2018A&A...614A..65M


C.D.S. - SIMBAD4 rel 1.7 - 2020.10.28CET06:53:17

2018A&A...614A..65M - Astronomy and Astrophysics, volume 614A, 65-65 (2018/6-1)

VISION - Vienna Survey in Orion. II. Infrared extinction in Orion A.

MEINGAST S., ALVES J. and LOMBARDI M.

Abstract (from CDS):

We have investigated the shape of the extinction curve in the infrared up to ∼25µm for the Orion A star-forming complex. The basis of this work is near-infrared data acquired with the Visual and Infrared Survey Telescope for Astronomy, in combination with Pan-STARRS and mid-infrared Spitzer photometry. We obtain colour excess ratios for eight passbands by fitting a series of colour-colour diagrams. The fits are performed using Markov chain Monte Carlo methods, together with a linear model under a Bayesian formalism. The resulting colour excess ratios are directly interpreted as a measure of the extinction law. We show that the Orion A molecular cloud is characterized by flat mid-infrared extinction, similar to many other recently studied sightlines. Moreover, we find statistically significant evidence that the extinction law from ∼1µm to at least ∼6µm varies across the cloud. In particular, we find a gradient along galactic longitude, where regions near the Orion Nebula Cluster show a different extinction law compared to L1641 and L1647, the low-mass star-forming sites in the cloud complex. These variations are of the order of only 3% and are most likely caused by the influence of the massive stars on their surrounding medium. While the observed general trends in our measurements are in agreement with model predictions, both well-established and new dust grain models are not able to fully reproduce our infrared extinction curve. We also present a new extinction map featuring a resolution of 1' and revisit the correlation between extinction and dust optical depth. This analysis shows that cloud substructure, which is not sampled by background sources, affects the conversion factor between these two measures. In conclusion, we argue that specific characteristics of the infrared extinction law are still not well understood, but Orion A can serve as an unbiased template for future studies.

Abstract Copyright: © ESO 2018

Journal keyword(s): ISM: clouds - ISM: structure - dust, extinction - methods: data analysis - methods: statistical

VizieR on-line data: <Available at CDS (J/A+A/614/A65): list.dat fits/*>

Simbad objects: 16

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Number of rows : 16

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 NAME Perseus Cloud SFR 03 35.0 +31 13           ~ 1086 0
2 NAME Orion Nebula Cluster OpC 05 35.0 -05 29           ~ 2014 1
3 NAME OMC-1 MoC 05 35 14 -05 22.4           ~ 1025 2
4 NGC 1980 OpC 05 35 24 -05 54.9     2.5     ~ 87 0
5 NAME Ori A MoC 05 38 -07.1           ~ 2698 0
6 NAME LDN 1641 Center DNe 05 38 46.4 -07 01 05           ~ 51 0
7 LDN 1641 MoC 05 39.0 -07 00           ~ 428 0
8 NAME Ori B MoC 05 41 43.0 -01 54 44           ~ 1182 0
9 LDN 1647 DNe 05 42.4 -09 58           ~ 24 1
10 M 78 RNe 05 46 45.8 +00 04 45   8.0       ~ 345 0
11 NAME Coalsack Nebula DNe 12 31 19 -63 44.6           ~ 242 0
12 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3066 0
13 LDN 1746 DNe 17 11.3 -27 22           ~ 109 0
14 NAME the Pipe Nebula DNe 17 30 -25.0           ~ 339 1
15 DCld 001.6+03.8 DNe 17 35 47.50 -25 32 59.0           ~ 53 0
16 NAME Serpens Cloud SFR 18 29 49 +01 14.8           ~ 927 2

    Equat.    Gal    SGal    Ecl

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2020.10.28-06:53:17

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