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Dust and Gas in the Magellanic Clouds from the HERITAGE Herschel Key Project. I. Dust Properties and Insights into the Origin of the Submm Excess Emission
- Source :
- The Astrophysical journal letters, The Astrophysical journal letters, Bristol : IOP Publishing, 2014, 797 (2), pp.85. ⟨10.1088/0004-637X/797/2/85⟩, The Astrophysical journal letters, 2014, 797 (2), pp.85. ⟨10.1088/0004-637X/797/2/85⟩, Astronomy & Astrophysics, Artículos CONICYT, CONICYT Chile, instacron:CONICYT, ASTROPHYSICAL JOURNAL
- Publication Year :
- 2014
-
Abstract
- The dust properties in the Large and Small Magellanic Clouds are studied using the HERITAGE Herschel Key Project photometric data in five bands from 100 to 500 micron. Three simple models of dust emission were fit to the observations: a single temperature blackbody modified by a power- law emissivity (SMBB), a single temperature blackbody modified by a broken power-law emissivity (BEMBB), and two blackbodies with different temperatures, both modified by the same power-law emissivity (TTMBB). Using these models we investigate the origin of the submm excess; defined as the submillimeter (submm) emission above that expected from SMBB models fit to observations < 200 micron. We find that the BEMBB model produces the lowest fit residuals with pixel-averaged 500 micron submm excesses of 27% and 43% for the LMC and SMC, respectively. Adopting gas masses from previous works, the gas-to-dust ratios calculated from our the fitting results shows that the TTMBB fits require significantly more dust than are available even if all the metals present in the interstellar medium (ISM) were condensed into dust. This indicates that the submm excess is more likely to be due to emissivity variations than a second population of colder dust. We derive integrated dust masses of (7.3 +/- 1.7) x 10^5 and (8.3 +/- 2.1) times 10^4 M(sun) for the LMC and SMC, respectively. We find significant correlations between the submm excess and other dust properties; further work is needed to determine the relative contributions of fitting noise and ISM physics to the correlations.<br />20 pages, 9 figures, accepted for publication in the ApJ
- Subjects :
- [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE]
[PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM]
Population
FOS: Physical sciences
Astrophysics
galaxies [infrared]
[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]
GALAXY EVOLUTION SAGE
Emissivity
Black-body radiation
Magellanic clouds
ABSORPTION-COEFFICIENT
education
ComputingMilieux_MISCELLANEOUS
CARBON ANALOG GRAINS
Physics
education.field_of_study
general [ISM]
LOW-METALLICITY
ISM [infrared]
Astronomy and Astrophysics
Astrophysics - Astrophysics of Galaxies
Interstellar medium
SPECTRAL ENERGY-DISTRIBUTION
[PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA]
Physics and Astronomy
TEMPERATURE-DEPENDENCE
13. Climate action
Space and Planetary Science
Astrophysics of Galaxies (astro-ph.GA)
MOLECULAR CLOUDS
MILKY-WAY
ULTRAVIOLET EXTINCTION
INTERSTELLAR DUST
Noise (radio)
Dust emission
Subjects
Details
- Language :
- English
- ISSN :
- 20418205, 20418213, and 0004637X
- Database :
- OpenAIRE
- Journal :
- The Astrophysical journal letters, The Astrophysical journal letters, Bristol : IOP Publishing, 2014, 797 (2), pp.85. ⟨10.1088/0004-637X/797/2/85⟩, The Astrophysical journal letters, 2014, 797 (2), pp.85. ⟨10.1088/0004-637X/797/2/85⟩, Astronomy & Astrophysics, Artículos CONICYT, CONICYT Chile, instacron:CONICYT, ASTROPHYSICAL JOURNAL
- Accession number :
- edsair.doi.dedup.....3f1691e36df54581a5533bd28ba394d4