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Mapping and mass measurement of the cold dust in NGC 205 with Spitzer

Marleau, F. R. and Noriega-Crespo, A. and Misselt, K. A. and Gordon, K. D. and Engelbracht, C. W. and Rieke, G. H. and Barmby, P. and Willner, S. P. and Mould, J. and Gehrz, R. D. and Woodward, C. E. (2006) Mapping and mass measurement of the cold dust in NGC 205 with Spitzer. Astrophysical Journal, 646 (2). pp. 929-938. ISSN 0004-637X. http://resolver.caltech.edu/CaltechAUTHORS:MARapj06

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Abstract

We present observations at 3.6, 4.5, 5.8, 8, 24, 70, and 160 μm of NGC 205, the dwarf elliptical companion of M31, obtained with the Spitzer Space Telescope. The point-source-subtracted images at 8 and 24 μm display a complex and fragmented infrared emission coming from both very small dust particles and larger grains. The extended dust emission is spatially concentrated in three main emission regions, seen at all wavelengths from 8 to 160 μm. These regions lie approximately along NGC 205's semimajor axis and range from ~100 to 300 pc in size. On the basis of our mid-/far-infrared flux density measurements alone, we derive a total dust mass estimate on the order of 3.2 x 10^(4) M☉, mainly at a temperature of similar to 20 K. The gas mass associated with this component matches the predicted mass returned by the dying stars from the last burst of star formation in NGC 205 (~0.5 Gyr ago). Analysis of the Spitzer data combined with previous 1.1 mm observations over a small central or "Core" region (18" diameter) suggests the presence of very cold (T ~ 12 K) dust and a dust mass about 16 times higher than is estimated from the Spitzer measurements alone. Assuming a gas-to-dust mass ratio of 100, these two data sets, i.e., with and without the millimeter observations, suggest a total gas mass in the range from 3.2 x 10^(6) to 5 x 10^(7) M☉.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1086/504975DOIUNSPECIFIED
ORCID:
AuthorORCID
Mould, J.0000-0003-3820-1740
Additional Information:© 2006 American Astronomical Society. Received 2006 January 27; accepted 2006 April 8. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory (JPL), California Institute of Technology, under NASA contract 1407. Support for this work was provided by NASA and through JPL contract 1255094. We thank the referee for her/his careful reading of the manuscript.
Funders:
Funding AgencyGrant Number
NASA1407
Jet Propulsion Laboratory1255094
Subject Keywords:dust, extinction; galaxies: dwarf; galaxies: individual (NGC 205); galaxies: ISM; infrared: galaxies; infrared: ISM; ISM: structure
Record Number:CaltechAUTHORS:MARapj06
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:MARapj06
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:12060
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:22 Oct 2008 15:45
Last Modified:05 Oct 2017 21:02

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