Adaptable radiative transfer innovations for submillimetre telescopes (ARTIST)

Dust polarisation module (DustPol)

¹ Institut de Ciències de l’Espai (CSIC–IEEC), Campus UAB, Facultat de Ciències, Torre C5p, 08193 Bellaterra, Catalunya, Spain
e-mail: padovani@ice.cat; girart@ice.cat; frau@ice.cat
² Centre for Star and Planet Formation and Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen Ø., Denmark
e-mail: brinch@nbi.dk; jeskj@nbi.dk
³ Laboratoire de radioastronomie, UMR 8112 du CNRS, École normale supérieure et Observatoire de Paris, 24 rue Lhomond, 75231 Paris Cedex 05, France
e-mail: patrick.hennebelle@lra.ens.fr
⁴ Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
e-mail: rolf.kuiper@jpl.nasa.gov
⁵ Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, 439 92 Onsala, Sweden
e-mail: wouter.vlemmings@chalmers.se
⁶ Argenlander Institute for Astronomy, University of Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
e-mail: bertoldi@astro.uni-bonn.de; bertoldi@astro.uni-bonn.de
⁷ Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
e-mail: michiel@strw.leidenuniv.nl; juhasz@strw.leidenuniv.nl

Received: 13 February 2012
Accepted: 28 April 2012

Abstract

We present a new publicly available tool (DustPol) aimed to model the polarised thermal dust emission. The module DustPol, which is publicly available, is part of the ARTIST (Adaptable Radiative Transfer Innovations for Submillimetre Telescopes) package, which also offers tools for modelling the polarisation of line emission together with a model library and a Python-based user interface. DustPol can easily manage analytical as well as pre-gridded models to generate synthetic maps of the Stokes I, Q, and U parameters. These maps are stored in FITS format which is straightforwardly read by the data reduction software used, e.g., by the Atacama Large Millimeter Array (ALMA). This turns DustPol into a powerful engine for the prediction of the expected polarisation features of a source observed with ALMA or the Planck satellite as well as for the interpretation of existing submillimetre observations obtained with other telescopes. DustPol allows the parameterisation of the maximum degree of polarisation and we find that, in a prestellar core, if there is depolarisation, this effect should happen at densities of 10⁶ cm^-3 or larger. We compare a model generated by DustPol with the observational polarisation data of the low-mass Class 0 object NGC 1333 IRAS 4A, finding that the total and the polarised emission are consistent.