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L1495 revisited: a ppmap view of a star-forming filament

Howard, A. D. P. and Whitworth, A. P. and Marsh, K. A. and Clarke, S. D. and Griffin, M. J. and Smith, M. W. L. and Lomax, O. D. (2019) L1495 revisited: a ppmap view of a star-forming filament. Monthly Notices of the Royal Astronomical Society, 489 (1). pp. 962-976. ISSN 0035-8711. doi:10.1093/mnras/stz2234.

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We have analysed the Herschel and SCUBA-2 dust continuum observations of the main filament in the Taurus L1495 star-forming region, using the Bayesian fitting procedure PPMAP. (i) If we construct an average profile along the whole length of the filament, it has FWHM ≃0.087±0.003pc; but the closeness to previous estimates is coincidental. (ii) If we analyse small local sections of the filament, the column-density profile approximates well to the form predicted for hydrostatic equilibrium of an isothermal cylinder. (iii) The ability of PPMAP to distinguish dust emitting at different temperatures, and thereby to discriminate between the warm outer layers of the filament and the cold inner layers near the spine, leads to a significant reduction in the surface-density, Σ⁠, and hence in the line-density, μ. If we adopt the canonical value for the critical line-density at a gas-kinetic temperature of 10K⁠, μ_(CRIT) ≃ 16M⊙pc⁻¹⁠, the filament is on average trans-critical, with μ∼μ_(CRIT); local sections where μ > μ_(CRIT) tend to lie close to prestellar cores. (iv) The ability of PPMAP to distinguish different types of dust, i.e. dust characterized by different values of the emissivity index, β, reveals that the dust in the filament has a lower emissivity index, β ≲ 1.5, than the dust outside the filament, β ≳ 1.7, implying that the physical conditions in the filament have effected a change in the properties of the dust.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Howard, A. D. P.0000-0002-3900-1313
Marsh, K. A.0000-0003-0107-7803
Clarke, S. D.0000-0001-9751-4603
Smith, M. W. L.0000-0002-3532-6970
Additional Information:© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model ( Accepted 2019 July 30. Received 2019 July 30; in original form 2019 June 20. Published: 12 August 2019. ADPH gratefully acknowledges the support of a postgraduate scholarship from the School of Physics & Astronomy at Cardiff University and the UK Science and Technology Facilities Council. APW, MJG and ODL gratefully acknowledge the support of a consolidated grant (ST/K00926/1) from the UK Science and Technology Funding Council. ODL is also grateful for the support of an ESA fellowship. SDC gratefully acknowledges support from the ERC starting grant no. 679852 ‘RADFEEDBACK’. We thank Sümeyye Suri for her help in extracting continuous structures from the DISPERSE algorithm, Emily Drabek-Maunder for providing the SCUBA-2 observations, and Philippe André for providing very helpful feedback on an earlier version. We also thank the referee for their encouraging report. The computations have been performed on the Cardiff University Advanced Research Computing facility, ARCCA.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Cardiff UniversityUNSPECIFIED
Science and Technology Facilities Council (STFC)ST/K00926/1
European Space Agency (ESA)UNSPECIFIED
European Research Council (ERC)679852
Subject Keywords:stars: formation – dust, extinction – ISM: structure – submillimetre: ISM
Issue or Number:1
Record Number:CaltechAUTHORS:20191025-125142264
Persistent URL:
Official Citation:A D P Howard, A P Whitworth, K A Marsh, S D Clarke, M J Griffin, M W L Smith, O D Lomax, L1495 revisited: a PPMAP view of a star-forming filament, Monthly Notices of the Royal Astronomical Society, Volume 489, Issue 1, October 2019, Pages 962–976,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:99455
Deposited By: Tony Diaz
Deposited On:25 Oct 2019 19:59
Last Modified:16 Nov 2021 17:46

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