A comparison of period finding algorithms

Graham, M. J.; Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Donalek, C.; Duan, Victor; Maker, Allison

doi:10.1093/mnras/stt1264

Cited by 98 publications

(101 citation statements)

References 61 publications

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“…The AFD technique improves the selection by comparing Fourier fits to the five best periods found by LS along with five periods from each of regular bin Analysis of Variance (AoV) and multiharmonic AoV (Schwarzenberg-Czerny 1996). In this process, we used multiple period-finding techniques since the accuracy and completeness of each method varies significantly depending on the type of variability and sampling (Graham et al 2013). The combination of three different period-finding techniques increases the chance of finding the true period and provides confidence when a common period is found with multiple different techniques.…”

Section: Selection Of Periodic Variablesmentioning

confidence: 99%

The Catalina Surveys Southern periodic variable star catalogue

Drake

Djorgovski

Catelan

et al. 2017

Monthly Notices of the Royal Astronomical Society

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167

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Here, we present the results from our analysis of 6 yr of optical photometry taken by the Siding Spring Survey (SSS). This completes a search for periodic variable stars within the 30 000 deg 2 of the sky covered by the Catalina Surveys. The current analysis covers 81 million sources with declinations between −20 • and −75 • with median magnitudes in the range 11 < V < 19.5. We find approximately 34 000 new periodic variable stars in addition to the ∼9000 RR Lyrae that we previously discovered in SSS data. This brings the total number of periodic variables identified in Catalina data to ∼110 000. The new SSS periodic variable stars mainly consist of eclipsing binaries, RR Lyrae, LPVs, RS CVn stars, δ Scutis, and Anomalous Cepheids. By cross-matching these variable stars with those from prior surveys, we find that ∼90 per cent of the sources are new discoveries and recover ∼95 per cent of the known periodic variables in the survey region. For the known sources, we find excellent agreement between our catalogue and prior values of luminosity, period, and amplitude. However, we find many variable stars that had previously been misclassified. Examining the distribution of RR Lyrae, we find a population associated with the Large Magellanic Cloud (LMC) that extends more than 20 • from its centre confirming recent evidence for the existence of a very extended stellar halo in the LMC. By combining SSS photometry with Dark Energy Survey data, we identify additional LMC halo RR Lyrae, thus confirming the significance of the population.

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Section: Selection Of Periodic Variablesmentioning

confidence: 99%

The Catalina Surveys Southern periodic variable star catalogue

Drake

Djorgovski

Catelan

et al. 2017

Monthly Notices of the Royal Astronomical Society

Self Cite

167

133

View full text Add to dashboard Cite

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“…These circumstances have limited the usage of ANOVA in microvariability studies, even if it is a robust and powerful statistical procedure that has been employed for decades in other related areas, and particularly in periodicity studies on folded light-curves of variable stars (e.g. Schwarzenberg-Czerny 1989, 1996Woniak et al 2004;Graham et al 2013). …”

Section: Introductionmentioning

confidence: 99%

On the Reliability of Microvariability Tests in Quasars

Diego

2014

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Microvariations probe the physics and internal structure of quasars. Unpredictability and small flux variations make this phenomenon elusive and difficult to detect. Variance based probes such as the C and F tests, or a combination of both, are popular methods to compare the light-curves of the quasar and a comparison star. Recently, detection claims in some studies depend on the agreement of the results of the C and F tests, or of two instances of the F -test, in rejecting the non-variation null hypothesis. However, the C-test is a non-reliable statistical procedure, the F -test is not robust, and the combination of tests with concurrent results is anything but a straightforward methodology. A priori Power Analysis calculations and post hoc analysis of Monte-Carlo simulations show excellent agreement for the Analysis of Variance test to detect microvariations, as well as the limitations of the F -test. Additionally, combined tests yield correlated probabilities that make the assessment of statistical significance unworkable. However, it is possible to include data from several field stars to enhance the power in a single Ftest, increasing the reliability of the statistical analysis. This would be the preferred methodology when several comparison stars are available. An example using two stars and the enhanced Ftest is presented. These results show the importance of using adequate methodologies, and avoid inappropriate procedures that can jeopardize microvariability detections. Power analysis and Monte-Carlo simulations are useful tools for research planning, as they can reveal the robustness and reliability of different research approaches.

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“…• The LS and GLS have been used to extract periodic features from light curves for the classification of variable stars (Richards et al 2011;Graham et al 2013). To improve the classification of variable stars, the BFP/MLP can be calculated for a given light curve in order to account for the red noise, which is found to be common in various light curves (Pont et al 2006;Aigrain et al 2015).…”

Section: Discussionmentioning

confidence: 99%

Agatha: disentangling periodic signals from correlated noise in a periodogram framework

Feng

Tuomi

Jones

2017

Monthly Notices of the Royal Astronomical Society

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Periodograms are used as a key significance assessment and visualisation tool to display the significant periodicities in unevenly sampled time series. We introduce a framework of periodograms, called "Agatha", to disentangle periodic signals from correlated noise and to solve the 2-dimensional model selection problem: signal dimension and noise model dimension. These periodograms are calculated by applying likelihood maximization and marginalization and combined in a self-consistent way. We compare Agatha with other periodograms for the detection of Keplerian signals in synthetic radial velocity data produced for the Radial Velocity Challenge as well as in radial velocity datasets of several Sun-like stars. In our tests we find Agatha is able to recover signals to the adopted detection limit of the radial velocity challenge. Applied to real radial velocity, we use Agatha to confirm previous analysis of CoRoT-7 and to find two new planet candidates with minimum masses of 15.1 M ⊕ and 7.08 M ⊕ orbiting HD177565 and HD41248, with periods of 44.5 d and 13.4 d, respectively. We find that Agatha outperforms other periodograms in terms of removing correlated noise and assessing the significances of signals with more robust metrics. Moreover, it can be used to select the optimal noise model and to test the consistency of signals in time. Agatha is intended to be flexible enough to be applied to time series analyses in other astronomical and scientific disciplines. Agatha is available at http://www.agatha.herts.ac.uk.

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A comparison of period finding algorithms

Cited by 98 publications

References 61 publications

The Catalina Surveys Southern periodic variable star catalogue

The Catalina Surveys Southern periodic variable star catalogue

On the Reliability of Microvariability Tests in Quasars

Agatha: disentangling periodic signals from correlated noise in a periodogram framework

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