| Issue |
A&A
Volume 694, February 2025
|
|
|---|---|---|
| Article Number | L13 | |
| Number of page(s) | 3 | |
| Section | Letters to the Editor | |
| DOI | https://doi.org/10.1051/0004-6361/202453133 | |
| Published online | 13 February 2025 | |
Letter to the Editor
New insights with XRISM and Cloudy: A novel column density diagnostic
1
Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
2
Royal Observatory of Belgium, Ringlaan 3, B-1180 Brussels, Belgium
3
Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210, Japan
4
University of Kentucky, 506 Library Drive, Lexington, KY 40506, USA
⋆ Corresponding author; cgunasekera@stsci.edu
Received:
22
November
2024
Accepted:
18
January
2025
Aims. We present a simple yet powerful column density diagnostic for plasmas enabled by X-ray microcalorimeter observations.
Methods. With the recent developments of the spectral simulation code CLOUDY, inspired by the high spectral resolution of the X-Ray Imaging and Spectroscopy Mission (XRISM) and the Advanced Telescope for High Energy Astrophysics (Athena), we make predictions for the intensity ratio of the resolved fine-structure lines Lyα1 and Lyα2 of H-like ions.
Results. We show that this ratio can be observationally constrained and used as a plasma column density indicator. We demonstrate this with an XRISM observation of the high-mass X-ray binary Centaurus X-3.
Conclusions. This diagnostic is useful for a wide range of X-ray emitting plasmas that are either collisionally or radiatively ionized.
Key words: atomic processes / radiative transfer / X-rays: binaries
© The Authors 2025
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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