A cold nearby cloud inside the local bubble

David M. Meyer; J. T. Lauroesch; Carl Heiles; J. E.G. Peek; Kyle Engelhorn

doi:10.1086/508658

A cold nearby cloud inside the local bubble

David M. Meyer^*, J. T. Lauroesch, Carl Heiles, J. E.G. Peek, Kyle Engelhorn

^*Corresponding author for this work

Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

36 Scopus citations

Abstract

The high-latitude Galactic H I cloud toward the extragalactic radio source 3C 225 is characterized by very narrow 21 cm emission and absorption indicative of a very low H I spin temperature of about 20 K. Through high-resolution optical spectroscopy, we report the detection of strong, very narrow Na I absorption corresponding to this cloud toward a number of nearby stars. Assuming that the turbulent H I and Na I motions are similar, we derive a cloud temperature of 20_-8⁺⁶ K (in complete agreement with the 21 cm results) and a line-of-sight turbulent velocity of 0.37 ±0.08 km s^-1 from a comparison of the H I and Na I absorption line widths, We also place a firm upper limit of 45 pc on the distance of the cloud, which situates it well inside the Local Bubble in this direction and makes it the nearest known cold diffuse cloud discovered to date.

Original language	English (US)
Pages (from-to)	L67-L70
Journal	Astrophysical Journal
Volume	650
Issue number	1 II
DOIs	https://doi.org/10.1086/508658
State	Published - Oct 10 2006

Keywords

ISM: atoms
ISM: clouds
ISM: structure
Solar neighborhood

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1086/508658

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@article{d65dc44ef6ec4c9d82a38a6a3cad5287,

title = "A cold nearby cloud inside the local bubble",

abstract = "The high-latitude Galactic H I cloud toward the extragalactic radio source 3C 225 is characterized by very narrow 21 cm emission and absorption indicative of a very low H I spin temperature of about 20 K. Through high-resolution optical spectroscopy, we report the detection of strong, very narrow Na I absorption corresponding to this cloud toward a number of nearby stars. Assuming that the turbulent H I and Na I motions are similar, we derive a cloud temperature of 20-8+6 K (in complete agreement with the 21 cm results) and a line-of-sight turbulent velocity of 0.37 ±0.08 km s-1 from a comparison of the H I and Na I absorption line widths, We also place a firm upper limit of 45 pc on the distance of the cloud, which situates it well inside the Local Bubble in this direction and makes it the nearest known cold diffuse cloud discovered to date.",

keywords = "ISM: atoms, ISM: clouds, ISM: structure, Solar neighborhood",

author = "Meyer, {David M.} and Lauroesch, {J. T.} and Carl Heiles and Peek, {J. E.G.} and Kyle Engelhorn",

note = "Funding Information: It is a pleasure to thank Daryl Willmarth for his assistance with the Kitt Peak National Observatory observations (which included deicing the coud{\'e} feed telescope enclosure after an immobilizing March blizzard). We are also grateful to the anonymous referee whose helpful comments improved this Letter. C. H. acknowledges support from NSF grant AST 04-06987.",

year = "2006",

month = oct,

day = "10",

doi = "10.1086/508658",

language = "English (US)",

volume = "650",

pages = "L67--L70",

journal = "Astrophysical Journal",

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T1 - A cold nearby cloud inside the local bubble

AU - Meyer, David M.

AU - Lauroesch, J. T.

AU - Heiles, Carl

AU - Peek, J. E.G.

AU - Engelhorn, Kyle

N1 - Funding Information: It is a pleasure to thank Daryl Willmarth for his assistance with the Kitt Peak National Observatory observations (which included deicing the coudé feed telescope enclosure after an immobilizing March blizzard). We are also grateful to the anonymous referee whose helpful comments improved this Letter. C. H. acknowledges support from NSF grant AST 04-06987.

PY - 2006/10/10

Y1 - 2006/10/10

N2 - The high-latitude Galactic H I cloud toward the extragalactic radio source 3C 225 is characterized by very narrow 21 cm emission and absorption indicative of a very low H I spin temperature of about 20 K. Through high-resolution optical spectroscopy, we report the detection of strong, very narrow Na I absorption corresponding to this cloud toward a number of nearby stars. Assuming that the turbulent H I and Na I motions are similar, we derive a cloud temperature of 20-8+6 K (in complete agreement with the 21 cm results) and a line-of-sight turbulent velocity of 0.37 ±0.08 km s-1 from a comparison of the H I and Na I absorption line widths, We also place a firm upper limit of 45 pc on the distance of the cloud, which situates it well inside the Local Bubble in this direction and makes it the nearest known cold diffuse cloud discovered to date.

AB - The high-latitude Galactic H I cloud toward the extragalactic radio source 3C 225 is characterized by very narrow 21 cm emission and absorption indicative of a very low H I spin temperature of about 20 K. Through high-resolution optical spectroscopy, we report the detection of strong, very narrow Na I absorption corresponding to this cloud toward a number of nearby stars. Assuming that the turbulent H I and Na I motions are similar, we derive a cloud temperature of 20-8+6 K (in complete agreement with the 21 cm results) and a line-of-sight turbulent velocity of 0.37 ±0.08 km s-1 from a comparison of the H I and Na I absorption line widths, We also place a firm upper limit of 45 pc on the distance of the cloud, which situates it well inside the Local Bubble in this direction and makes it the nearest known cold diffuse cloud discovered to date.

KW - ISM: atoms

KW - ISM: clouds

KW - ISM: structure

KW - Solar neighborhood

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DO - 10.1086/508658

M3 - Article

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SP - L67-L70

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1 II

ER -

A cold nearby cloud inside the local bubble

Abstract

Keywords

ASJC Scopus subject areas

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