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Related papers: A new algorithm for detecting X-ray shots in Cyg X…

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NICER has a comparatively low background rate, but it is highly variable, and its spectrum must be predicted using measurements unaffected by the science target. We describe an empirical, three-parameter model based on observations of seven…

We show that the rms-flux relation recently discovered in the X-ray light curves of Active Galactic Nuclei (AGN) and X-ray binaries (XRBs) implies that the light curves have a formally non-linear, exponential form, provided the rms-flux…

Astrophysics · Physics 2009-11-10 P. Uttley , I. M. McHardy , S. Vaughan

High-energy X-ray diffraction methods can non-destructively map the 3D microstructure and associated attributes of metallic polycrystalline engineering materials in their bulk form. These methods are often combined with external stimuli…

Temporal and spectral properties of X-ray rapid variability of Cyg X-1 are studied by an approach of correlation analysis in the time domain on different time scales. The correlation coefficients between the total intensity in 2-60 keV and…

Astrophysics · Physics 2009-10-31 T. P. Li , Y. X. Feng , L. Chen

We present a new method for determining the sensitivity of X-ray imaging observations, which correctly accounts for the observational biases that affect the probability of detecting a source of a given X-ray flux, without the need to…

Astrophysics · Physics 2009-11-13 A. Georgakakis , K. Nandra , E. S. Laird , J. Aird , M. Trichas

Standard shot-noise models, which seek to explain the broadband noise variability that characterises the X-ray lightcurves of X-ray binaries and active galaxies, predict that the power spectrum of the X-ray lightcurve is stationary (i.e.…

Astrophysics · Physics 2009-11-06 Philip Uttley , Ian M. McHardy

Gain calibration of x-ray area detectors is a challenge due to the inability to generate an x-ray flat field at the selected photon energy that the beamline operates at, which has a strong influence on the detector's gain behavior. A method…

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…

High Energy Astrophysical Phenomena · Physics 2016-02-17 Dheeraj R. Pasham , Tod E. Strohmayer , S. Bradley Cenko , Margaret L. Trippe , Richard F. Mushotzky , Poshak Gandhi

Rapid spectral changes in the hard X-ray on a time scale down to ~0.1 s are studied by applying "shot analysis" technique to the Suzaku observations of the black hole binary Cygnus X-1, performed on 2008 April 18 during the low/hard state.…

High Energy Astrophysical Phenomena · Physics 2015-06-15 S. Yamada , H. Negoro , S. Torii , H. Noda , S. Mineshige , K. Makishima

We have developed an algorithm that, starting from the observed properties of the X-ray spectrum and fast variability of an X-ray binary allows the production of synthetic data reproducing observables such as power density spectra and time…

High Energy Astrophysical Phenomena · Physics 2015-05-19 Y. X. Wu , T. M. Belloni , L. Stella

We analyze the ${\it Kepler}$ monitoring light curve of a blazar W2R 1926$+$42 to examine features of microvariability by means of the "shot analysis" technique. We select 195 intra-day, flare-like variations (shots) for the continuous…

High Energy Astrophysical Phenomena · Physics 2017-02-01 Mahito Sasada , Shin Mineshige , Shinya Yamada , Hitoshi Negoro

I discuss some practical aspects of the analysis of millisecond time variability X-ray data obtained from accreting neutron stars and black holes. First I give an account of the statistical methods that are at present commonly applied in…

Astrophysics · Physics 2007-05-23 M. van der Klis

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…

The light curves from a variety of celestial objects display aperiodic variations, often giving rise to red-noise components in their power spectra. Searching for a narrow power spectrum peak resulting from a periodic modulation over the…

Astrophysics · Physics 2009-10-28 G. L. Israel , L. Stella

From 2005 to 2009, 25 observations of Cyg X-1 were performed with Suzaku, achieving a total exposure of 446 ks. In all observations, the source was found in the low/hard state, while the 1.5--12.0 keV count rate of the All-Sky Monitor…

Aims. We investigate observations of the X-ray binary Cygnus X-1 with unusually high hardness and low flux. In particular, we study the characteristic frequencies seen in the PDS and the hardness-flux correlation within and between these…

Astrophysics · Physics 2009-02-25 M. Axelsson , L. Hjalmarsdotter , L. Borgonovo , S. Larsson

Rapid optical transient events can be hard to detect because of the limited number of photons they produce. I discuss a method of inferring the presence of fast, chaotic variability in photometry using the normalized autocorrelation…

Instrumentation and Methods for Astrophysics · Physics 2025-07-03 Brian C. Lacki

Thanks to recurrent observations of the black hole binary Cyg X-1 carried out over 15 years the INTEGRAL satellite has collected the largest data set in the hard X-ray band for this source. We have analyzed these data, complemented by data…

High Energy Astrophysical Phenomena · Physics 2020-06-24 Piotr Lubiński , Alexandros Filothodoros , Andrzej A. Zdziarski , Guy Pooley

We analyzed RXTE/PCA observations of Cyg X-1 from 1996-1998. We found a tight correlation between the characteristic noise frequencies (e.g. the break frequency nu_br) and the spectral parameters in the low spectral state. The amplitude of…

Astrophysics · Physics 2007-05-23 M. Gilfanov , E. Churazov , M. Revnivtsev

We investigate the shot cutoff timescale evolutions during different spectral states in the black hole binary Cygnus X-1 with the recently proposed w spectral analysis technique. For low energy shots, their cutoff timescale decreases from…

Astrophysics · Physics 2011-05-10 Hua Feng , Shuang-Nan Zhang , Ti-Pei Li