Publications (3)0 Total impact
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M. Juvela,
I. Ristorcelli,
L. Pagani,
Y. Doi,
V. -M. Pelkonen,
D. J. Marshall,
J. -P. Bernard,
E. Falgarone,
J. Malinen,
G. Marton,
P. McGehee,
L. A. Montier,
F. Motte,
R. Paladini,
L. V. Toth,
N. Ysard, S. Zahorecz,
A. Zavagno
[show abstract]
[hide abstract]
ABSTRACT: We examine the cloud structure around the Planck detections in 71 fields
observed with the Herschel SPIRE instrument. We wish to determine the general
physical characteristics of the fields and to examine the morphology of the
clouds where the cold high column density clumps are found. We derive colour
temperature and column density maps of the fields. We examine the infrared
spectral energy distributions of the main clumps. The clouds are categorised
according to their large scale morphology. With the help of recently released
WISE satellite data, we look for signs of enhanced mid-infrared scattering
(coreshine), an indication of growth of the dust grains, and examine the star
formation activity associated with the cold clumps. The mapped clouds have
distances ranging from ~100pc to several kiloparsecs and cover a range of sizes
and masses from cores of less than 10 solar masses to clouds with masses in
excess of 10000 solar mass. Most fields contain some filamentary structures and
in about half of the cases a filament or a few filaments dominate the
morphology. In one case out of ten, the clouds show a cometary shape or have
sharp boundaries indicative of compression by an external force. The width of
the filaments is typically ~0.2-0.3pc. However, there is significant variation
from 0.1pc to 1pc and the estimates are sensitive to the methods used and the
very definition of a filament. Enhanced mid-infrared scattering, coreshine, was
detected in four clouds with six additional tentative detections. The cloud
LDN183 is included in our sample and remains the best example of this
phenomenon. About half of the fields are associated with active star formation
as indicated by the presence of mid-infrared point sources. The mid-infrared
sources often coincide with structures whose sub-millimetre spectra are still
dominated by the cold dust.
02/2012;
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P. A. R. Ade,,
N. Aghanim,,
M. Arnaud,,
M. Ashdown,,
J. Aumont,,
C. Baccigalupi,,
A. Balbi,,
A. J. Banday,,
R. B. Barreiro,,
J. G. Bartlett,, [......],
P. Vielva,,
F. Villa,,
N. Vittorio,,
L. A. Wade,,
B. D. Wandelt,,
N. Ysard,,
D. Yvon,,
A. Zacchei,, S. Zahorecz,
A. Zonca
[show abstract]
[hide abstract]
ABSTRACT: We present the statistical properties of the Cold Clump Catalogue of Planck Objects (C3PO), the first all-sky catalogue of cold objects, in terms of their spatial distribution, dust temperature, distance, mass, and morphology. We have combined Planck and IRAS data to extract 10342 cold sources that stand out against a warmer environment. The sources are distributed over the whole sky, including in the Galactic plane, despite the confusion, and up to high latitudes (>30°). We find a strong spatial correlation of these sources with ancillary data tracing Galactic molecular structures and infrared dark clouds where the latter have been catalogued. These cold clumps are not isolated but clustered in groups. Dust temperature and emissivity spectral index values are derived from their spectral energy distributions using both Planck and IRAS data. The temperatures range from 7K to 19K, with a distribution peaking around 13K. The data are inconsistent with a constant value of the associated spectral index β over the whole temperature range: β varies from 1.4 to 2.8, with a mean value around 2.1. Distances are obtained for approximately one third of the objects. Most of the detections lie within 2kpc of the Sun, but more distant sources are also detected, out to 7kpc. The mass estimates inferred from dust emission range from 0.4 M⊙ to 2.4 × 105 M⊙. Their physical properties show that these cold sources trace a broad range of objects, from low-mass dense cores to giant molecular clouds, hence the “cold clump” terminology. This first statistical analysis of the C3PO reveals at least two colder populations of special interest with temperatures in the range 7 to 12K: cores that mostly lie close to the Sun; and massive cold clumps located in the inner Galaxy. We also describe the statistics of the early cold core (ECC) sample that is a subset of the C3PO, containing only the 915 most reliable detections. The ECC is delivered as a part of the Planck Early Release Compact Source Catalogue (ERCSC).
åp. 12/2011; 536:A23.
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Planck Collaboration,
P. A. R. Ade,
N. Aghanim,
M. Arnaud,
M. Ashdown,
J. Aumont,
C. Baccigalupi,
A. Balbi,
A. J. Banday,
R. B. Barreiro, [......],
P. Vielva,
F. Villa,
N. Vittorio,
L. A. Wade,
B. D. Wandelt,
N. Ysard,
D. Yvon,
A. Zacchei, S. Zahorecz,
A. Zonca
[show abstract]
[hide abstract]
ABSTRACT: We present the statistical properties of the first version of the Cold Core
Catalogue of Planck Objects (C3PO), in terms of their spatial distribution,
temperature, distance, mass, and morphology. We also describe the statistics of
the Early Cold Core Catalogue (ECC, delivered with the Early Release Compact
Source Catalogue, ERCSC) that is the subset of the 915 most reliable detections
of the complete catalogue. We have used the CoCoCoDeT algorithm to extract
10783 cold sources. Temperature and dust emission spectral index {\beta} values
are derived using the fluxes in the IRAS 100 \mum band and the three highest
frequency Planck bands. Temperature spans from 7K to 17K, and peaks around 13K.
Data are not consistent with a constant value of {\beta} over the all
temperature range. {\beta} ranges from 1.4 to 2.8 with a mean value around 2.1,
and several possible scenarios are possible, including {\beta}(T) and the
effect of multiple T components folded into the measurements. For one third of
the objects the distances are obtained. Most of the detections are within 2 kpc
in the Solar neighbourhood, but a few are at distances greater than 4 kpc. The
cores are distributed from the deep Galactic plane, despite the confusion, to
high latitudes (>30$^{\circle}$). The associated mass estimates range from 1 to
$10^5$ solar masses. Using their physical properties these cold sources are
shown to be cold clumps, defined as the intermediate cold sub-structures
between clouds and cores. These cold clumps are not isolated but mostly
organized in filaments associated with molecular clouds. The Cold Core
Catalogue of Planck Objects (C3PO) is the first unbiased all-sky catalogue of
cold objects. It gives an unprecedented statistical view to the properties of
these potential pre-stellar clumps and offers a unique possibility for their
classification in terms of their intrinsic properties and environment.
01/2011;
