The distance and properties of hydrogen clouds in the Leading Arm of the Magellanic System

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Abstract

© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.We present a high-resolution study of five high-velocity clouds in the Magellanic Leading Arm region. This is a follow-up study of our widefield Parkes survey of the region in order to probe the multiphase structures of the clouds and to give an insight to their origin, evolution and distance. High-resolution data were obtained from the Australia Telescope Compact Array. By combining with single-dish data from the Galactic All-Sky Survey, we are able to probe compact and diffuse emission simultaneously. We identify resolved and unresolved clumps. Physical parameters were derived for both diffuse structure and compact clumps. The latter are cold with typical velocity linewidths of 5 km s-1. We find a gradient in thermal halo pressure, hydrogen density and HI column density of high-velocity clouds as a function of Galactic latitude. This is possibly the first observational evidence of varying distance in the Leading Arm region, with the leading part of the Leading Arm (LA II and III) probably being closer to the Galactic disc than the trailing end (LA I).
Original languageEnglish
Pages (from-to)892-907
Number of pages16
JournalMonthly Notices of the Royal Astronomical Society
Volume461
Issue number1
DOIs
Publication statusPublished - 2016

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hydrogen clouds
hydrogen
clumps
probe
probes
parabolic reflectors
high resolution
halos
telescopes
gradients

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@article{bcb2ee5f09da4b18b724c0d3b90daef7,
title = "The distance and properties of hydrogen clouds in the Leading Arm of the Magellanic System",
abstract = "{\circledC} 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.We present a high-resolution study of five high-velocity clouds in the Magellanic Leading Arm region. This is a follow-up study of our widefield Parkes survey of the region in order to probe the multiphase structures of the clouds and to give an insight to their origin, evolution and distance. High-resolution data were obtained from the Australia Telescope Compact Array. By combining with single-dish data from the Galactic All-Sky Survey, we are able to probe compact and diffuse emission simultaneously. We identify resolved and unresolved clumps. Physical parameters were derived for both diffuse structure and compact clumps. The latter are cold with typical velocity linewidths of 5 km s-1. We find a gradient in thermal halo pressure, hydrogen density and HI column density of high-velocity clouds as a function of Galactic latitude. This is possibly the first observational evidence of varying distance in the Leading Arm region, with the leading part of the Leading Arm (LA II and III) probably being closer to the Galactic disc than the trailing end (LA I).",
author = "Bi-Qing For and Lister Staveley-Smith and N.M. McClure-Griffiths and Tobias Westmeier and Kenji Bekki",
year = "2016",
doi = "10.1093/mnras/stw1364",
language = "English",
volume = "461",
pages = "892--907",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "0035-8711",
publisher = "OXFORD UNIV PRESS UNITED KINGDOM",
number = "1",

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TY - JOUR

T1 - The distance and properties of hydrogen clouds in the Leading Arm of the Magellanic System

AU - For, Bi-Qing

AU - Staveley-Smith, Lister

AU - McClure-Griffiths, N.M.

AU - Westmeier, Tobias

AU - Bekki, Kenji

PY - 2016

Y1 - 2016

N2 - © 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.We present a high-resolution study of five high-velocity clouds in the Magellanic Leading Arm region. This is a follow-up study of our widefield Parkes survey of the region in order to probe the multiphase structures of the clouds and to give an insight to their origin, evolution and distance. High-resolution data were obtained from the Australia Telescope Compact Array. By combining with single-dish data from the Galactic All-Sky Survey, we are able to probe compact and diffuse emission simultaneously. We identify resolved and unresolved clumps. Physical parameters were derived for both diffuse structure and compact clumps. The latter are cold with typical velocity linewidths of 5 km s-1. We find a gradient in thermal halo pressure, hydrogen density and HI column density of high-velocity clouds as a function of Galactic latitude. This is possibly the first observational evidence of varying distance in the Leading Arm region, with the leading part of the Leading Arm (LA II and III) probably being closer to the Galactic disc than the trailing end (LA I).

AB - © 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.We present a high-resolution study of five high-velocity clouds in the Magellanic Leading Arm region. This is a follow-up study of our widefield Parkes survey of the region in order to probe the multiphase structures of the clouds and to give an insight to their origin, evolution and distance. High-resolution data were obtained from the Australia Telescope Compact Array. By combining with single-dish data from the Galactic All-Sky Survey, we are able to probe compact and diffuse emission simultaneously. We identify resolved and unresolved clumps. Physical parameters were derived for both diffuse structure and compact clumps. The latter are cold with typical velocity linewidths of 5 km s-1. We find a gradient in thermal halo pressure, hydrogen density and HI column density of high-velocity clouds as a function of Galactic latitude. This is possibly the first observational evidence of varying distance in the Leading Arm region, with the leading part of the Leading Arm (LA II and III) probably being closer to the Galactic disc than the trailing end (LA I).

U2 - 10.1093/mnras/stw1364

DO - 10.1093/mnras/stw1364

M3 - Article

VL - 461

SP - 892

EP - 907

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 1

ER -