The interstellar oxygen-K absorption edge as 
 observed  by XMM-Newton

Vries, C. P. de; Herder, J. W. den; Kaastra, J. S.; Paerels, F.; Boggende, A. J. den; Rasmussen, Andrew

doi:10.1051/0004-6361:20030551

Cited by 43 publications

(55 citation statements)

References 17 publications

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“…-Non-routine calibrations: in addition, non-routine calibrations are carried out to investigate certain aspects. A detailed measurement of the Crab spectrum was carried out with the aim of calibrating the absolute effective area (Kaastra et al 2009) and of Sco X-1 with the aim to fully characterize the X-ray absorption edge structures present in the CCDs response (de Vries et al 2003).…”

Section: Calibration Methodsmentioning

confidence: 99%

Calibration and in-orbit performance of the reflection grating spectrometer onboardXMM-Newton

Vries

Herder

Gabriel

et al. 2015

A&A

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Context. XMM-Newton was launched on 10 December 1999 and has been operational since early 2000. One of the instruments onboard XMM-Newton is the reflection grating spectrometer (RGS). Two identical RGS instruments are available, with each RGS combining a reflection grating assembly and a camera with charge-coupled devices to record the spectra. Aims. We describe the calibration and in-orbit performance of the RGS instrument. By combining the preflight calibration with appropriate inflight calibration data including the changes in detector performance over time, we aim at profound knowledge about the accuracy in the calibration. This will be crucial for any correct scientific interpretation of spectral features for a wide variety of objects. Methods. Ground calibrations alone are not able to fully characterize the instrument. Dedicated inflight measurements and constant monitoring are essential for a full understanding of the instrument and the variations of the instrument response over time. Physical models of the instrument are tuned to agree with calibration measurements and are the basis from which the actual instrument response can be interpolated over the full parameter space. Results. Uncertainties in the instrument response have been reduced to <10% for the effective area and <6 mÅ for the wavelength scale (in the range from 8 Å to 34 Å). The remaining systematic uncertainty in the detection of weak absorption features has been estimated to be 1.5%. Conclusions. Based on a large set of inflight calibration data and comparison with other instruments onboard XMM-Newton, the calibration accuracy of the RGS instrument has been improved considerably over the preflight calibrations.

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Section: Calibration Methodsmentioning

confidence: 99%

Calibration and in-orbit performance of the reflection grating spectrometer onboardXMM-Newton

Vries

Herder

Gabriel

et al. 2015

A&A

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“…Finally, at 0.530 ± 0.003 keV some absorption line-like residuals, in addition to the known instrumental absorption line (de Vries et al 2003), still remain. Including at this position a second absorption line in the fit yields an energy that is interpreted as the 1s − 2p transition of compound oxygen (Fig.…”

Section: Cyg X-2 Rgs Spectral Analysismentioning

confidence: 97%

Absorption and scattering by interstellar dust: an XMM-Newton observation of Cyg X-2

Costantini

Freyberg

Predehl

2005

A&A

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We present results of the XMM-Newton observation of the bright X-ray binary Cyg X-2. In our analysis we focus on the absorption and scattering of the X-ray emission by interstellar dust distributed along the line of sight. The scattering halo around Cyg X-2, observed with the CCD detector EPIC-pn, is well detected up to ∼7 arcmin and contributes ∼5-7% to the total source emission at 1 keV, depending on the dust size distribution model considered. For the first time spatially resolved spectroscopy of a scattering halo is performed. In the halo spectrum we clearly detect the signature of the interstellar dust elements: O, Mg, and Si. In the 0.4−2 keV band, the spectral modeling of the halo shows a major contribution of silicates (olivine and pyroxene). The spatial analysis of the halo surface brightness profile shows that the dust is smoothly distributed toward Cyg X-2 at least for ∼60% of the path to the source. However, given the substantial pile-up, we could not investigate fainter or narrower components of the halo. Within this observation limit, the data do not show preference for a specific dust size distribution. In this analysis we used the Mie theory to compute the differential scattering cross section. The RGS data were used to investigate the ISM absorption. The absorption spectrum shows complexity around the oxygen edge at ∼0.54 keV, which cannot be explained in a unique way: it involves either absorption by molecular oxygen or ionized atomic oxygen, as proposed in other studies of Cyg X-2. Combining the RGS results with the additional information on dust grains provided by the EPIC-pn spectrum of the scattered radiation we estimate a column density for dust absorption by oxygen, provided that it is locked in silicate grains.

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“…We had excluded these wavelengths (λ ∼ 23.35 Å) from our previous analysis due to the coincidence of the wavelengths of O ii 1s-2p with an instrumental feature in RGS1 and LETG. de Vries et al (2003) argued that in both instruments there is O i 1s-2p (λ = 23.5 Å) absorption, shifted to 23.35 Å due to O i in the solid compounds of the instruments (metal oxide or water ice). This feature is included in the effective area calculations of both RGS and LETG.…”

Section: Oii 1s-2pmentioning

confidence: 99%

Discovery of Galactic O iv and O v X-ray absorption due to transition temperature gas in the PKS 2155-304 spectrum

Nevalainen

Wakker

Kaastra

et al. 2017

A&A

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FUV observations have revealed the transition temperature gas (TTG; log T (K) ∼5), located in the lower Galactic halo and in the High Velocity Clouds. However, the corresponding X-ray absorption has so far remained mostly undetected. In order to make an improvement in this respect in Galactic X-ray absorption studies, we accumulated very deep (∼ 3 Ms) spectra of the blazar PKS 2155-304 obtained with the spectrometers RGS1, RGS2, LETG/HRC and LETG/ACIS-S and studied the absorption lines due to the intervening Galactic components. The very high quality of the data and the coverage of important wavelengths with at least two independent instruments allowed us to reliably detect ten Galactic lines with better than 99.95% confidence. We discovered significant absorption from blended O iv transitions 1s-2p 2 S (22.571 Å), 1s-2p 2 P (22.741 Å) and 1s-2p 2 D (22.777 Å), and from the O v transition 1s-2p (22.370 Å) from TTG at log T (K) = 5.2 ± 0.1. A joint X-ray and FUV analysis indicated that photoionisation is negligible for this component and that the gas is in a cooling transition phase. However, the temperature is high enough that the column density ratio N(O iv)/N(O v) is not significantly different from that in collisional ionisation equilibrium (CIE). Under CIE we obtained N OIV = 3.6±2.0 × 10 15 cm −2 , corresponding to N H = 1.0±0.5 × 10 19 Z Z TTG cm −2 .

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The interstellar oxygen-K absorption edge as observed by XMM-Newton

Cited by 43 publications

References 17 publications

Calibration and in-orbit performance of the reflection grating spectrometer onboardXMM-Newton

Calibration and in-orbit performance of the reflection grating spectrometer onboardXMM-Newton

Absorption and scattering by interstellar dust: an XMM-Newton observation of Cyg X-2

Discovery of Galactic O iv and O v X-ray absorption due to transition temperature gas in the PKS 2155-304 spectrum

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