Very Extended X-ray and $H-\alpha$ Emission in M82: Implications for the Superwind Phenomenon
We discuss the properties and implications of a 3.7x0.9 kpc region of spatially-coincident X-ray and H-alpha emission about 11.6 kpc to the north of the galaxy M82 previously discussed by Devine and Bally (1999). The PSPC X-ray spectrum is fit by thermal plasma (kT=0.80+-0.17 keV) absorbed by only t...
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ftcern:oai:cds.cern.ch:384970 2023-05-15T13:20:24+02:00 Very Extended X-ray and $H-\alpha$ Emission in M82: Implications for the Superwind Phenomenon Lehnert, M D Heckman, T M Weaver, K A 1999 https://doi.org/10.1086/307762 http://cds.cern.ch/record/384970 eng eng doi:10.1086/307762 http://cds.cern.ch/record/384970 astro-ph/9904227 oai:cds.cern.ch:384970 Astrophysics and Astronomy 1999 ftcern https://doi.org/10.1086/307762 2018-07-28T03:59:14Z We discuss the properties and implications of a 3.7x0.9 kpc region of spatially-coincident X-ray and H-alpha emission about 11.6 kpc to the north of the galaxy M82 previously discussed by Devine and Bally (1999). The PSPC X-ray spectrum is fit by thermal plasma (kT=0.80+-0.17 keV) absorbed by only the Galactic foreground column density. We evaluate the relationship of the X-ray/H-alpha ridge to the M82 superwind. The main properties of the X-ray emission can all be explained as being due to shock-heating driven as the superwind encounters a massive ionized cloud in the halo of M82. This encounter drives a slow shock into the cloud, which contributes to the excitation of the observed H-alpha emission. At the same time, a fast bow-shock develops in the superwind just upstream of the cloud, and this produces the observed X-ray emission. This interpretation would imply that the superwind has an outflow speed of roughly 800 km/s, consistent with indirect estimates based on its general X-ray properties and the kinematics of the inner kpc-scale region of H-alpha filaments. The gas in the M82 ridge is roughly two orders-of-magnitude hotter than the minimum "escape temperature" at this radius, so this gas will not be retained by M82. (abridged) Other/Unknown Material alpha ridge CERN Document Server (CDS) Alpha Ridge ENVELOPE(-120.000,-120.000,85.500,85.500) The Astrophysical Journal 523 2 575 584 |
institution |
Open Polar |
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CERN Document Server (CDS) |
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language |
English |
topic |
Astrophysics and Astronomy |
spellingShingle |
Astrophysics and Astronomy Lehnert, M D Heckman, T M Weaver, K A Very Extended X-ray and $H-\alpha$ Emission in M82: Implications for the Superwind Phenomenon |
topic_facet |
Astrophysics and Astronomy |
description |
We discuss the properties and implications of a 3.7x0.9 kpc region of spatially-coincident X-ray and H-alpha emission about 11.6 kpc to the north of the galaxy M82 previously discussed by Devine and Bally (1999). The PSPC X-ray spectrum is fit by thermal plasma (kT=0.80+-0.17 keV) absorbed by only the Galactic foreground column density. We evaluate the relationship of the X-ray/H-alpha ridge to the M82 superwind. The main properties of the X-ray emission can all be explained as being due to shock-heating driven as the superwind encounters a massive ionized cloud in the halo of M82. This encounter drives a slow shock into the cloud, which contributes to the excitation of the observed H-alpha emission. At the same time, a fast bow-shock develops in the superwind just upstream of the cloud, and this produces the observed X-ray emission. This interpretation would imply that the superwind has an outflow speed of roughly 800 km/s, consistent with indirect estimates based on its general X-ray properties and the kinematics of the inner kpc-scale region of H-alpha filaments. The gas in the M82 ridge is roughly two orders-of-magnitude hotter than the minimum "escape temperature" at this radius, so this gas will not be retained by M82. (abridged) |
author |
Lehnert, M D Heckman, T M Weaver, K A |
author_facet |
Lehnert, M D Heckman, T M Weaver, K A |
author_sort |
Lehnert, M D |
title |
Very Extended X-ray and $H-\alpha$ Emission in M82: Implications for the Superwind Phenomenon |
title_short |
Very Extended X-ray and $H-\alpha$ Emission in M82: Implications for the Superwind Phenomenon |
title_full |
Very Extended X-ray and $H-\alpha$ Emission in M82: Implications for the Superwind Phenomenon |
title_fullStr |
Very Extended X-ray and $H-\alpha$ Emission in M82: Implications for the Superwind Phenomenon |
title_full_unstemmed |
Very Extended X-ray and $H-\alpha$ Emission in M82: Implications for the Superwind Phenomenon |
title_sort |
very extended x-ray and $h-\alpha$ emission in m82: implications for the superwind phenomenon |
publishDate |
1999 |
url |
https://doi.org/10.1086/307762 http://cds.cern.ch/record/384970 |
long_lat |
ENVELOPE(-120.000,-120.000,85.500,85.500) |
geographic |
Alpha Ridge |
geographic_facet |
Alpha Ridge |
genre |
alpha ridge |
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alpha ridge |
op_relation |
doi:10.1086/307762 http://cds.cern.ch/record/384970 astro-ph/9904227 oai:cds.cern.ch:384970 |
op_doi |
https://doi.org/10.1086/307762 |
container_title |
The Astrophysical Journal |
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523 |
container_issue |
2 |
container_start_page |
575 |
op_container_end_page |
584 |
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1766353203300925440 |