K-Shell Photoabsorption of Magnesium Ions

Hasoğlu, M. F.; Abdel‐Naby, Sh. A.; Gatuzz, E.; García, Javier A.; Kallman, T. R.; Mendoza, C.; Gorczyca, T. W.

doi:10.1088/0067-0049/214/1/8

Cited by 16 publications

(19 citation statements)

References 50 publications

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“…We update the photo-absorption cross section of neutral magnesium in Spex, adding the resonance transitions, 1s → np, calculated using the Flexible Atomic Code 7 (A. Raassen, private communication). Our neutral Mg K-shell cross section is consistent with the Mg i profile obtained by Hasoglu et al (2014) applying the R−matrix method.…”

Section: Continuumsupporting

confidence: 82%

Interstellar dust along the line of sight of GX 3+1

Rogantini

Costantini

Zeegers

et al. 2019

A&A

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Context. Studying absorption and scattering of X-ray radiation by interstellar dust grains allows us to access the physical and chemical properties of cosmic grains even in the densest regions of the Galaxy. Aims. We aim at characterising the dust silicate population which presents clear absorption features in the energy band covered by the Chandra X-ray Observatory. Through these absorption features, in principle, it is possible to infer the size distribution, composition, and structure of silicate in the interstellar medium. In particular, in this work we investigate the magnesium and silicon K-edges. Methods. By using newly acquired synchrotron measurements, we build X-ray extinction models for fifteen dust candidates. These models, adapted for astrophysical analysis, and implemented in the Spex spectral fitting program, are used to reproduce the dust absorption features observed in the spectrum of the bright low mass X-ray binary GX 3+1 which is used as a background source. Results. With the simultaneous analysis of the two edges we test two different size distributions of dust: one corresponding to the standard Mathis-Rumpl-Nordsieck model and one considering larger grains (n(a) ∝ a −3.5 i with 0.005 < a 1 < 0.25 and 0.05 < a 2 < 0.5, respectively, with a the grain size). These distributions may be representative of the complex Galactic region towards this source. We find that up to 70% of dust is constituted by amorphous olivine. We discuss the crystallinity of the cosmic dust found along this line of sight. Both magnesium and silicon are highly depleted into dust (δ Z = 0.89 and 0.94, respectively) while their total abundance does not depart from solar values.Conclusions.

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Section: Continuumsupporting

confidence: 82%

Interstellar dust along the line of sight of GX 3+1

Rogantini

Costantini

Zeegers

et al. 2019

A&A

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“…The photoabsorption cross-sections below 10 keV are taken from the tables of Gatuzz et al (2015) 1 . They compile cross-sections obtained using different analytic methods (Bethe & Salpeter 1957), the R-matrix method (Gorczyca 2000;García et al 2005García et al , 2009Juett et al 2006;Witthoeft et al 2009Witthoeft et al , 2011Gorczyca et al 2013;Hasoglu et al 2014), semi-empirical fits (Verner & Yakovlev 1995), and experimental values (Kortright & Kim 2000). The tables cover energies from 0.01 keV to 10 keV with 650 000 logarithmically spaced steps, which results in a relative energy resolution of 10 −5 .…”

Section: Methodsmentioning

confidence: 99%

X-Ray Absorption in Young Core-collapse Supernova Remnants

Alp

Larsson

Fransson

et al. 2018

ApJ

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The material expelled by core-collapse supernova (SN) explosions absorbs X-rays from the central regions. We use SN models based on three-dimensional neutrino-driven explosions to estimate optical depths to the center of the explosion, compare different progenitor models, and investigate the effects of explosion asymmetries. The optical depths below 2 keV for progenitors with a remaining hydrogen envelope are expected to be high during the first century after the explosion due to photoabsorption. A typical optical depth is 100 t −2 4 E −2 , where t 4 is the time since the explosion in units of 10 000 days (∼27 years) and E the energy in units of keV. Compton scattering dominates above 50 keV, but the scattering depth is lower and reaches unity already at ∼1000 days at 1 MeV. The optical depths are approximately an order of magnitude lower for hydrogen-stripped progenitors. The metallicity of the SN ejecta is much higher than in the interstellar medium, which enhances photoabsorption and makes absorption edges stronger. These results are applicable to young SN remnants in general, but we explore the effects on observations of SN 1987A and the compact object in Cas A in detail. For SN 1987A, the absorption is high and the X-ray upper limits of ∼100 L on a compact object are approximately an order of magnitude less constraining than previous estimates using other absorption models. The details are presented in an accompanying paper (Alp et al. 2018). For the central compact object in Cas A, we find no significant effects of our more detailed absorption model on the inferred surface temperature.

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“…For this purpose, Wilms et al (2000) developed the TBabs and TBnew absorption models that have been widely used in the last decade. However, they only include neutral atomic species compromising their ability to render complex ISM spectral structures such as the O, Ne, and Mg K edges (Juett et al 2004(Juett et al , 2006Hasoglu et al 2014). Given this limitation, we have devised a new ISM X-ray absorption model-to be referred to as ISMabs-that compiles the most accurate atomic data available for neutrally, singly, and doubly ionized species of H, He, C, N, O, Ne, Mg, Si, S, Ar and Ca; in the case of iron, an experimental cross section has been chosen to Gorczyca (2000) and adjusted to astrophysical observations.…”

Section: Ismabs Photoabsorption Modelmentioning

confidence: 99%

“…In the case of magnesium, new photoabsorption cross sections by Bradshaw et al (1999) and h Sala & Greiner (2006). Hasoglu et al (2014) in warmabs were used to fit the Mg K edge in XMM-Newton spectra of the LMXB GS 1826-238 predicting that most of this element was in ionized form.…”

Section: Introductionmentioning

confidence: 99%

ISMabs: A COMPREHENSIVE X-RAY ABSORPTION MODEL FOR THE INTERSTELLAR MEDIUM

Gatuzz

García

Kallman

et al. 2015

ApJ

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We present an X-ray absorption model for the interstellar medium, to be referred to as ISMabs, that takes into account both neutral and ionized species of cosmically abundant elements, and includes the most accurate atomic data available. Using high-resolution spectra from eight X-ray binaries obtained with the Chandra High Energy Transmission Grating Spectrometer, we proceed to benchmark the atomic data in the model particularly in the neon K-edge region. Compared with previous photoabsorption models, which solely rely on neutral species, the inclusion of ions leads to improved spectral fits. Fit parameters comprise the column densities of abundant contributors that allow direct estimates of the ionization states. ISMabs is provided in the appropriate format to be implemented in widely used X-ray spectral fitting packages such as XSPEC, ISIS and SHERPA.

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K-Shell Photoabsorption of Magnesium Ions

Cited by 16 publications

References 50 publications

Interstellar dust along the line of sight of GX 3+1

Interstellar dust along the line of sight of GX 3+1

X-Ray Absorption in Young Core-collapse Supernova Remnants

ISMabs: A COMPREHENSIVE X-RAY ABSORPTION MODEL FOR THE INTERSTELLAR MEDIUM

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