The TAOS Project: High-Speed Crowded Field Aperture Photometry

Zhang, Z.-W.; Kim, Dae Won; Wang, J.-H.; Lehner, M. J.; Chen, W. P.; Byun, Yong Ik; Alcock, C.; Axelrod, T. S.; Bianco, Federica; Coehlo, N. K.; Cook, K. H.; Dave, R.; Pater, Imke de; Giammarco, J.; King, S. K.; Lee, T.; Lin, Hai Chun; Marshall, Stuart; Porrata, R.; Protopapas, Pavlos; Rice, John A.; Schwamb, Megan E.; Wang, S.-Y.; Wen, C. Y.

doi:10.1086/649507

Cited by 9 publications

(4 citation statements)

References 5 publications

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“…Furthermore, we have developed a method to test for widespread dependence between lightcurves in a data run, which allows us to reject runs with inherent characteristics which could possibly give rise to a larger false positive rates. We note that while the method described in this paper is sufficient for the calculation of the rate of false positive events that arise due to random statistical chance, it is not capable of estimating the background event rate due to systematic errors in the TAOS photometry (Zhang et al 2009). For example, tracking errors or moving objects in the images could give rise to false detections in the data set.…”

Section: Resultsmentioning

confidence: 95%

“…Due to the fact that any correlations in the data may not show up in lightcurves with low SNR values, we perform the diagnostic tests only on those lightcurve sets with SNR ≥ 10. Details of the algorithm used to calculate SNR values of our lightcurves are given in Zhang et al (2009). To summarize, we first calculate a 5σ-clipped rolling mean similar to that which is calculated in the mean filter, and then average the value of the rolling mean to get the signal.…”

Section: Application Of Diagnostic Statisticsmentioning

confidence: 99%

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The TAOS Project: Statistical Analysis of Multi-Telescope Time Series Data

Lehner

Coehlo

Zhang

et al. 2010

PUBL ASTRON SOC PAC

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ABSTRACT. The Taiwanese-American Occultation Survey (TAOS) monitors fields of up to ∼1000 stars at 5 Hz simultaneously with four small telescopes to detect occultation events from small (∼1 km) Kuiper Belt Objects (KBOs). The survey presents a number of challenges, in particular the fact that the occultation events we are searching for are extremely rare and are typically manifested as slight flux drops for only one or two consecutive time series measurements. We have developed a statistical analysis technique to search the multi-telescope data set for simultaneous flux drops which provides a robust false-positive rejection and calculation of event significance. In this article, we describe in detail this statistical technique and its application to the TAOS data set.

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Section: Resultsmentioning

confidence: 95%

Section: Application Of Diagnostic Statisticsmentioning

confidence: 99%

The TAOS Project: Statistical Analysis of Multi-Telescope Time Series Data

Lehner

Coehlo

Zhang

et al. 2010

PUBL ASTRON SOC PAC

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“…This is of course a limitation of aperture photometry in crowded fields, but it could be partly addressed by trialing a method to implement source-specific apertures that are adapted to every target in the field. 47 We also plot the predicted SNR as observed with an EMCCD at the same plate scale as the Kinetix in Fig. 6.…”

Section: Scmos Noise Modelmentioning

confidence: 99%

“…We also note that a number of the faintest detected sources have overestimated SNRs, which we believe is due to blending of the aperture fluxes with bright neighboring sources in this crowded field. This is of course a limitation of aperture photometry in crowded fields, but it could be partly addressed by trialing a method to implement source-specific apertures that are adapted to every target in the field 47 . We also plot the predicted SNR as observed with an EMCCD at the same plate scale as the Kinetix in Fig.…”

Section: Observations At Mcdonald Observatorymentioning

confidence: 99%

High-speed imaging system to detect stellar occultations by Kuiper belt and Oort cloud objects

Hitchcock,

Gomer

2024

J. Astron. Telesc. Instrum. Syst.

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The existence of kilometer size objects in the Oort cloud has been conjectured but not observed as these objects are too small and too far away to be detected by reflected sunlight with current telescopes. However, these objects could be detected by serendipitous occultations of stars. We outline a pilot study for a planned occultation survey that will mount high frame-rate sCMOS cameras in the otherwise unused areas in the focal planes of large, ground-based telescopes. Because gigabytes of imaging data are produced every second, making storage of the imaging impractical for long-term observing campaigns, the image processing must be done in real time. We describe a data system that processes up to 330 frames∕s of 3200 × 3200 images in real time and a procedure to analyze the recorded photometry for candidate occultation events by outer solar system objects. Although we did not detect any occultations, we describe successfully trialing our system taking continuous data on 7 nights of sCMOS observations of nearby open clusters with the 2.1 m telescope at McDonald Observatory, Texas.

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The TAIWAN-AMERICAN OCCULTATION SURVEY PROJECT STELLAR VARIABILITY. I. DETECTION OF LOW-AMPLITUDE Δ SCUTI STARS

Kim

Protopapas

Alcock

et al. 2010

The Astronomical Journal

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We analyzed data accumulated during 2005 and 2006 by the Taiwan-American Occultation Survey (TAOS) in order to detect short-period variable stars (periods of < ∼ 1 hour) such as δ Scuti. TAOS is designed for the detection of stellar occultation by small-size Kuiper Belt Objects (KBOs) and is operating four 50cm telescopes at an effective cadence of 5Hz. The four telescopes simultaneously monitor the same patch of the sky in order to reduce false positives. To detect short-period variables, we used the Fast Fourier Transform algorithm (FFT) inasmuch as the data points in TAOS light-curves are evenly spaced. Using FFT, we found 41 short-period variables with amplitudes smaller than a few hundredths of a magnitude and periods of about an hour, which suggest that they are low-amplitude δ Scuti stars (LADS). The light-curves of TAOS δ Scuti stars are accessible online at the Time Series Center website (http://timemachine.iic.harvard.edu). a Combination of TAOS field ID and TAOS star ID. b We doubled amplitudes derived by PERIOD04. c SNR of frequencies derived using PERIOD04. dThe number of identifications / the number of zipper runs. Note that we did not count zipper runs observed by only one telescope. e The B8 star found to be an A5 star as explained in the text.f The G5 star found to be an F0 star as explained in the text.

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The TAOS Project: High-Speed Crowded Field Aperture Photometry

Cited by 9 publications

References 5 publications

The TAOS Project: Statistical Analysis of Multi-Telescope Time Series Data

The TAOS Project: Statistical Analysis of Multi-Telescope Time Series Data

High-speed imaging system to detect stellar occultations by Kuiper belt and Oort cloud objects

The TAIWAN-AMERICAN OCCULTATION SURVEY PROJECT STELLAR VARIABILITY. I. DETECTION OF LOW-AMPLITUDE Δ SCUTI STARS

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