Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 7 of 7 for “"Periodic variability"”.
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Mathematical and Deep Learning Methods in High-Energy Physics: From Temporal Variability in M82 ULXs to Spatial Features in Planck Maps
… starburst galaxies, aiming to characterize quasi-periodic variability that reflects the physics of accretion onto compact objects. On the other hand, we develop a machine-learning method to detect and classify sources in wide-field infrared survey maps, where instrumental noise and foregrounds …
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Variability of black-hole accretion discs: a theoretical study
… Observations reveal that these systems exhibit variability on a range of time scales. This thesis investigates phenomena occurring in black-hole accretion discs which are likely to induce high-frequency quasi-periodic variability. Two classes of pseudo-relativistic theoretical models are …
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Data-driven Approaches to Stellar Variability Detection and Characterisation
… light curves from NGTS, finding 16, 880 periodic variability signals from 829, 481 light curves. I combated the noise and aliasing associated with ground-based photometry to produce a stellar variability sample that rivals those from previous space-based photometric studies. I assessed …
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Conceptualising and quantifying the nonlinear, chaotic climate: implications for climate model experimental design
… IC influence appear to be attributable to aperiodic and quasi-periodic variability in the model. It is found that, over some spatial domains, significant (p < 0.01) differences in atmospheric variable "climatologies", taken from 60-year distributions of model trajectories, occur due to IC …
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SALT and TESS monitoring of central stars of planetary nebulae
… periodograms were used to search for periodic variability in the RV and photometry time-series data. The results were discussed based on short (0 – 10 days), intermediate (10 – 103 days) and long (103 – 104 days) orbital period ranges. Compatible scenarios for each range were estimated …
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Very High Energy Gamma-Rays from Binary Systems
… applying tests for secular, excess and periodic variability. Strong evidence is found for modulation of the observed gamma-ray flux on the orbital period of ~3.9 days. Following a brief discussion of the procedures required for spectral analysis of VHE gamma-ray data, results are …