相关论文: Absorption Measure Distribution in Mrk 509

We present the results of the analysis of the X-ray spectrum of the Seyfert 2 Mrk 348, observed by Suzaku and XMM-Newton. The overall spectrum of Mrk 348 can be described by a primary power law continuum seen through three layers of…

We present in this paper the results of a 270 ks Chandra HETGS observation in the context of a large multiwavelength campaign on the Seyfert galaxy Mrk 509. The HETGS spectrum allows us to study the high ionisation warm absorber and the…

We present 21-cm absorption measurements towards 12 radio continuum sources with previously identified thermally-unstable warm neutral medium (WNM). These observations were obtained with the Expanded Very Large Array (EVLA) and were…

Experimental apparatus and measurement technique are described for precision absorption measurements in sodium - noble gas mixtures. The absolute absorption coefficient is measured in the wavelength range from 425 nm to 760 nm with 2%…

By independently engineering strain and composition, this work demonstrates and investigates direct band gap emission in the mid-infrared range from GeSn layers grown on silicon. We extend the room-temperature emission wavelength above ~4.0…

We investigate the atomic hydrogen adsorption on Mg(0001) by using density-functional theory within the generalized gradient approximation and a supercell approach. The coverage dependence of the adsorption structures and energetics is…

We present a comparison between the 2001 XMM-Newton and 2005 Suzaku observations of the quasar, PG1211+143 at z=0.0809. Variability is observed in the 7 keV iron K-shell absorption line (at 7.6 keV in the quasar frame), which is…

By analyzing the X-ray spectrum of MCG-6-30-15 obtained with the HETG spectrometer on board the Chandra Observatory, we identify three kinematically distinct absorption systems; two outflow components intrinsic to MCG-6-30-15, and one local…

We show that a perfect absorber/thermal emitter exhibiting an absorption peak of 99.9% can be achieved in metallic nanostructures that can be easily fabricated. The very high absorption is maintained for large angles with a minimal shift in…

Fabrication, characterization, and analysis of an ultra-broadband lithography-free absorber is presented. An over 94% average absorption is experimentally achieved in the wavelength range of 450-1400 nm. This ultra-broadband absorption is…

We analyse the ROSAT PSPC hardness ratio and the 0.5-2 keV to 2-10 keV flux ratio of 65 Active Galactic Nuclei (AGN) for which there are both ROSAT archival observations available and 2-10 keV fluxes, mostly from the HEAO-1 MC-LASS survey.…

Frequency band of 30 to 300 GHz, which is termed as mm wave band offers 100 times bandwidth as compared to sub 6 GHz band. In this study, we propose a novel design which acts as a near unity absorber at 258 GHz or 0.258 THz in Y…

We have obtained spatially resolved spectra of the z=3.911 triply imaged QSO APM08279+5255 using the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope (HST). We study the line of sight equivalent width (EW)…

We report a detection of an absorption line at ~44.8 {\AA} in a > 500 ks Chandra HRC-S/LETG X-ray grating spectrum of the blazar H 2356-309. This line can be identified as intervening CV-K{\alpha} absorption, at z\approx0.112, produced by a…

Warm absorbers are found in many AGN and consist of clouds moving at moderate radial velocities, showing complex ionization structures and having moderate to large column densities. Using 1D numerical calculations, we confirm earlier…

The rate of photon absorption in warm dense matter (WDM) induced by free-free electron-ion collisions is derived from Sommerfeld's cross-section for non-relativistic bremsstrahlung emission, making use of detailed balance relations. Warm…

A new 3.2--3.5~$\mu$m spectrum of the protostar Mon~R2/IRS-3 confirms our previous tentative detection of a new absorption feature near 3.25 $\mu$m. The feature in our new spectrum has a central wavelength of 3.256 $\mu$m (3071 cm$^{-1}$)…

(Abridged) Many active galactic nuclei exhibit X-ray features typical of the highly ionized gas called "Warm Absorber" (WA). Such a material appears to be stratified, displaying zones of different density, temperature, and ionization. In…

We present a detailed study of the HI 21cm absorption system at z=0.0912 towards the radio quasar B0738+313. The uncommonly narrow main absorption line and weak secondary line are resolved for the first time. In addition we find it…

The X-ray spectra of some magnetized isolated neutron stars (NSs) show absorption features with equivalent widths (EWs) of 50 - 200 eV, whose nature is not yet well known. To explain the prominent absorption features in the soft X-ray…