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Main Authors: Nandakumar, Meera, Roy, Nirupam, Jog, Chanda J., Menten, Karl M.
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2401.08168
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author Nandakumar, Meera
Roy, Nirupam
Jog, Chanda J.
Menten, Karl M.
author_facet Nandakumar, Meera
Roy, Nirupam
Jog, Chanda J.
Menten, Karl M.
contents A massive molecular cloud complex represents local gravitational potential that can constrain the vertical distribution of surrounding stars and gas. This pinching effect results in the local corrugation of the scale height of stars and gas which is in addition to the global corrugation of the mid-plane of the disc. For the first time, we report observational evidence for this pinching on the \HI vertical structures in the Galactic region ($20^{\circ}< l<40^{\circ}$), also called W41--W44 region. The \HI vertical distribution is modelled by a double Gaussian profile that physically represents a narrow dense gas distribution confined to the mid-plane embedded in a wider diffuse \HI. We find that the estimate of the \HI scale height distribution of wider components, shows corrugated structures at the locations of molecular complexes, as theoretically predicted in literature. While the narrow component is less affected by the pinching, we found a hint of the disc being disrupted by the active dynamics in the local environment of the complex, e.g., supernova explosions. Molecular complexes of mass of several $10^6$ solar mass, associated with the mini-starburst region W43 and the supernova remnant W41 show the strongest evidence for the pinching; here a broad trough, with an average width of $\sim400$ pc and height $\sim300$ pc, in the disc thickness of the wider component is prominently visible. Searching for similar effect on the stars as well as in the location of other complexes in the Milky Way and other galaxies will be useful to establish this phenomenon more firmly.
format Preprint
id arxiv_https___arxiv_org_abs_2401_08168
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Observational evidence for local vertical constraining of \HI by molecular cloud complexes
Nandakumar, Meera
Roy, Nirupam
Jog, Chanda J.
Menten, Karl M.
Astrophysics of Galaxies
A massive molecular cloud complex represents local gravitational potential that can constrain the vertical distribution of surrounding stars and gas. This pinching effect results in the local corrugation of the scale height of stars and gas which is in addition to the global corrugation of the mid-plane of the disc. For the first time, we report observational evidence for this pinching on the \HI vertical structures in the Galactic region ($20^{\circ}< l<40^{\circ}$), also called W41--W44 region. The \HI vertical distribution is modelled by a double Gaussian profile that physically represents a narrow dense gas distribution confined to the mid-plane embedded in a wider diffuse \HI. We find that the estimate of the \HI scale height distribution of wider components, shows corrugated structures at the locations of molecular complexes, as theoretically predicted in literature. While the narrow component is less affected by the pinching, we found a hint of the disc being disrupted by the active dynamics in the local environment of the complex, e.g., supernova explosions. Molecular complexes of mass of several $10^6$ solar mass, associated with the mini-starburst region W43 and the supernova remnant W41 show the strongest evidence for the pinching; here a broad trough, with an average width of $\sim400$ pc and height $\sim300$ pc, in the disc thickness of the wider component is prominently visible. Searching for similar effect on the stars as well as in the location of other complexes in the Milky Way and other galaxies will be useful to establish this phenomenon more firmly.
title Observational evidence for local vertical constraining of \HI by molecular cloud complexes
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2401.08168