2018A&A...615A..18R


Query : 2018A&A...615A..18R

2018A&A...615A..18R - Astronomy and Astrophysics, volume 615A, 18-18 (2018/7-1)

A NIKA view of two star-forming infrared dark clouds: Dust emissivity variations and mass concentration.

RIGBY A.J., PERETTO N., ADAM R., ADE P., ANDRE P., AUSSEL H., BEELEN A., BENOIT A., BRACCO A., BIDEAUD A., BOURRION O., CALVO M., CATALANO A., CLARK C.J.R., COMIS B., DE PETRIS M., DESERT F.-X., DOYLE S., DRIESSEN E.F.C., GOUPY J., KRAMER C., LAGACHE G., LECLERCQ S., LESTRADE J.-F., MACIAS-PEREZ J.F., MAUSKOPF P., MAYET F., MONFARDINI A., PASCALE E., PEROTTO L., PISANO G., PONTHIEU N., REVERET V., RITACCO A., ROMERO C., ROUSSEL H., RUPPIN F., SCHUSTER K., SIEVERS A., TRIQUENEAUX S., TUCKER C. and ZYLKA R.

Abstract (from CDS):


Context. The thermal emission of dust grains is a powerful tool for probing cold, dense regions of molecular gas in the interstellar medium, and so constraining dust properties is key to obtaining accurate measurements of dust mass and temperature.
Aims. By placing constraints on the dust emissivity spectral index, β, towards two star-forming infrared dark clouds - SDC18.888-0.476 and SDC24.489-0.689 - we aim to evaluate the role of mass concentration in the associated star-formation activity.
Methods. We exploited the simultaneous 1.2 and 2.0mm imaging capability of the NIKA camera on the IRAM 30 m telescope to construct maps of β for both clouds, and by incorporating Herschel observations, we created H2 column density maps with 13'' angular resolution.
Results. While we find no significant systematic radial variations around the most massive clumps in either cloud on ≥0.1pc scales, their mean β values are significantly different, with β=2.07±0.09{bar}β(random)±0.25 (systematic) for SDC18.888-0.476 and β=1.71±0.09{bar}β(random)±0.25 (systematic) for SDC24.489-0.689. These differences could be a consequence of the very different environments in which both clouds lie, and we suggest that the proximity of SDC18.888-0.476 to the W39 HII region may raise β on scales of ∼1pc. We also find that the mass in SDC24.489-0.689 is more centrally concentrated and circularly symmetric than in SDC18.888-0.476, and is consistent with a scenario in which spherical globally-collapsing clouds concentrate a higher fraction of their mass into a single core than elongated clouds that will more easily fragment, distributing their mass into many cores.
Conclusions. We demonstrate that β variations towards interstellar clouds can be robustly constrained with high signal-to-noise ratio (S/N) NIKA observations, providing more accurate estimates of their masses. The methods presented here will be applied to the Galactic Star Formation with NIKA2 (GASTON) guaranteed time large programme, extending our analysis to a statistically significant sample of star-forming clouds.

Abstract Copyright: © ESO 2018

Journal keyword(s): stars: formation - submillimeter: ISM - ISM: clouds - dust, extinction - ISM: structure

VizieR on-line data: <Available at CDS (J/A+A/615/A18): list.dat fits/*>

Simbad objects: 10

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Number of rows : 10
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 Barnard 213 DNe 04 20 51 +27 16.3           ~ 190 0
2 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 4009 0
3 LDN 1544 DNe 05 04 16.6 +25 10 48           ~ 793 0
4 SDC G18.888-0.476 DNe 18 27 08.31 -12 41 38.9           ~ 6 0
5 GRS G018.88 -00.48 Rad 18 27 10.73 -12 40 07.5           ~ 29 0
6 SDC G24.489-0.689 DNe 18 38 25.25 -07 49 28.9           ~ 4 0
7 UGPS J183827.06-074912.1 NIR 18 38 27.0737875536 -07 49 12.139340808           ~ 2 0
8 MHO 3240 EmO 18 38 27.2 -07 49 11           ~ 3 0
9 LDN 1157 DNe 20 39 06.4 +68 02 13           ~ 545 0
10 NAME Gould Belt PoG ~ ~           ~ 814 1

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2022.09.26-15:03:28

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