Bibcode
Planck Collaboration; Abergel, A.; Ade, P. A. R.; Aghanim, N.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Balbi, A.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Battaner, E.; Benabed, K.; Benoît, A.; Bernard, J.-P.; Bersanelli, M.; Bhatia, R.; Blagrave, K.; Bock, J. J.; Bonaldi, A.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Boulanger, F.; Bucher, M.; Burigana, C.; Cabella, P.; Cantalupo, C. M.; Cardoso, J.-F.; Catalano, A.; Cayón, L.; Challinor, A.; Chamballu, A.; Chiang, L.-Y.; Chiang, C.; Christensen, P. R.; Clements, D. L.; Colombi, S.; Couchot, F.; Coulais, A.; Crill, B. P.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Gasperis, G.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Dickinson, C.; Donzelli, S.; Doré, O.; Dörl, U.; Douspis, M.; Dupac, X.; Efstathiou, G.; Enßlin, T. A.; Eriksen, H. K.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Galeotta, S.; Ganga, K.; Giard, M.; Giardino, G.; Giraud-Héraud, Y.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Hansen, F. K.; Harrison, D.; Helou, G.; Henrot-Versillé, S.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hovest, W.; Hoyland, R. J.; Huffenberger, K. M.; Jaffe, A. H.; Joncas, G.; Jones, A.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knox, L.; Kurki-Suonio, H.; Lagache, G. et al.
Bibliographical reference
Astronomy and Astrophysics, Volume 536, id.A24
Advertised on:
12
2011
Journal
Citations
191
Refereed citations
180
Description
This paper presents the first results from a comparison of Planck dust
maps at 353, 545 and 857GHz, along with IRAS data at 3000 (100 μm)
and 5000GHz (60 μm), with Green Bank Telescope 21-cm observations of
Hi in 14 fields covering more than 800 deg2 at high Galactic
latitude. The main goal of this study is to estimate the far-infrared to
sub-millimeter (submm) emissivity of dust in the diffuse local
interstellar medium (ISM) and in the intermediate-velocity (IVC) and
high-velocity clouds (HVC) of the Galactic halo. Galactic dust emission
for fields with average Hi column density lower than 2 ×
1020 cm-2 is well correlated with 21-cm emission
because in such diffuse areas the hydrogen is predominantly in the
neutral atomic phase. The residual emission in these fields, once the
Hi-correlated emission is removed, is consistent with the expected
statistical properties of the cosmic infrared background fluctuations.
The brighter fields in our sample, with an average Hi column density
greater than 2 × 1020 cm-2, show significant
excess dust emission compared to the Hi column density. Regions of
excess lie in organized structures that suggest the presence of hydrogen
in molecular form, though they are not always correlated with CO
emission. In the higher Hi column density fields the excess emission at
857 GHz is about 40% of that coming from the Hi, but over all the high
latitude fields surveyed the molecular mass faction is about 10%. Dust
emission from IVCs is detected with high significance by this
correlation analysis. Its spectral properties are consistent with,
compared to the local ISM values, significantly hotter dust (T ~ 20K),
lower submm dust opacity normalized per H-atom, and a relative abundance
of very small grains to large grains about four times higher. These
results are compatible with expectations for clouds that are part of the
Galactic fountain in which there is dust shattering and fragmentation.
Correlated dust emission in HVCs is not detected; the average of the
99.9% confidence upper limits to the emissivity is 0.15 times the local
ISM value at 857 and 3000GHz, in accordance with gas phase evidence for
lower metallicity and depletion in these clouds. Unexpected
anti-correlated variations of the dust temperature and emission
cross-section per H atom are identified in the local ISM and IVCs, a
trend that continues into molecular environments. This suggests that
dust growth through aggregation, seen in molecular clouds, is active
much earlier in the cloud condensation and star formation processes.
Corresponding author: M.-A. Miville-Deschênes, e-mail:
mamd [at] ias.u-psud.fr (mamd[at]ias[dot]u-psud[dot]fr)
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