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A PPMAP analysis of the filamentary structures in Ophiuchus L1688 and L1689

Howard, A. D. P. and Whitworth, A. P. and Griffin, M. J. and Marsh, K. A. and Smith, M. W. L. (2021) A PPMAP analysis of the filamentary structures in Ophiuchus L1688 and L1689. Monthly Notices of the Royal Astronomical Society, 504 (4). pp. 6157-6178. ISSN 0035-8711. doi:10.1093/mnras/stab1166.

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We use the Point Process MAPping (PPMAP) algorithm to reanalyse the Herschel and SCUBA-2 observations of the L1688 and L1689 subregions of the Ophiuchus molecular cloud. PPMAP delivers maps with high resolution (here 14 arcsec, corresponding to ∼0.01pc at ∼140pc), by using the observations at their native resolutions. PPMAP also delivers more accurate dust optical depths, by distinguishing dust of different types and at different temperatures. The filaments and pre-stellar cores almost all lie in regions with N_(H₂) ≳ 7×10²¹ cm⁻² (corresponding to A_V ≳ 7). The dust temperature, T, tends to be correlated with the dust opacity index, β, with low T and low β concentrated in the interiors of filaments. The one exception to this tendency is a section of filament in L1688 that falls – in projection – between the two B stars: S1 and HD147889; here T and β are relatively high, and there is compelling evidence that feedback from these two stars has heated and compressed the filament. Filament FWHMS are typically in the range 0.10 to 0.15pc. Most filaments have line-densities in the range 25 to 65M⊙pc⁻¹⁠. If their only support is thermal gas pressure, and the gas is at the canonical temperature of 10K⁠, the filaments are highly supercritical. However, there is some evidence from ammonia observations that the gas is significantly warmer than this, and we cannot rule out the possibility of additional support from turbulence and/or magnetic fields. On the basis of their spatial distribution, we argue that most of the starless cores are likely to disperse (rather than evolving to become pre-stellar).

Item Type:Article
Related URLs:
URLURL TypeDescription Paper ItemHerschel Science Archive Gould Belt Survey catalogue
Howard, A. D. P.0000-0002-3900-1313
Whitworth, A. P.0000-0002-1178-5486
Griffin, M. J.0000-0002-0033-177X
Marsh, K. A.0000-0003-0107-7803
Smith, M. W. L.0000-0002-3532-6970
Additional Information:© 2021 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. Accepted 2021 March 31. Received 2021 March 29; in original form 2020 October 26. Published: 30 April 2021. We thank the referee, Doris Arzoumanian, for her very thorough and thoughtful report, which helped us to improve the original version of this paper. This research made use of PHOTUTILS, an ASTROPY package for detection and photometry of astronomical sources (Bradley et al. 2016). ADPH gratefully acknowledges the support of a PhD studentship from the UK Science and Technology Facilities Council (STFC). APW, MJG, and MWLS gratefully acknowledge the support of a Consolidated Grant (ST/K00926/1) from the STFC. Data Availability: The observational data underpinning this article are collected from the Herschel Space Observatory and the James Clerk Maxwell Telescope (JCMT), and are publicly available from Herschel Science Archive ( and the JCMT Gould Belt Survey (, respectively. The core catalogue presented in Ladjelate et al. (2020) is publicly available from The derived data generated in this research will be shared on request to the corresponding author.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Science and Technology Facilities Council (STFC)ST/K00926/1
Subject Keywords:stars: formation – dust, extinction – ISM: structure – submillimetre: ISM
Issue or Number:4
Record Number:CaltechAUTHORS:20210715-194857549
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Official Citation:A D P Howard, A P Whitworth, M J Griffin, K A Marsh, M W L Smith, A PPMAP analysis of the filamentary structures in Ophiuchus L1688 and L1689, Monthly Notices of the Royal Astronomical Society, Volume 504, Issue 4, July 2021, Pages 6157–6178,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:109852
Deposited By: Tony Diaz
Deposited On:15 Jul 2021 20:33
Last Modified:15 Jul 2021 20:33

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