Related papers: New spectral classification technique for X-ray so…
We present a quasar candidate identification technique based on multicolor photometry. The traditional multi-dimensional method (2 $\times$ N dimensions, where N is the number of the color-color diagrams) is reduced to a one-dimensional…
A quantum illumination protocol exploits correlated light beams to enhance the probability of detection of a partially reflecting object lying in a very noisy background. Recently a simple photon-number-detection based implementation of a…
We analyze 18 sources that were found to show interesting properties of periodicity, very soft spectra and/or large long-term variability in X-rays in our project of classification of sources from the 2XMMi-DR3 catalog but were poorly…
We present first results of the X-ray spectral analysis of the 500 ksec deep survey obtained with XMM-Newton on the Chandra Deep Field South (CDFS). Statistical distributions of spectral index and intrinsic absorption are derived for a…
We introduce a procedure to identify very soft X-ray sources (VSSs) in external galaxies. Our immediate goal was to formulate a systematic procedure to identify luminous supersoft X-ray sources (SSSs), so as to allow comparisons among…
[ABRIGED] We present the optical identification of a sample of 695 X-ray sources detected in the first 1.3 deg^2 of the XMM-COSMOS survey, down to a 0.5-2 keV (2-10 keV) limiting flux of ~10^-15 erg cm-2 s-1 (~5x10^-15 erg cm^-2 s-1). We…
We examine the X-ray spectra and variability of the sample of X-ray sources with L_X = 10^{31}-10^{33} erg s^{-1} identified within the inner 9' of the Galaxy. Very few of the sources exhibit intra-day or inter-month variations. We find…
We describe the method used to detect sources for the Herschel-ATLAS survey. The method is to filter the individual bands using a matched filter, based on the point-spread function (PSF) and confusion noise, and then form the inverse…
We present results from a study of 2-8 keV X-ray sources detected by the Advanced CCD Imaging Spectrometer (ACIS) instrument on the Chandra X-ray Observatory in the field of the z=0.516 cluster CRSS J0030.5+2618. In our 63.5 arcmin^2 search…
We present a powerful new algorithm that combines both spatial information (event locations and the point spread function) and spectral information (photon energies) to separate photons from overlapping sources. We use Bayesian statistical…
Context. Serendipitous X-ray surveys have proven to be an efficient way to find rare objects, for example tidal disruption events, changing-look active galactic nuclei (AGN), binary quasars, ultraluminous X-ray sources (ULXs), and…
The hyperspectral X-ray imaging has been long sought in various fields from material analysis to medical diagnosis. Here we propose a new semiconductor detector structure to realize energy-resolved imaging at potentially low cost. The…
We demonstrate two new approaches that have been developed to aid the production of future hard X-ray catalogs, and specifically to reduce the reliance on human intervention during the detection of faint excesses in maps that also contain…
Spectroscopy has an illustrious history delivering serendipitous discoveries and providing a stringent testbed for new physical predictions, including applications from trace materials detection, to understanding the atmospheres of stars…
Imaging point sources with low angular separation near or below the Rayleigh criterion is important in astronomy, e.g., in the search for habitable exoplanets near stars. However, the measurement time required to resolve stars in the…
Chandra observations of nearby galaxies have revealed a number of X-ray sources characterized by high luminosities ($L_X > \sim10^{36}$ erg s$^{-1}$) and $k T$ in the range $100 - 350$ eV. These ``quasisoft X-ray sources'' (QSSs) are harder…
X-ray calorimeters routinely achieve very high spectral resolution, typically a few eV full width at half maximum (FWHM). Measurements of calorimeter line shapes are usually dominated by the natural linewidth of most laboratory calibration…
With excellent angular resolution, good energy resolution and broad energy band, the Chandra ACIS is the best instrument for studying the X-ray halos around some galactic X-ray point sources caused by the dust scattering of X-rays in the…
X-rays astrophysical sources have been almost exclusively characterized through imaging, spectroscopy and timing analysis. Nevertheless, more observational parameters are needed because some radiation mechanisms present in neutrons stars or…
We have investigated the X-ray spectral properties of a sample of 138 X-ray sources detected serendipitously in $XMM-Newton$ observations of the Galactic plane, at an intermediate to faint flux level. We divide our sample into 5 subgroups…