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Energetics considerations imply that the broad-line region (BLR) has a high covering factor. The absence of absorption from the BLR means that the BLR has to have a flattened distribution and be seen through a polar hole. The BLR is the…

Astrophysics · Physics 2008-07-21 C. Martin Gaskell , Rene W. Goosmann , Elizabeth S. Klimek

Reverberation mapping is a proven technique that is used to measure the size of the broad emission-line region and central black hole mass in active galactic nuclei. More ambitious reverberation mapping programs that are well within the…

Astrophysics · Physics 2009-11-10 B. M. Peterson , K. Horne

The relation between the jump length probability distribution function and the spectral line profile in resonance atomic radiation trapping is considered for Partial Frequency Redistribution (PFR) between absorbed and reemitted radiation.…

We derive a theoretical relation between $R_{BLR}$, the size of the broad-emission-line region of active galactic nuclei, and the observed soft X-ray luminosity and spectrum. We show that in addition to the well known $R_{BLR}\sim L^{1/2}$…

Astrophysics · Physics 2007-05-23 Amri Wandel

Transfer learning has recently shown significant performance across various tasks involving deep neural networks. In these transfer learning scenarios, the prior distribution for downstream data becomes crucial in Bayesian model averaging…

Machine Learning · Computer Science 2024-03-13 Hyungi Lee , Giung Nam , Edwin Fong , Juho Lee

Variability studies of the broad emission lines of Active Galactic Nuclei (AGNs) and quasars show stochastic radial velocity variations (i.e., fluctuations in the centroid of the line), 'jitter', on timescales of weeks to months. This…

Astrophysics of Galaxies · Physics 2026-02-23 Mary Ogborn , Michael Eracleous , Jessie C. Runnoe , Massimo Dotti , Niana N. Mohammed , Collin M. Dabbieri

This paper studies nonparametric regression with repeated measurements when the response in the target domain is unobservable or costly to collect. We adopt a transfer learning framework that leverages a source domain with observable…

Methodology · Statistics 2026-05-26 Yingxuan Wang , Xiangyu Xing , Wangli Xu

The Lyman-alpha (LyA) line of atomic hydrogen encodes crucial information about both the intrinsic sources and surrounding environments of star-forming regions throughout the Universe. Due to the complexity of resonant scattering, analytic…

Astrophysics of Galaxies · Physics 2025-07-22 Aaron Smith , Kevin Lorinc , Olof Nebrin , Bing-Xin Lao

Reverberation mapping uses time-delayed variations in photoionised emission lines to map the geometry and kinematics of emission-line gas in active galactic nuclei. In previous work, the light travel time delay tau=R(1+cos(theta))/c and…

Astrophysics · Physics 2009-11-07 Keith Horne , Kirk T Korista , Michael R Goad

The improvement of the calibration relation for determining the size of the broad-line region from the observed optical luminosity of active galactic nuclei (AGN) is a necessary task to study fundamental parameters of distant AGNs such as…

This paper presents a distributed estimator for a deterministic parametric physical field sensed by a homogeneous sensor network and develops a new transformed expression for the Cramer-Rao lower bound (CRLB) on the variance of distributed…

Information Theory · Computer Science 2015-06-17 Salvatore Talarico , Natalia A. Schmid , Marwan Alkhweldi , Matthew C. Valenti

The Transfer Matrix Method (TMM) is a widely used technique for modeling linear propagation of electromagnetic waves through stratified layered media. However, since its extension to inhomogeneous and nonlinear systems is not…

Optics · Physics 2025-06-23 Karol Sajnok , Michał Matuszewski

We investigate transient radiation processes in the non-linear superradiance (SR) regime of the Doppler broadened Maxwell-Bloch equations when the velocity distribution is of total bandwidth greatly exceeding that of the transient process…

The broad line region (BLR) of luminous active galactic nuclei (AGN) is a prominent observational signature of the accretion flow around supermassive black holes, which can be used to measure their masses (M_BH) over cosmic history. Due to…

Astrophysics of Galaxies · Physics 2015-06-24 Jonathan Stern , Joseph F. Hennawi , Jörg-Uwe Pott

This work is motivated by the problem of predicting downward solar radiation flux spherical maps from the observation of atmospheric pressure at high cloud bottom. To this aim nonlinear functional regression is implemented under…

Methodology · Statistics 2025-02-17 Diana P. Ovalle-Muñoz , M. Dolores Ruiz-Medina

Quasars have been proposed as a new class of standard candles analogous to Supernovae, as their large redshift range and high luminosities make them excellent candidates. Reverberation mapping (RM) method enables to estimate the distance to…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-09 Mary Loli Martínez-Aldama , Bożena Czerny , Damian Kawka , Vladimir Karas , Swayamtrupta Panda , Michal Zajaček , Piotr T. Życki

In nonparametric regression analysis, errors are possibly correlated in practice, and neglecting error correlation can undermine most bandwidth selection methods. When no prior knowledge or parametric form of the correlation structure is…

Methodology · Statistics 2025-04-29 Sisheng Liu , Xiaoli Kong

This paper develops the first method for the exact simulation of reflected Brownian motion (RBM) with non-stationary drift and infinitesimal variance. The running time of generating exact samples of non-stationary RBM at any time $t$ is…

Probability · Mathematics 2013-12-30 Mohammad Mousavi , Peter W. Glynn

Resolving the accretion disks and broad line regions (BLRs) of active galactic nuclei (AGNs) can probe the physics behind supermassive black holes (SMBHs) fueling and weigh SMBHs. With time-domain observations, the reverberation mapping…

The relationship between observed tracers such as galaxies and the underlying dark matter distribution is crucial in extracting cosmological information. As the linear bias model breaks down at quasi-linear scales, the standard perturbative…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Xin Wang , Alex Szalay