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ID 34750
file
creator
Yagi, Masafumi
Komiyama, Yutaka
subject
galaxies: individual (Magellanic Stream)
Galaxy: halo
intergalactic medium
NDC
Astronomy. Space sciences
abstract
From H alpha narrowband observations, we identified three H alpha emitting regions in the direction of Magellanic Stream IV (MS IV). They consist of three parallel filaments of 2 arcmin width and 6-30 arcmin length at 12 arcmin intervals. Their mean surface brightness (SB) is similar to 2 x 10(-18) erg s(-1) cm(-2) arcsec(-2). Because of their low SB, the regions were not detected in previous Ha surveys. In the HI map, the position of the filaments overlap MS, suggesting that they are parts of the MS, but there also exists a local HI structure. If the filaments are associated with the MS, the sizes are 30 pc x 100-500 pc. The filaments lie at the leading edge of a downstream cloud, which supports shock heating and its propagation (shock cascade) model for the ionizing source. If they are local objects, on the other hand, Fossil Stromgren Trails of more than two stars is a possible interpretation, and the sizes would be 0.1 pc x 0.3-1.5 pc at 180 pc distance. The positional information of the H alpha filaments presented in this Letter enables future spectroscopic observations to clarify their nature.
journal title
Astrophysical Journal Letters
volume
Volume 749
issue
Issue 1
start page
L2
date of issued
2012
publisher
IOP Publishing Ltd
issn
2041-8205
ncid
publisher doi
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
publisher
rights
(c) 2012. The American Astronomical Society. All rights reserved.
relation url
department
Hiroshima Astrophysical Science Center