Related papers: Photon Interval Statistics Measure Rapid Variabili…

Quantities characterizing temporal property, e.g. power density, coherence, and time lag, can be defined and calculated directly in the time domain without using the Fourier transformation. Spectral hardness, variability duration, and…

We report the measurement of the photons flux produced in parametric down-conversion, performed in photon counting regime with actively quenched silicon avalanche photodiodes as single photon detectors. Measurements are done with the…

The largest group of sources identified by EGRET are Blazars. This sub-class of AGN is well known to vary in flux in all energy bands on time-scales ranging from a few minutes (in the optical and X-ray bands) up to decades (radio and…

We used a ~300 ks long XMM-Newton observation of the Seyfert 1 galaxy MCG-6-30-15 to study the correlation between the 0.2-10 keV X-ray and the 3000-4000 A bands. We found a significant correlation peak at a time lag of 160 ks where the UV…

We examine a method to detect the light speed variation from gamma ray burst data observed by the Fermi Gamma-ray Space Telescope (FGST). We suggest new criteria to determine the characteristic time for low energy photons by the energy…

Previously, the X-ray emission of zeta Puppis was found to be variable with light curves harbouring "trends" with a typical timescale longer than the exposure length. The origin of these changes was proposed to be linked to large-scale…

X-ray polarimetry of accreting compact objects has revealed fast time variations in the polarization angle (PA), suggesting that the geometry and/or optical depth of the Comptonization region is changing rapidly. This prompts investigations…

Previous results from the authors concerning the arising a tiny photon anomalous paramagnetic moment are also interpreted as a red-shift in analogy to the gravitational known effect. It is due to the photon interaction with the magnetized…

When it comes to identifying or to characterizing gamma-ray sources, X-ray observations are of paramount importance. Correlated X-and-gamma-ray flux variations are a powerful identification tool, if the gamma-ray source is unidentified, or…

This paper presents the results of a study of X-ray spectral and flux variability on time scales from months to years, of the 123 brightest objects (including 46 type-1 AGN and 28 type-2 AGN) detected with XMM-Newton in the Lockman Hole…

We present timing analysis for a Rossi X-ray Timing Explorer observation of Cygnus X-1 in its hard/low state. This was the first RXTE observation of Cyg X-1 taken after it transited back to this state from its soft/high state. RXTE's large…

In order to study transient phenomena in the Universe, existing and forthcoming imaging surveys are covering wide areas of sky repeatedly over time, with a range of cadences, point spread functions, and depths. We describe here a framework…

We present a new method for optimally extracting point-source time variability information from a series of images. Differential photometry is generally best accomplished by subtracting two images separated in time, since this removes all…

X-ray free electron laser (XFEL) experiments have brought unique capabilities and opened new directions in research, such as creating new states of matter or directly measuring atomic motion. One such area is the ability to use finely…

Active galactic nuclei are known to exhibit flux variations across the entire electromagnetic spectrum. Among these, correlations between UV/optical and X-ray flux variations serve as a key diagnostics for understanding the physical…

The fact that the standard dispersion relation for photons in vacuum could be modified because of their interaction with the quantum nature of spacetime has been proposed more than two decades ago. A quantitative model [Jacob \& Piran, JCAP…

We use a wavelet technique to investigate the time variations in the light curves from a sample of GRBs detected by Fermi and Swift. We focus primarily on the behavior of the flaring region of Swift-XRT light curves in order to explore…

An experiment is proposed in which the overall path taken by a photon is indicated by the timing of a twin herald photon, while a particular segment of that path is determined by interference. The experiment is to be carried out in two…

We analyze simultaneous radio-X-ray data of Cygnus X-1 from the Ryle telescope (RT) and RXTE over more than 4 a. We show that apparent correlations on short time scales in the lightcurves of Cyg X-1 are probably the coincidental outcome of…

X-ray free electron laser (XFEL) can provide X-ray light with about four order of magnitude higher flux than synchrotron radiation. Pulse light from XFEL interacts with the target and the resulting photons are collected by detectors. The…