Can Supernovae from Runaway Stars Mimic the Signs of Absorbing “Supervirial” Gas?

The recent detection of large column density absorption lines from highly ionized gas in a few directions through the circumgalactic medium (CGM) of the Milky Way (MW) has been puzzling. The inferred temperature from these absorption lines far exceeds the virial temperature of the MW, and the column...

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Main Authors: Mukesh Singh Bisht, Projjwal Banerjee, Biman B. Nath, Yuri Shchekinov
Format: Article
Language:English
Published: IOP Publishing 2024-01-01
Series:The Astrophysical Journal
Subjects:
Online Access:https://doi.org/10.3847/1538-4357/ad77be
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author Mukesh Singh Bisht
Projjwal Banerjee
Biman B. Nath
Yuri Shchekinov
author_facet Mukesh Singh Bisht
Projjwal Banerjee
Biman B. Nath
Yuri Shchekinov
author_sort Mukesh Singh Bisht
collection DOAJ
description The recent detection of large column density absorption lines from highly ionized gas in a few directions through the circumgalactic medium (CGM) of the Milky Way (MW) has been puzzling. The inferred temperature from these absorption lines far exceeds the virial temperature of the MW, and the column densities are also too large to be easily explained. In this paper, we propose a novel idea to explain these observations and claim that they may not have originated from the CGM, but from a totally different type of source, namely, stellar ejecta from supernovae (SNe) above the Galactic disk that happen to lie in the line of sight to the background quasars. About ∼20% of massive OB stars (progenitors of core-collapse supernovae) are known to be runaway stars that have high ejection velocities near the Galactic plane and can end up exploding as SNe above the Galactic disk. We show that the associated reverse shock in the supernova remnant in the early nonradiative phase can heat the ejecta to temperatures of ≳10 ^7 K and can naturally explain the observed high column density of ions in the observed “supervirial” phase along with α -enriched supersolar abundance that is typical of core-collapse supernovae. However, SNe from runaway stars has a covering fraction of ≲0.7% and thus can only explain the observations along limited sightlines.
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spelling doaj-art-a892537d0a564aa9b673f225d867e4c32025-08-20T01:54:16ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-0197512610.3847/1538-4357/ad77beCan Supernovae from Runaway Stars Mimic the Signs of Absorbing “Supervirial” Gas?Mukesh Singh Bisht0https://orcid.org/0000-0002-1497-4645Projjwal Banerjee1https://orcid.org/0000-0002-6389-2697Biman B. Nath2https://orcid.org/0000-0003-1922-9406Yuri Shchekinov3https://orcid.org/0000-0002-3463-7339Raman Research Institute Bengaluru —560080, IndiaDepartment of Physics, Indian Institute of Technology Palakkad , Kerala, IndiaRaman Research Institute Bengaluru —560080, IndiaRaman Research Institute Bengaluru —560080, IndiaThe recent detection of large column density absorption lines from highly ionized gas in a few directions through the circumgalactic medium (CGM) of the Milky Way (MW) has been puzzling. The inferred temperature from these absorption lines far exceeds the virial temperature of the MW, and the column densities are also too large to be easily explained. In this paper, we propose a novel idea to explain these observations and claim that they may not have originated from the CGM, but from a totally different type of source, namely, stellar ejecta from supernovae (SNe) above the Galactic disk that happen to lie in the line of sight to the background quasars. About ∼20% of massive OB stars (progenitors of core-collapse supernovae) are known to be runaway stars that have high ejection velocities near the Galactic plane and can end up exploding as SNe above the Galactic disk. We show that the associated reverse shock in the supernova remnant in the early nonradiative phase can heat the ejecta to temperatures of ≳10 ^7 K and can naturally explain the observed high column density of ions in the observed “supervirial” phase along with α -enriched supersolar abundance that is typical of core-collapse supernovae. However, SNe from runaway stars has a covering fraction of ≲0.7% and thus can only explain the observations along limited sightlines.https://doi.org/10.3847/1538-4357/ad77beCircumgalactic mediumSupernova remnantsRunaway starsHalo starsMilky Way Galaxy
spellingShingle Mukesh Singh Bisht
Projjwal Banerjee
Biman B. Nath
Yuri Shchekinov
Can Supernovae from Runaway Stars Mimic the Signs of Absorbing “Supervirial” Gas?
The Astrophysical Journal
Circumgalactic medium
Supernova remnants
Runaway stars
Halo stars
Milky Way Galaxy
title Can Supernovae from Runaway Stars Mimic the Signs of Absorbing “Supervirial” Gas?
title_full Can Supernovae from Runaway Stars Mimic the Signs of Absorbing “Supervirial” Gas?
title_fullStr Can Supernovae from Runaway Stars Mimic the Signs of Absorbing “Supervirial” Gas?
title_full_unstemmed Can Supernovae from Runaway Stars Mimic the Signs of Absorbing “Supervirial” Gas?
title_short Can Supernovae from Runaway Stars Mimic the Signs of Absorbing “Supervirial” Gas?
title_sort can supernovae from runaway stars mimic the signs of absorbing supervirial gas
topic Circumgalactic medium
Supernova remnants
Runaway stars
Halo stars
Milky Way Galaxy
url https://doi.org/10.3847/1538-4357/ad77be
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