Spectropolarimetry of the 3.4 micron Feature in the Diffuse ISM toward the Galactic Center Quintuplet Cluster

Details Spectropolarimetry of the 3.4 micron Feature in the Diffuse ISM toward the Galactic Center Quintuplet Cluster Spectropolarimetry of the 3.4 micron Feature in the Diffuse ISM toward the Galactic Center Quintuplet Cluster

2006-07-12

arxiv.org/abs/astro-ph/0607245v1

Astrophys.J.651:268-271,2006

Astronomy and Astrophysics

Astrophysics

11 pages, 1 figure. To appear in ApJ Oct. 20, 2006, volume 650

Scientific paper

10.1086/507462

Aliphatic hydrocarbons exhibit an absorption feature at 3.4 micron observed toward sources that sample diffuse regions of the interstellar medium. The absorbers responsible for this feature are assumed to reside in some component of interstellar dust, but the physical nature of the particles (size, shape, structure, etc.) is uncertain. Observations of interstellar polarization provide discrimination. Since the grains that carry the silicate absorption feature are known to be aligned, polarization across the 3.4 micron hydrocarbon feature can be used to test the silicate core-organic refractory mantle grain theory. Although the 3.4 micron feature has been observed to be devoid of polarization for one line of sight toward the Galactic center, a corresponding silicate polarization measurement for the same line of sight was not available. Here, we present spectropolarimetric observations toward GCS 3-II and GCS 3-IV toward the Galactic center, where the 9.7 micron silicate polarization has been previously observed. We show that polarization is not detected across the 3.4 micron feature to a limit of 0.06 +/- 0.13% (GCS 3-II) and 0.15 +/- 0.31% (GCS 3-IV), well below the lowest available prediction of polarization on the basis of the core-mantle model. We conclude that the hydrocarbons in the diffuse ISM do not reside on the same grains as the silicates and likely form a separate population of small grains.

Affiliated with

Also associated with

No associations

Rating

Spectropolarimetry of the 3.4 micron Feature in the Diffuse ISM toward the Galactic Center Quintuplet Cluster does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Spectropolarimetry of the 3.4 micron Feature in the Diffuse ISM toward the Galactic Center Quintuplet Cluster, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spectropolarimetry of the 3.4 micron Feature in the Diffuse ISM toward the Galactic Center Quintuplet Cluster will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-168966