Query : 2010A&A...518A..31V

2010A&A...518A..31V - Astronomy and Astrophysics, volume 518, A31-31 (2010/7-2)

Spatial distribution of interstellar dust in the sun's vicinity. Comparison with neutral sodium-bearing gas.


Abstract (from CDS):

3D tomography of the interstellar dust and gas may be useful in many respects, from the physical and chemical evolution of the interstellar medium itself to foreground decontamination of the cosmic microwave background, or various studies of the environments of specific objects. However, while spectral data cubes of the galactic emission become increasingly precise, the information on the distance to the emitting regions has not progressed as well and relies essentially on the galactic rotation curve. Our goal here is to bring more precise information on the distance to nearby interstellar dust and gas clouds within 250pc. We apply the best available calibration methods to a carefully screened set of stellar Stroemgren photometry data for targets possessing a Hipparcos parallax and spectral type classification. We combine the derived interstellar extinctions and the parallax distances for about 6000 stars to build a 3D tomography of the local dust. We use an inversion method based on a regularized Bayesian approach and a least squares criterion, optimized for this specific data set. We apply the same inversion technique to a totally independent set of neutral sodium absorption data available for about 1700 target stars. We obtain 3D maps of the opacity and the distance to the main dust-bearing clouds within 250pc and identify in those maps well-known dark clouds and high galactic more diffuse entities. We calculate the integrated extinction between the Sun and the cube boundary and compare this with the total galactic extinction derived from infrared 2D maps. The two quantities reach similar values at high latitudes, as expected if the local dust content is satisfyingly reproduced and the dust is closer than 250pc. Those maps show a larger high latitude dust opacity in the North compared to the South, reinforcing earlier evidences. Interestingly the gas maps do not show the same asymmetry, suggesting a polar asymmetry of the dust to gas ratio at small distances. We compare the opacity distribution with the 3D distribution of interstellar neutral sodium resulting from the inversion of sodium columns. We discuss the similarities and discrepancies and the influence of data set limitations. Finally we discuss the potential improvements of those 3D maps.

Abstract Copyright:

Journal keyword(s): ISM: clouds - dust, extinction - local insterstellar matter

Simbad objects: 12

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Number of rows : 12
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 NAME Loop III SR? 01 12 +78.3           ~ 87 1
2 NAME Lindblad Ring DNe 02 16 45 +64 21.5           ~ 42 0
3 NAME Eridanus Shell sh 02 17 31 +07 49.6           ~ 47 0
4 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 4093 0
5 NAME Vela Supershell sh 07 40 -22.           ~ 26 0
6 NAME Coalsack Nebula DNe 12 31 19 -63 44.6           ~ 250 0
7 NAME Lupus Complex SFR 16 03 -38.1           ~ 642 0
8 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3446 1
9 NAME Sco-Oph Region reg 16 30.0 -21 00           ~ 73 0
10 NAME Loop 2 SR? 23 25 +26.5           ~ 77 1
11 NAME Gould Belt PoG ~ ~           ~ 832 1
12 NAME Local Bubble ISM ~ ~           ~ 821 0

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