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We discuss the impact of special relativistic effects on the observed light curves and variability duty cycles of AGNs. We model the properties of AGN light curves at radio wavelengths using a simulated shot noise process in which the…

Astrophysics · Physics 2009-11-07 Matthew L. Lister

Simplified analytic methods are frequently used to model the light curves of supernovae and other energetic transients and to extract physical quantities, such as the ejecta mass and amount of radioactive heating. The applicability and…

High Energy Astrophysical Phenomena · Physics 2019-10-02 David K. Khatami , Daniel N. Kasen

In this study, we demonstrate some of the caveats in common statistical methods used for analysing astronomical variability timescales. We consider these issues specifically in the context of active galactic nuclei (AGNs) and use a more…

Astrophysics of Galaxies · Physics 2024-12-12 Sofia Kankkunen , Merja Tornikoski , Talvikki Hovatta

The study of X-ray time-lag spectra in active galactic nuclei (AGN) is currently an active research area, since it has the potential to illuminate the physics and geometry of the innermost region (i.e. close to the putative super-massive…

Instrumentation and Methods for Astrophysics · Physics 2016-06-29 A. Epitropakis , I. E. Papadakis

Many astrophysical phenomena are time-varying, in the sense that their brightness change over time. In the case of periodic stars, previous approaches assumed that changes in period, amplitude, and phase are well described by either…

Methodology · Statistics 2022-02-02 Giovanni Motta , Darlin Soto , Márcio Catelan

Rotational periods derived from autocorrelation (ACF) techniques on stars photometrically similar to the Sun in Kepler data have proven difficult to reliably determine. We investigate various instrumental and astrophysical factors affecting…

Solar and Stellar Astrophysics · Physics 2024-01-25 Canis Li , Gibor Basri

Modern-day time-domain photometric surveys collect a lot of observations of various astronomical objects and the coming era of large-scale surveys will provide even more information on their properties. Spectroscopic follow-ups are…

Instrumentation and Methods for Astrophysics · Physics 2023-09-19 Mariia Demianenko , Konstantin Malanchev , Ekaterina Samorodova , Mikhail Sysak , Aleksandr Shiriaev , Denis Derkach , Mikhail Hushchyn

(Abridged) Several phenomena in astrophysics generate light curves with time delays. Among these are reverberation mapping, and lensed quasars. In some systems, the measurement of the time-delay is complicated by the fact that the delayed…

Instrumentation and Methods for Astrophysics · Physics 2021-07-14 Ofer M. Springer , Eran O. Ofek

The gravitational field of a galaxy can act as a lens and deflect the light emitted by a more distant object such as a quasar. Strong gravitational lensing causes multiple images of the same quasar to appear in the sky. Since the light in…

Instrumentation and Methods for Astrophysics · Physics 2017-10-06 Hyungsuk Tak , Kaisey Mandel , David A. van Dyk , Vinay L. Kashyap , Xiao-Li Meng , Aneta Siemiginowska

The light curves of variable stars are commonly described using simple trigonometric models, that make use of the assumption that the model parameters are constant in time. This assumption, however, is often violated, and consequently, time…

Instrumentation and Methods for Astrophysics · Physics 2015-05-30 J. Pelt , N. Olspert , M. J. Mantere , I. Tuominen

We model the light-curves from radiation-driven clouds near an accreting black hole. Taking into account the multiple images due to strong gravitational lensing, we find that sharp spikes can significantly enhance the observed flux.…

High Energy Astrophysical Phenomena · Physics 2009-12-16 V. Karas

Physical studies of asteroids depend on an availability of lightcurve data. Targets that are easy to observe and analyse naturally have more data available, so their synodic periods are confirmed from multiple sources. Also, thanks to…

In the broad line region of AGN, acceleration occurs naturally when a cloud condenses out of the hot confining medium due to the increase in line opacity as the cloud cools. However, acceleration by radiation pressure is not very efficient…

Astrophysics of Galaxies · Physics 2016-07-13 Tim Waters , Daniel Proga

Temporal analysis of blazar flux is a powerful tool to draw inferences about the emission processes and physics of these sources. In the most general case, the available light curves are irregularly sampled and influenced by gaps, and in…

High Energy Astrophysical Phenomena · Physics 2020-06-10 Stefano Covino , Marco Landoni , Angela Sandrinelli , Aldo Treves

The ability to automatically and robustly self-verify periodicity present in time-series astronomical data is becoming more important as data sets rapidly increase in size. The age of large astronomical surveys has rendered manual…

Instrumentation and Methods for Astrophysics · Physics 2024-06-14 Niall Miller , Philip Lucas , Yi Sun , Zhen Guo , Calum Morris , William Cooper

Temporal analysis of radiation from Astrophysical sources like Active Galactic Nuclei, X-ray Binaries and Gamma-ray bursts provide information on the geometry and sizes of the emitting regions. Establishing that two light-curves in…

High Energy Astrophysical Phenomena · Physics 2017-04-14 Ranjeev Misra , Archana Bora , Gulab Dewangan

The field of visible-light continuous time series photometry is now at its golden age, manifested by the continuum of past (CoRoT, Kepler), present (K2), and future (TESS, PLATO) space-based surveys delivering high precision data with a…

Solar and Stellar Astrophysics · Physics 2017-06-14 Avi Shporer

The quasi-symmetric shape of the lightcurves, as seen in the X-rays and in the optical, together with the fast variations of the flux observed, suggest that the cooling time for the highest energy electrons may be shorter than the light…

Astrophysics · Physics 2007-05-23 Marco Chiaberge , Annalisa Celotti , Gabriele Ghisellini

We present a quantitative analysis of the effect of microlensing caused by random motion of individual stars in the galaxy which is lensing a background quasar. We calculate a large number of magnification patterns for positions of the…

Astrophysics · Physics 2016-08-30 Joachim Wambsganss , Tomislav Kundic

We systematically study pulsar light curves, taking into account the special relativistic effect, i.e., the Doppler factor due to the fast spin of the neutron stars, together with the time delay, which comes from the difference of the…

High Energy Astrophysical Phenomena · Physics 2018-12-05 Hajime Sotani , Umpei Miyamoto
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