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Published June 1, 2016 | Submitted + Supplemental Material + Published
Journal Article Open

The bandmerged Planck Early Release Compact Source Catalogue: probing sub-structure in the molecular gas at high Galactic latitude


The Planck Early Release Compact Source Catalogue (ERCSC) includes nine lists of highly reliable sources, individually extracted at each of the nine Planck frequency channels. To facilitate the study of the Planck sources, especially their spectral behaviour across the radio/infrared frequencies, we provide a 'bandmerged' catalogue of the ERCSC sources. This catalogue consists of 15 191 entries, with 79 sources detected in all nine frequency channels of Planck and 6818 sources detected in only one channel. We describe the bandmerging algorithm, including the various steps used to disentangle sources in confused regions. The multifrequency matching allows us to develop spectral energy distributions of sources between 30 and 857 GHz, in particular across the 100 GHz band, where the energetically important CO J = 1→0 line enters the Planck bandpass. We find ∼3σ–5σ evidence for contribution to the 100 GHz intensity from foreground CO along the line of sight to 147 sources with |b|>30∘. The median excess contribution is 4.5 ± 0.9 per cent of their measured 100 GHz flux density which cannot be explained by calibration or beam uncertainties. This translates to 0.5 ± 0.1 K km s^(−1) of CO which must be clumped on the scale of the Planck 100 GHz beam, i.e. ∼10 arcmin. If this is due to a population of low-mass (∼15 M_⊙) molecular gas clumps, the total mass in these clumps may be more than 2000 M_⊙. Further, high-spatial-resolution, ground-based observations of the high-latitude sky will help shed light on the origin of this diffuse, clumpy CO emission.

Additional Information

© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2016 February 25. Received 2016 February 25. In original form 2014 August 28. First published online March 2, 2016. We thank the referee for thoughtful comments which improved the manuscript. We also thank Dr Clive Dickinson for helpful discussions in the preparation of this paper. This research has made use of the NASA/IPAC Extragalactic Database (NED) and NASA/IPAC Infrared Science Archive, which are operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. Some of the results in this paper have been derived using the HEALPIX (Górski et al. 2005) package.

Attached Files

Published - MNRAS-2016-Chen-3619-32.pdf

Submitted - 1602.07785v1.pdf

Supplemental Material - Table4_full.zip


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