Garret Cotter: Publications

Deviations from normal distributions in artificial and real time series: a false positive prescription

Monthly Notices of the Royal Astronomical Society Oxford University Press 489:2 (2019) 2117-2129

Authors:

Paul Morris, N Chakraborty, G Cotter

Abstract:

ABSTRACT Time-series analysis allows for the determination of the Power Spectral Density (PSD) and Probability Density Function (PDF) for astrophysical sources. The former of these illustrates the distribution of power at various time-scales, typically taking a power-law form, while the latter characterizes the distribution of the underlying stochastic physical processes, with Gaussian and lognormal functional forms both physically motivated. In this paper, we use artificial time series generated using the prescription of Timmer & Koenig to investigate connections between the PDF and PSD. PDFs calculated for these artificial light curves are less likely to be well described by a Gaussian functional form for steep (Γ⪆1) PSD indices due to weak non-stationarity. Using the Fermi LAT monthly light curve of the blazar PKS2155-304 as an example, we prescribe and calculate a false positive rate that indicates how likely the PDF is to be attributed an incorrect functional form. Here, we generate large numbers of artificial light curves with intrinsically normally distributed PDFs and with statistical properties consistent with observations. These are used to evaluate the probabilities that either Gaussian or lognormal functional forms better describe the PDF. We use this prescription to show that PKS2155-304 requires a high prior probability of having a normally distributed PDF, $P(\rm {G})~$ ≥ 0.82, for the calculated PDF to prefer a Gaussian functional form over a lognormal. We present possible choices of prior and evaluate the probability that PKS2155-304 has a lognormally distributed PDF for each.

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Deviations from normal distributions in artificial and real time series: a false positive prescription

(2019)

Authors:

Paul J Morris, Nachiketa Chakraborty, Garret Cotter

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Prospects for the Use of Photosensor Timing Information with Machine Learning Techniques in Background Rejection.

Sissa Medialab Srl (2019) 798

Authors:

Samuel Timothy Spencer, Thomas Armstrong, Jason John Watson, Garret Cotter

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Prospects for the Use of Photosensor Timing Information with Machine Learning Techniques in Background Rejection

(2019)

Authors:

Samuel Spencer, Thomas Armstrong, Jason Watson, Garret Cotter

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The feasibility of magnetic reconnection powered blazar flares from synchrotron self-Compton emission

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 486:2 (2019) 1548-1562

Authors:

Paul J Morris, William J Potter, Garret Cotter

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Garret Cotter

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Deviations from normal distributions in artificial and real time series: a false positive prescription

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Deviations from normal distributions in artificial and real time series: a false positive prescription

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Prospects for the Use of Photosensor Timing Information with Machine Learning Techniques in Background Rejection.

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Prospects for the Use of Photosensor Timing Information with Machine Learning Techniques in Background Rejection

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The feasibility of magnetic reconnection powered blazar flares from synchrotron self-Compton emission

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Deviations from normal distributions in artificial and real time series: a false positive prescription

Authors:

Abstract:

Deviations from normal distributions in artificial and real time series: a false positive prescription

Authors:

Prospects for the Use of Photosensor Timing Information with Machine Learning Techniques in Background Rejection.

Authors:

Prospects for the Use of Photosensor Timing Information with Machine Learning Techniques in Background Rejection

Authors:

The feasibility of magnetic reconnection powered blazar flares from synchrotron self-Compton emission

Authors: