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Related papers: Do the Kepler AGN Light Curves Need Re-processing?

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The power spectral density (PSD) represents a key property quantifying the stochastic or random noise type fluctuations in variable sources like Active Galactic Nuclei (AGN). In recent years, estimates of the PSD have been refined by…

High Energy Astrophysical Phenomena · Physics 2020-10-05 Nachiketa Chakraborty , Frank M. Rieger

We present results of our Power Spectral Density (PSD) analysis of 30 AGN using the 58 month light curves from Swift's Burst Alert Telescope (BAT) in the 14-150 keV band. PSDs were fit using a Monte Carlo based algorithm to take into…

High Energy Astrophysical Phenomena · Physics 2013-05-28 T. Taro Shimizu , Richard F. Mushotzky

We have carried out a systematic analysis of the nearby (z=0.0279) active galaxy Zw 229.015 using multi-epoch, multi-instrument and deep pointed observations with XMM-Newton, Suzaku, Swift and NuSTAR. Spectral and temporal variability are…

High Energy Astrophysical Phenomena · Physics 2019-07-31 S. Tripathi , S. G. H. Waddell , L. C. Gallo , W. F. Welsh , C-Y. Chiang

We have modified the graphical user interfaced close binary system analysis program CurveFit to the form WinKepler and applied it to 16 representative planetary candidate light curves found in the NASA Exoplanet Archive (NEA) at the Caltech…

Solar and Stellar Astrophysics · Physics 2015-06-18 M. D. Rhodes , E. Budding

We present the results from a monitoring campaign of the Narrow-Line Seyfert~1 galaxy PG 1211+143. The object was monitored with ground-based facilities (UBVRI photometry; from February to July, 2007) and with Swift (X-ray…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 R. Bachev , D. Grupe , S. Boeva , E. Ovcharov , A. Valcheva , E. Semkov , Ts. Georgiev , L. C. Gallo

The origin of the optical flux variability in active galactic nuclei (AGN) is largely unknown. Previous studies have correlated features of the variability structure function (SF) with AGN properties, though they mostly involved…

Astrophysics of Galaxies · Physics 2026-05-06 Ashley Hai Tung Tan , Christian Wolf , Neelesh Amrutha , Christopher A. Onken , John L. Tonry , Rachel Webster

We present the results of a detailed study of the X-ray power spectra density (PSD) functions of twelve X-ray bright AGN, using almost all the archival XMM-Newton data. The total net exposure of the EPIC-pn light curves is larger than 350…

High Energy Astrophysical Phenomena · Physics 2016-06-15 D. Emmanoulopoulos , I. E. Papadakis , A. Epitropakis , T. Pecháček , M. Dovčiak , I. M. McHardy

The results of recent AGN monitoring campaigns confirm the ``big picture'' of the echo paradigm, but the details of the emission-line light curves cannot be accurately reproduced with only the simplest assumptions, some of which must be…

Astrophysics · Physics 2007-05-23 Dan Maoz

AT2019pev is a nuclear transient in a narrow-line Seyfert 1 galaxy at $z=0.096$. The archival ultraviolet, optical and infrared data showed features of both tidal disruption events (TDEs) and active galactic nuclei (AGNs), and its nature is…

High Energy Astrophysical Phenomena · Physics 2022-08-03 Zhefu Yu , C. S. Kochanek , S. Mathur , K. Auchettl , D. Grupe , T. W. -S. Holoien

The Kepler field hosts the best studied sample of field star rotation periods. However, due to Kepler's large 4" pixels, many of its light curves are at high risk of contamination from background sources. The new Kepler Bonus Background…

Solar and Stellar Astrophysics · Physics 2025-06-05 Zachary R. Claytor , Jamie Tayar

Stellar light curves are well known to encode physical stellar properties. Precise, automated and computationally inexpensive methods to derive physical parameters from light curves are needed to cope with the large influx of these data…

Solar and Stellar Astrophysics · Physics 2021-03-17 Maryum Sayeed , Daniel Huber , Adam Wheeler , Melissa Ness

Many nearby AGNs display a significant short-term variability. In this work we re-analyze photometric data of four active galactic nuclei observed by Kepler in order to study the flickering activity, having as main goal that of searching…

Astrophysics of Galaxies · Physics 2017-07-26 A. Dobrotka , V. Antonuccio-Delogu , I. Bajcicakova

The reprocessing scenario is widely adopted in literature to explain the observed tight inter-band correlation and short lags in the UV/optical variations of active galactic nuclei (AGNs). In this work we look into the color variability of…

Astrophysics of Galaxies · Physics 2018-06-27 Fei-Fan Zhu , Jun-Xian Wang , Zhen-Yi Cai , Yu-Han Sun , Mou-Yuan Sun , Ji-XIan Zhang

The Kepler spacecraft has collected data of high photometric precision and cadence almost continuously since operations began on 2009 May 2. Primarily designed to detect planetary transits and asteroseismological signals from solar-like…

Instrumentation and Methods for Astrophysics · Physics 2015-06-05 K. Kinemuchi , T. Barclay , M. Fanelli , J. Pepper , M. Still , Steve B. Howell

Lags measured from correlated X-ray/UV/optical monitoring of AGN allow us to determine whether UV/optical variability is driven by reprocessing of X-rays or X-ray variability is driven by UV/optical seed photon variations. We present the…

High Energy Astrophysical Phenomena · Physics 2015-06-22 I. M. McHardy , D. T. Cameron , T. Dwelly , S. Connolly , P. Lira , D. Emmanoulopoulos , J. Gelbord , E. Breedt , P. Arevalo , P. Uttley

A damped random walk (DRW) process is often used to describe the temporal UV/optical continuum variability of active galactic nuclei (AGN). However, recent investigations have shown that this model fails to capture the full spectrum of AGN…

Astrophysics of Galaxies · Physics 2025-10-21 Weixiang Yu , Gordon T. Richards , John J. Ruan , Michael S. Vogeley , Franz E. Bauer , Matthew J. Graham

For the past three decades, and until recently, there has been a serious discrepancy between the observed and theoretical values of the apsidal motion rate dw/dt of the eccentric eclipsing binary DI Her, which has even been interpreted…

Solar and Stellar Astrophysics · Physics 2015-05-18 A. Claret , G. Torres , M. Wolf

We report the discovery of a new relationship between a simple morphological characteristic of light curves produced by starspots and stellar rotation periods. The characteristic we examine is whether the light curve exhibits one dip or two…

Solar and Stellar Astrophysics · Physics 2018-08-29 Gibor Basri , Hieu T. Nguyen

Inconsistent conclusions are obtained from recent active galactic nuclei (AGNs) accretion disk inter-band time-lag measurements. While some works show that the measured time lags are significantly larger (by a factor of $\sim 3$) than the…