Universität zu Köln

Ibanez-Mejia, Juan C., Walch, Stefanie, Ivlev, Alexei V., Clarke, Seamus ORCID: 0000-0001-9751-4603, Caselli, Paola and Joshi, Prabesh R. (2019). Dust charge distribution in the interstellar medium. Mon. Not. Roy. Astron. Soc., 485 (1). S. 1220 - 1248. OXFORD: OXFORD UNIV PRESS. ISSN 1365-2966

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Abstract

We investigate the equilibrium charge distribution of dust grains in the interstellar medium (ISM). Our treatment accounts for collisional charging by electrons and ions, photoelectric charging due to a background interstellar radiation field, the collection of suprathermal cosmic ray electrons and photoelectric emission due to a cosmic ray induced ultraviolet radiation field within dense molecular clouds. We find that the charge equilibrium assumption is valid throughout the multiphase ISM conditions investigated here, and should remain valid for simulations with resolutions down to au scales. The charge distribution of dust grains is size, composition, and ISM environment dependent: local radiation field strength, G, temperature, T, and electron number density, n(e). The charge distribution is tightly correlated with the 'charging parameter', G root T/n(e). In the molecular medium, both carbonaceous and silicate grains have pre-dominantly negative or neutral charges with narrow distributions. In the cold neutral medium, carbonaceous and silicate grains vary from negative and narrow distributions, to pre-dominantly positive and wide distributions depending on the magnitude of the charging parameter. In the warm neutral medium, grains of all sizes are positively charged with wide distributions. We derive revised parametric expressions that can be used to recover the charge distribution function of carbonaceous and silicate grains from 3.5 angstrom to 0.25 mu m as a function of the size, composition, and ambient ISM parameters. Finally, we find that the parametric equations can be used in environments other than Solar neighbourhood conditions, recovering the charge distribution function of dust grains in photon dominated regions.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Ibanez-Mejia, Juan C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Walch, Stefanie UNSPECIFIED UNSPECIFIED UNSPECIFIED Ivlev, Alexei V. UNSPECIFIED UNSPECIFIED UNSPECIFIED Clarke, Seamus UNSPECIFIED orcid.org/0000-0001-9751-4603 UNSPECIFIED Caselli, Paola UNSPECIFIED UNSPECIFIED UNSPECIFIED Joshi, Prabesh R. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-149806
DOI:	10.1093/mnras/stz207
Journal or Publication Title:	Mon. Not. Roy. Astron. Soc.
Volume:	485
Number:	1
Page Range:	S. 1220 - 1248
Date:	2019
Publisher:	OXFORD UNIV PRESS
Place of Publication:	OXFORD
ISSN:	1365-2966
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language MAGNETOHYDRODYNAMIC SHOCK-WAVES; MOLECULAR CLOUD EVOLUTION; ADAPTIVE MESH REFINEMENT; GRAIN-GRAIN COLLISIONS; DENSE CLOUDS; PHOTOELECTRIC-EMISSION; RADIATION-FIELD; STAR-FORMATION; DESTRUCTION; IONIZATION Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/14980