The initial conditions of isolated star formation – VII. Spitzer mapping of pre-stellar cores |
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Authors: | J M Kirk D Ward-Thompson P André |
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Institution: | School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff CF24 3AA;Observatoire de Bordeaux, 2 rue de l'Observatoire, 33270 Floirac, France;CEA, DSM, DAPNIA, Service d'Astrophysique, CE Saclay, F-91191 Gif-sur-Yvette Cedex, France |
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Abstract: | We have retrieved Spitzer archive data of pre-stellar cores taken with the Multiband Imaging Photometer for Spitzer (MIPS) at a wavelength of 160 μm. Seventeen images, containing 18 cores, were constructed. Flux densities were measured for each core, and background estimates were made. Mean off-source backgrounds were found to be 48 ± 10 MJy sr?1 in Taurus and 140 ± 55 MJy sr?1 in Ophiuchus. Consistency was found between the MIPS 170-μm and ISOPHOT 160-μm calibrations. Fourteen cores were detected both by MIPS and by our previous submillimetre surveys. Spectral energy distributions were made for each core, using additional 24- and 70-μm data from the Spitzer data archive, as well as previous infrared and submillimetre data. Previous temperature estimates were refined, and new temperature estimates were made where no Infrared Space Observatory ( ISO ) data exist. A temperature range of 8–18 K was found for the cores, with most lying in the range 10–13 K. We discount recent claims that a large number of pre-stellar cores may have been misclassified and in fact contain low-luminosity protostars detectable only by Spitzer . We find no new protostars in our sample other than that previously reported in L1521F. It is shown that this has a negligible effect on pre-stellar lifetime estimates. |
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Keywords: | stars: formation dust extinction infrared: ISM |
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