2015A&A...584A..93J


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.05CEST09:48:49

2015A&A...584A..93J - Astronomy and Astrophysics, volume 584A, 93-93 (2015/12-1)

Galactic cold cores. V. Dust opacity.

JUVELA M., RISTORCELLI I., MARSHALL D.J., MONTILLAUD J., PELKONEN V.-M., YSARD N., McGEHEE P., PALADINI R., PAGANI L., MALINEN J., RIVERA-INGRAHAM A., LEFEVRE C., TOTH L.V., MONTIER L.A., BERNARD J.-P. and MARTIN P.

Abstract (from CDS):

The project Galactic Cold Cores has carried out Herschel photometric observations of interstellar clouds where the Planck satellite survey has located cold and compact clumps. The sources represent different stages of cloud evolution from starless clumps to protostellar cores and are located in different Galactic environments. We examine this sample of 116 Herschel fields to estimate the submillimetre dust opacity and to search for variations that might be attributed to the evolutionary stage of the sources or to environmental factors, including the location within the Galaxy. The submillimetre dust opacity was derived from Herschel data, and near-infrared observations of the reddening of background stars are converted into near-infrared optical depth. We investigated the systematic errors affecting these parameters and used modelling to correct for the expected biases. The ratio of 250µm and J band opacities is correlated with the Galactic location and the star formation activity. We searched for local variations in the ratio τ(250µm)/τ(J) using the correlation plots and opacity ratio maps. We find a median ratio of τ(250µm)/τ(J)=(1.6±0.2)x10–3, which is more than three times the mean value reported for the diffuse medium. Assuming an opacity spectral index β=1.8 instead of β=2.0, the value would be lower by ∼30%. No significant systematic variation is detected with Galactocentric distance or with Galactic height. Examination of the τ(250µm)/τ(J) maps reveals six fields with clear indications of a local increase of submillimetre opacity of up to τ(250µm)/τ(J)∼4x10–3 towards the densest clumps. These are all nearby fields with spatially resolved clumps of high column density. We interpret the increase in the far-infrared opacity as a sign of grain growth in the densest and coldest regions of interstellar clouds.

Abstract Copyright:

Journal keyword(s): ISM: clouds - infrared: ISM - submillimeter: ISM - dust, extinction - stars: formation - stars: protostars

VizieR on-line data: <Available at CDS (J/A+A/584/A93): table1.dat tablee1.dat>

Simbad objects: 12

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Number of rows : 12

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 LDN 1506 DNe 04 20.0 +25 17           ~ 70 0
2 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 3478 0
3 NGC 1909 RNe 05 02 -07.9           ~ 31 0
4 NAME Ori A MoC 05 38 -07.1           ~ 2675 0
5 NAME Ori B MoC 05 41 43.0 -01 54 44           ~ 1164 0
6 NAME Vela XYZ Rad 08 34.0 -45 50           ~ 1110 2
7 NAME Witch Cld 10 50 21 +83 27.8           ~ 3 0
8 NAME Polaris Flare MoC 11 00 14.8 +86 10 52           ~ 162 1
9 LDN 134 MoC 15 53 36.3 -04 35 26           ~ 194 0
10 LDN 183 MoC 15 54 12.2 -02 49 42           ~ 682 1
11 LDN 1746 DNe 17 11.3 -27 22           ~ 108 0
12 NAME the Pipe Nebula DNe 17 30 -25.0           ~ 333 1

    Equat.    Gal    SGal    Ecl

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2020.07.05-09:48:49

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