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The pros and cons of the inversion method approach to derive 3D dust emission properties in the ISM: the Hi-GAL field centred on (l, b) = (30°, 0°)

Traficante, A. and Paladini, R. and Compiegne, M. and Alves, M. I. R. and Cambrésy, L. and Gibson, S. J. and Tibbs, C. T. and Noriega-Crespo, A. and Molinari, S. and Carey, S. J. and Ingalls, J. G. and Natoli, P. and Davies, R. D. and Davis, R. J. and Dickinson, C. and Fuller, G. A. (2014) The pros and cons of the inversion method approach to derive 3D dust emission properties in the ISM: the Hi-GAL field centred on (l, b) = (30°, 0°). Monthly Notices of the Royal Astronomical Society, 440 (4). pp. 3588-3612. ISSN 0035-8711. https://resolver.caltech.edu/CaltechAUTHORS:20140620-102116115

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Abstract

Herschel far-infrared continuum data obtained as part of the Hi-GAL survey have been used, together with the GLIMPSE 8 μm and MIPSGAL 24 μm data, to attempt the first 3D-decomposition of dust emission associated with atomic, molecular and ionized gas at 15 arcmin angular resolution. Our initial test case is a 2 × 2 square degrees region centred on (l, b) = (30°, 0°), a direction that encompasses the origin point of the Scutum–Crux Arm at the tip of the Galactic Bar. Coupling the IR maps with velocity maps specific for different gas phases (H i 21cm, ^(12)CO and ^(13)CO, and radio recombination lines), we estimate the properties of dust blended with each of the gas components and at different Galactocentric distances along the line of sight (LOS). A statistical Pearson's coefficients analysis is used to study the correlation between the column densities estimated for each gas component and the intensity of the IR emission. This analysis provides evidence that the 2 × 2 square degree field under consideration is characterized by the presence of a gas component not accounted for by the standard tracers, possibly associated with warm H_2 and cold H I. We demonstrate that the IR radiation in the range 8 < λ < 500 μm is systematically dominated by emission originating within the Scutum–Crux Arm. By applying an inversion method, we recover the dust emissivities associated with atomic, molecular and ionized gas. Using the DustEM model, we fit the spectral energy distributions for each gas phase, and find average dust temperatures of T_(d,H I) = 18.82 ± 0.47 K, T_(d,H_2) = 18.84 ± 1.06 K and T_(d,H II) = 22.56 ± 0.64 K, respectively. We also obtain an indication for polycyclic aromatic hydrocarbons depletion in the diffuse ionized gas. We demonstrate the importance of including the ionized component in 3D-decompositions of the total IR emission. However, the main goal of this work is to discuss the impact of the missing column density associated with the dark gas component on the accurate evaluation of the dust properties, and to shed light on the limitations of the inversion method approach when this is applied to a small section of the Galactic plane and when the working resolution allows sufficient de-blending of the gas components along the LOS.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1093/mnras/stu493DOIArticle
http://arxiv.org/abs/1403.3327arXivDiscussion Paper
ORCID:
AuthorORCID
Paladini, R.0000-0002-5158-243X
Noriega-Crespo, A.0000-0002-6296-8960
Carey, S. J.0000-0002-0221-6871
Ingalls, J. G.0000-0003-4714-1364
Dickinson, C.0000-0002-0045-442X
Fuller, G. A.0000-0001-8509-1818
Additional Information:© 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2014 March 12. Received 2014 February 14; in original form 2012 June 22. The authors want to thank Mark Calabretta and Lister Staveley-Smith for their work on the RRL data. AT is supported by an STFC grant to JBCA. CD acknowledges an STFC Advanced Fellowship and an EU Marie-Curie grant under the FP7. MIRA acknowledges the support by the European Research Council grant MISTIC (ERC-267934). Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.
Funders:
Funding AgencyGrant Number
Science and Technology Facilities Council (STFC)UNSPECIFIED
Marie Curie FellowshipUNSPECIFIED
European Research Council (ERC)267934
Subject Keywords: dust, extinction Galaxy: structure infrared: ISM
Issue or Number:4
Record Number:CaltechAUTHORS:20140620-102116115
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20140620-102116115
Official Citation:A. Traficante, R. Paladini, M. Compiegne, M. I. R. Alves, L. Cambrésy, S. J. Gibson, C. T. Tibbs, A. Noriega-Crespo, S. Molinari, S. J. Carey, J. G. Ingalls, P. Natoli, R. D. Davies, R. J. Davis, C. Dickinson, and G. A. Fuller The pros and cons of the inversion method approach to derive 3D dust emission properties in the ISM: the Hi-GAL field centred on (l, b) = (30°, 0°) MNRAS (June 1, 2014) Vol. 440 3588-3612 doi:10.1093/mnras/stu493
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:46396
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:20 Jun 2014 18:02
Last Modified:14 Nov 2019 23:49

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