Where is the Supervirial hot gas? I: A pilot study with sightlines to Galactic X-ray binaries

Fuente: arXiv
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Main Authors: Lara-DI, Armando, Krongold, Yair, Mathur, Smita, Roy, Manami, McClain, Rebecca L., Das, Sanskriti, Gupta, Anjali
Format: Preprint
Published: 2024
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author Lara-DI, Armando
Krongold, Yair
Mathur, Smita
Roy, Manami
McClain, Rebecca L.
Das, Sanskriti
Gupta, Anjali
author_facet Lara-DI, Armando
Krongold, Yair
Mathur, Smita
Roy, Manami
McClain, Rebecca L.
Das, Sanskriti
Gupta, Anjali
contents Hot, \logT\ $\sim$ 7.5, gas was recently discovered in the Milky Way in extragalactic sightlines. In order to determine its location, here we present sightlines to Galactic X-ray binaries (XRBs) passing through the Interstellar Medium (ISM). In this pilot study we investigate absorption features of \SXVI, \SiXIV, and \NeX\ in the spectra of three XRBs, namely 4U 1735-44, 4U 1820-30, and Cyg X-2, using Chandra High Energy Transmission Grating archival observations. We do not detect any of these lines. {We determine the 2$σ$ upper limit for the equivalent widths of the undetected absorption lines and the column densities of the corresponding ions.} We note that the 2$σ$ upper limits for \SXVI\ \Ka\ and \SiXIV\ \Ka\ are an order of magnitude smaller than those previously detected in the extragalactic sightlines. Our finding suggests that if any gas at \logT\ $>7$ is present in the Galactic ISM, it is unlikely to be ubiquitous. This is an important result because it implies that \SXVI, \SiXIV\ {and \NeX\ }absorption detected in extragalactic sightlines is not from the ISM, but is likely from a hot gas phase in the extraplanar region beyond the ISM or in the extended CGM.
format Preprint
id arxiv_https___arxiv_org_abs_2407_16790
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Where is the Supervirial hot gas? I: A pilot study with sightlines to Galactic X-ray binaries
Lara-DI, Armando
Krongold, Yair
Mathur, Smita
Roy, Manami
McClain, Rebecca L.
Das, Sanskriti
Gupta, Anjali
Astrophysics of Galaxies
High Energy Astrophysical Phenomena
Hot, \logT\ $\sim$ 7.5, gas was recently discovered in the Milky Way in extragalactic sightlines. In order to determine its location, here we present sightlines to Galactic X-ray binaries (XRBs) passing through the Interstellar Medium (ISM). In this pilot study we investigate absorption features of \SXVI, \SiXIV, and \NeX\ in the spectra of three XRBs, namely 4U 1735-44, 4U 1820-30, and Cyg X-2, using Chandra High Energy Transmission Grating archival observations. We do not detect any of these lines. {We determine the 2$σ$ upper limit for the equivalent widths of the undetected absorption lines and the column densities of the corresponding ions.} We note that the 2$σ$ upper limits for \SXVI\ \Ka\ and \SiXIV\ \Ka\ are an order of magnitude smaller than those previously detected in the extragalactic sightlines. Our finding suggests that if any gas at \logT\ $>7$ is present in the Galactic ISM, it is unlikely to be ubiquitous. This is an important result because it implies that \SXVI, \SiXIV\ {and \NeX\ }absorption detected in extragalactic sightlines is not from the ISM, but is likely from a hot gas phase in the extraplanar region beyond the ISM or in the extended CGM.
title Where is the Supervirial hot gas? I: A pilot study with sightlines to Galactic X-ray binaries
topic Astrophysics of Galaxies
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2407.16790