From flux to dust mass: Does the grain-temperature distribution matter for estimates of cold dust masses in supernova remnants?
Number of Authors: 4
2015 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 449, no 4, 4079-4090 p.Article in journal (Refereed) Published
The amount of dust estimated from infrared to sub-millimetre (submm) observations strongly depends on assumptions of different grain sizes, compositions and optical properties. Here we use a simple model of thermal emission from cold silicate/carbon dust at a range of dust grain temperatures and fit the spectral energy distribution (SED) of the Crab nebula as a test. This can lower the derived dust mass for the Crab by similar to 50 per cent and 30-40 per cent for astronomical silicates and amorphous carbon grains compared to recently published values (0.25 M-circle dot -> 0.12 M-circle dot and 0.12 M-circle dot -> 0.072 M-circle dot, respectively), but the implied dustmass can also increase by as much as almost a factor of 6 (0.25 M-circle dot -> 1.14 M-circle dot and 0.12 M-circle dot -> 0.71 M-circle dot) depending on assumptions regarding the sizes/temperatures of the coldest grains. The latter values are clearly unrealistic due to the expected metal budget, though. Furthermore, we show by a simple numerical experiment that if a cold-dust component does have a grain-temperature distribution, it is almost unavoidable that a two-temperature fit will yield an incorrect dust mass estimate. But we conclude that grain temperatures is not a greater uncertainty than the often poorly constrained emissivities (i.e. material properties) of cosmic dust, although there is clearly a need for improved dust emission models. The greatest complication associated with deriving dust masses still arises in the uncertainty in the dust composition.
Place, publisher, year, edition, pages
2015. Vol. 449, no 4, 4079-4090 p.
Stars: AGB and post-AGB, supernovae: general, supernovae: individual: Crab nebula, dust, extinction
IdentifiersURN: urn:nbn:se:su:diva-119057DOI: 10.1093/mnras/stv487ISI: 000355342000056OAI: oai:DiVA.org:su-119057DiVA: diva2:846400