相关论文: OzDES Reverberation Mapping Program: Lag recovery …

We broadly explore the effects of systematic errors on reverberation mapping lag uncertainty estimates from {\tt JAVELIN} and the interpolated cross-correlation function (ICCF) method. We focus on simulated lightcurves from random…

Signal recovery from nonlinear measurements involves solving an iterative optimization problem. In this paper, we present a framework to optimize the sensing parameters to improve the quality of the signal recovered by the given iterative…

We present the first results of a 4.5 year monitoring campaign of the three bright images of multiply imaged $z=2.805$ quasar SDSS J2222+2745 using the Gemini North Multi-Object Spectrograph (GMOS-N) and the Nordic Optical Telescope (NOT).…

We report the first results of a systematic investigation to characterize blazar variability power spectral densities (PSDs) at optical frequencies using densely sampled (5--15 minutes integration time), high photometric accuracy…

We present the results of an intensive six-month optical continuum reverberation mapping campaign of the Seyfert 1 galaxy PG 2130+099 at redshift z=0.063. The ground-based photometric monitoring was conducted on a daily basis with the…

By means of C-OTDR (Correlation - Optical Time Domain Reflectometry), we measured the latency of100 km fiber with an accuracy of a few picoseconds. Based on iterating 49 measurements, we calculated a standard deviation of 12 ps between the…

We present a series of simulations to demonstrate that high-fidelity velocity-delay maps of the emission-line regions in active galactic nuclei can be obtained from time-resolved spectrophotometric data sets like those that will arise from…

Reverberation mapping (RM) of active galactic nuclei (AGNs) has been used over the past three decades to determine AGN broad-line region (BLR) sizes and central black-hole masses, and their relations with the AGN's luminosity. Until…

Using simultaneous optical (VLT/FORS2) and X-ray (XMM-Newton) data of NGC 5408, we present the first ever attempt to search for a reverberation signal in an ultraluminous X-ray source (NGC 5408 X-1). The idea is similar to AGN broad line…

We present a new release of the RELTRANS model to fit the complex cross-spectrum of accreting black holes as a function of energy. The model accounts for continuum lags and reverberation lags self-consistently in order to consider the…

We search for OVI absorption in a Keck HIRES spectrum of the z=3.62 quasar Q1422+231. Comparison of CIV measurements to cosmological simulations shows that \lya forest absorbers with N_HI > 10^{14.5} have [C/H]~=-2.5, for the UV background…

We study metal line absorption of CIV, CII, SiIV, and NV at redshifts z=3.5 to z=2 within the framework of a cosmological model for the Lyman alpha forest, comparing the results of numerical simulations to recent observations by Songaila &…

We assemble the largest CIV absorption line catalogue to date, leveraging machine learning, specifically Gaussian processes, to remove the need for visual inspection for detecting CIV absorbers. The catalogue contains probabilities…

Orthogonal least square (OLS) is an important sparse signal recovery algorithm for compressive sensing, which enjoys superior probability of success over other well-known recovery algorithms under conditions of correlated measurement…

The absorption by gas toward background continuum sources informs us about the cosmic density of gas components as well as the hosts responsible for the absorption (galaxies, clusters, cosmic filaments). Cosmic absorption line distributions…

We consider the problem of exact recovery of a $k$-sparse binary vector from generalized linear measurements (such as logistic regression). We analyze the linear estimation algorithm (Plan, Vershynin, Yudovina, 2017), and also show…

This paper presents light curves and the first systematic characterization of variability of the 106 objects in the Fermi Large Area Telescope (LAT) Bright AGN Sample (LBAS). Weekly light curves obtained during the first 11 months of survey…

The size of the dust torus in Active Galactic Nuclei (AGN) and their high-luminosity counterparts, quasars, can be inferred from the time delay between UV/optical accretion disk continuum variability and the response in the mid-infrared…

We consider the Orthogonal Least-Squares (OLS) algorithm for the recovery of a $m$-dimensional $k$-sparse signal from a low number of noisy linear measurements. The Exact Recovery Condition (ERC) in bounded noisy scenario is established for…

We address the problem of estimating time and frequency shifts of a known waveform in the presence of multiple measurement vectors (MMVs). This problem naturally arises in radar imaging and wireless communications. Specifically, a signal…