Herschel Dust Emission as a Probe of Starless Cores Mass: MCLD 123.5+24.9 of the Polaris Flare

Authors

Gururaj Anil Wagle, University of KentuckyFollow
Thomas H. Troland, University of KentuckyFollow
Gary J. Ferland, University of KentuckyFollow
Nicholas P. Abel, University of Cincinnati

Abstract

We present newly processed archival Herschel images of molecular cloud MCLD 123.5+24.9 in the Polaris Flare. This cloud contains five starless cores. Using the spectral synthesis code Cloudy, we explore uncertainties in the derivation of column densities, and hence masses of molecular cores from Herschel data. We first consider several detailed grain models that predict far-infrared grain opacities. Opacities predicted by the models differ by more than a factor of two, leading to uncertainties in derived column densities by the same factor. Then we consider uncertainties associated with the modified blackbody fitting process used by observers to estimate column densities. For high column density clouds (N(H) ≫ 1 x 10²² cm⁻²), this fitting technique can underestimate column densities by about a factor of three. Finally, we consider the virial stability of the five starless cores in MCLD 123.5+24.9. All of these cores appear to have strongly sub-virial masses, assuming, as we argue, that ¹³CO line data provide reliable estimates of velocity dispersions. Evidently, they are not self-gravitating, so it is no surprise that they are starless.

Document Type

Article

Publication Date

8-4-2015

Notes/Citation Information

Published in The Astrophysical Journal, v. 809, no. 1, 17, p. 1-14.

© 2015. The American Astronomical Society. All rights reserved.

The copyright holders have granted the permission for posting the article here.

Digital Object Identifier (DOI)

https://doi.org/10.1088/0004-637X/809/1/17

Funding Information

G.J.F. acknowledges support by NSF (1108928, 1109061, and 1412155), NASA (10-ATP10-0053, 10-ADAP10-0073, NNX12AH73G, and ATP13-0153), and STScI (HST-AR- 13245, GO-12560, HST-GO-12309, GO-13310.002-A, and HST-AR-13914), and to the Leverhulme Trust for support via the award of a Visiting Professorship at Queens University Belfast (VP1-2012-025).

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Repository Citation

Wagle, Gururaj Anil; Troland, Thomas H.; Ferland, Gary J.; and Abel, Nicholas P., "Herschel Dust Emission as a Probe of Starless Cores Mass: MCLD 123.5+24.9 of the Polaris Flare" (2015). Physics and Astronomy Faculty Publications. 366.
https://uknowledge.uky.edu/physastron_facpub/366