhou ◽  
...  
Keyword(s):  
Time Domain ◽  
Near Infrared ◽  
Core Shell ◽  
Dual Mode ◽  
Time Resolved ◽  
Excitation Light ◽  
The Core ◽  
Surface Quenching ◽  
The Time Domain ◽  
High Level

The dual-mode emission and multicolor outputs in the time domain from core-shell microcrystals are presented. The core-shell microcrystals, with NaYF4:Yb/Er as the core and NaYF4:Ce/Tb/Eu as the shell, were successfully fabricated by employing the hydrothermal method, which confines the activator ions into a separate region and minimizes the effect of surface quenching. The material is capable of both upconversion and downshifting emission, and their multicolor outputs in response to 980 nm near-infrared (NIR) excitation laser and 252 nm, and 395 nm ultraviolet (UV) excitation light have been investigated. Furthermore, the tunable color emissions by controlling the Tb3+- Eu3+ ratio in shells and the energy transfer of Ce3+→Tb3+→ Eu3+ were discussed in details. In addition, color tuning of core-shell-structured microrods from green to red region in the time domain could be obtained by setting suitable delay time. Due to downshifting multicolor outputs (time-resolved and pump-wavelength-induced downshifting) coupled with the upconversion mode, the core-shell microrods can be potentially applied to displays and high-level security.

scholarly journals Binary black hole merger gravitational waves and recoil in the large mass ratio limit

2010 ◽  
Vol 81 (10) ◽  
Author(s):  
Pranesh A. Sundararajan ◽  
Gaurav Khanna ◽  
Scott A. Hughes
Keyword(s):  
Black Hole ◽  
Gravitational Waves ◽  
Large Mass ◽  
Mass Ratio ◽  
Binary Black Hole ◽  
Ratio Limit ◽  
Large Mass Ratio

scholarly journals Binary black hole merger in the extreme-mass-ratio limit

2007 ◽  
Vol 24 (12) ◽  
pp. S109-S123 ◽  
Author(s):  
Alessandro Nagar ◽  
Thibault Damour ◽  
Angelo Tartaglia
Keyword(s):  
Black Hole ◽  
Mass Ratio ◽  
Binary Black Hole ◽  
Ratio Limit
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