On the discrepancy between the X-ray and UV absorption measurements of O VI in the local ISM

Gatuzz E, Garcia J, Kallman TR (2019)

Publication Type: Journal article

Publication year: 2019

Journal

Monthly Notices of the Royal Astronomical Society Oxford University Press

Book Volume: 483

Pages Range: L75-L79

Journal Issue: 1

DOI: 10.1093/mnrasl/sly223

Abstract

The total amount of OVI present in the interstellar medium ( ISM) obtained via absorption measurements in UV and X-ray spectra is currently in disagreement, with the latter being significantly larger ( by a factor of 10 or more) than the former. Previous works have proposed that the blend of the OVI K alpha line ( 22.032 angstrom) with the OII K beta-L12 line ( 22.04 angstrom) could account for the stronger absorption observed in the X-ray spectra. Here, we present a detailed study of the oxygen absorption in the local ISM, implementing our new model IGMabs which includes photoabsorption cross-sections of highly ionized species of abundant elements as well as turbulence broadening. By analysing high-resolution Chandra spectra of 13 low-mass X-ray binaries ( LMXBs) and 29 extragalactic sources, we have estimated the column densities of OI - OIII and from OVI - OVIII along multiple line-of-sights. We find that in most cases the OII K beta-L12 line accounts for <30 per cent of the total OVI K alpha + OII K beta. We conclude that the amount of OII predicted by our model is still insufficient to explain the discrepancy between X-ray and UV measurements of OVI column densities.

Authors with CRIS profile

Javier Garcia Dr.Karl-Remeis-Sternwarte Bamberg, Astronomisches Institut

Involved external institutions

National Aeronautics and Space Administration (NASA) US United States (USA) (US) European Southern Observatory (ESO) DE Germany (DE)

How to cite

APA:

Gatuzz, E., Garcia, J., & Kallman, T.R. (2019). On the discrepancy between the X-ray and UV absorption measurements of O VI in the local ISM. Monthly Notices of the Royal Astronomical Society, 483(1), L75-L79. https://dx.doi.org/10.1093/mnrasl/sly223

MLA:

Gatuzz, Efrain, Javier Garcia, and Timothy R. Kallman. "On the discrepancy between the X-ray and UV absorption measurements of O VI in the local ISM." Monthly Notices of the Royal Astronomical Society 483.1 (2019): L75-L79.

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