2018A&A...610A..16G


C.D.S. - SIMBAD4 rel 1.7 - 2020.08.04CEST22:53:25

2018A&A...610A..16G - Astronomy and Astrophysics, volume 610A, 16-16 (2018/2-1)

Dust models compatible with Planck intensity and polarization data in translucent lines of sight.

GUILLET V., FANCIULLO L., VERSTRAETE L., BOULANGER F., JONES A.P., MIVILLE-DESCHENES M.-A., YSARD N., LEVRIER F. and ALVES M.

Abstract (from CDS):

Context. Current dust models are challenged by the dust properties inferred from the analysis of Planck observations in total and polarized emission.
Aims. We propose new dust models compatible with polarized and unpolarized data in extinction and emission for translucent lines of sight (0.5<AV<2.5).
Methods. We amended the DustEM tool to model polarized extinction and emission. We fit the spectral dependence of the mean extinction, polarized extinction, total and polarized spectral energy distributions (SEDs) with polycyclic aromatic hydrocarbons, astrosilicate and amorphous carbon (a-C) grains. The astrosilicate population is aligned along the magnetic field lines, while the a-C population may be aligned or not.
Results. With their current optical properties, oblate astrosilicate grains are not emissive enough to reproduce the emission to extinction polarization ratio P353/pV derived with Planck data. Successful models are those using prolate astrosilicate grains with an elongation a/b=3 and an inclusion of 20% porosity. The spectral dependence of the polarized SED is steeper in our models than in the data. Models perform slightly better when a-C grains are aligned. A small (6%) volume inclusion of a-C in the astrosilicate matrix removes the need for porosity and perfect grain alignment, and improves the fit to the polarized SED.
Conclusions. Dust models based on astrosilicates can be reconciled with data by adapting the shape of grains and adding inclusions of porosity or a-C in the astrosilicate matrix.

Abstract Copyright: © ESO, 2018

Journal keyword(s): polarization - dust - extinction - submillimeter: ISM - methods: numerical

Simbad objects: 4

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Number of rows : 4

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 M 31 G 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 10946 1
2 M 41 OpC 06 46 01 -20 45.4   4.89 4.5     ~ 248 0
3 NAME Vela C Cld 08 57 -43.2           ~ 124 0
4 NGC 6618 OpC 18 20 47 -16 10.3           ~ 1485 0

    Equat.    Gal    SGal    Ecl

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2020.08.04-22:53:25

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