The dust content of the Crab Nebula
Date Issued
2019
Author(s)
De Looze, I.
•
Barlow, M. J.
•
•
Bevan, A.
•
Bietenholz, M. F.
•
Chawner, H.
•
Gomez, H. L.
•
Matsuura, M.
•
Priestley, F.
•
Wesson, R.
Description
The authors would like to thank Rick Arendt for kindly sharing his mm data (GISMO 2 mm and MUSTANG 3.3 mm) of the Crab Nebula; and Isabella Lamperti, Anthony Jones, Bruce Draine and Boris Leistedt for fruitful discussions. IDL gratefully acknowledges the support of the Research Foundation Flanders (FWO). MJB, AB, and RW acknowledge support from European Research Council (ERC) Ad- vanced Grant SNDUST 694520. MM acknowledges support from STFC Ernest Rutherford fellowship (ST/L003597/1). HLG and HC acknowledges support from the European Research Council (ERC) in the form of Consolidator Grant COSMICDUST. FP acknowledges support from the UK Science and Technology Funding Council (STFC). PACS was developed by a consortium of institutes led by MPE (Germany) and including UVIE (Austria); KU Leuven, CSL, IMEC (Belgium); CEA, LAM (France); MPIA (Germany); INAFIFSI/ OAA/OAP/OAT, LENS, SISSA (Italy); IAC (Spain). This development has been sup- ported by the funding agen- cies BMVIT (Austria), ESA- PRODEX (Belgium), CEA/CNES (France), DLR (Ger- many), ASI/INAF (Italy), and CICYT/ MCYT (Spain). SPIRE was developed by a consortium of institutes led by Cardiff University (UK) and including Univ. Lethbridge (Canada); NAOC (China); CEA, LAM (France); IFSI, Univ. Padua (Italy); IAC (Spain); Stockholm Observatory (Sweden); Imperial College London, RAL, UCL-MSSL, UKATC, Univ. Sussex (UK); and Caltech, JPL, NHSC, Univ. Colorado (USA). This development has been supported by national funding agencies: CSA (Canada); NAOC (China); CEA, CNES, CNRS (France); ASI (Italy); MCINN (Spain); SNSB (Sweden); STFC and UKSA (UK); and NASA (USA).
Abstract
We have modelled the near-infrared to radio images of the Crab Nebula with a Bayesian SED model to simultaneously fit its synchrotron, interstellar (IS), and supernova dust emission. We infer an IS dust extinction map with an average AV = 1.08 ± 0.38 mag, consistent with a small contribution ({≲ }22{{ per cent}}) to the Crab's overall infrared emission. The Crab's supernova dust mass is estimated to be between 0.032 and 0.049 M☉ (for amorphous carbon grains) with an average dust temperature Tdust = 41 ± 3 K, corresponding to a dust condensation efficiency of 8-12 {{ per cent}}. This revised dust mass is up to an order of magnitude lower than some previous estimates, which can be attributed to our different IS dust corrections, lower SPIRE flux densities, and higher dust temperatures than were used in previous studies. The dust within the Crab is predominantly found in dense filaments south of the pulsar, with an average V-band dust extinction of AV = 0.20-0.39 mag, consistent with recent optical dust extinction studies. The modelled synchrotron power-law spectrum is consistent with a radio spectral index αradio = 0.297 ± 0.009 and an infrared spectral index αIR = 0.429 ± 0.021. We have identified a millimetre excess emission in the Crab's central regions, and argue that it most likely results from two distinct populations of synchrotron emitting particles. We conclude that the Crab's efficient dust condensation (8-12 {{ per cent}}) provides further evidence for a scenario where supernovae can provide substantial contributions to the IS dust budgets in galaxies.
Volume
488
Issue
1
Start page
164
Issn Identifier
0035-8711
Ads BibCode
2019MNRAS.488..164D
Rights
open.access
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