Planck intermediate results XXV : The Andromeda galaxy as seen by Planck

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Ade , P A R , Juvela , M , Keihänen , E , Kurki-Suonio , H , Lähteenmäki , A , Suur-Uski , A -S , Valiviita , J & Planck Collaboration 2015 , ' Planck intermediate results XXV : The Andromeda galaxy as seen by Planck ' , Astronomy & Astrophysics , vol. 582 , A28 , pp. A28 . https://doi.org/10.1051/0004-6361/201424643

Title: Planck intermediate results XXV : The Andromeda galaxy as seen by Planck
Author: Ade, P. A. R.; Juvela, M.; Keihänen, E.; Kurki-Suonio, H.; Lähteenmäki, A.; Suur-Uski, A. -S.; Valiviita, J.; Planck Collaboration
Contributor organization: Department of Physics
Helsinki Institute of Physics
Date: 2015-10
Language: eng
Number of pages: 23
Belongs to series: Astronomy & Astrophysics
ISSN: 1432-0746
DOI: https://doi.org/10.1051/0004-6361/201424643
URI: http://hdl.handle.net/10138/233350
Abstract: The Andromeda galaxy (M 31) is one of a few galaxies that has sufficient angular size on the sky to be resolved by the Planck satellite. Planck has detected M 31 in all of its frequency bands, and has mapped out the dust emission with the High Frequency Instrument, clearly resolving multiple spiral arms and sub-features. We examine the morphology of this long-wavelength dust emission as seen by Planck, including a study of its outermost spiral arms, and investigate the dust heating mechanism across M 31. We find that dust dominating the longer wavelength emission (greater than or similar to 0.3 mm) is heated by the diffuse stellar population (as traced by 3.6 mu m emission), with the dust dominating the shorter wavelength emission heated by a mix of the old stellar population and star-forming regions (as traced by 24 mu m emission). We also fit spectral energy distributions for individual 5' pixels and quantify the dust properties across the galaxy, taking into account these different heating mechanisms, finding that there is a linear decrease in temperature with galactocentric distance for dust heated by the old stellar population, as would be expected, with temperatures ranging from around 22 K in the nucleus to 14 K outside of the 10 kpc ring. Finally, we measure the integrated spectrum of the whole galaxy, which we find to be well-fitted with a global dust temperature of (18.2 +/- 1.0) K with a spectral index of 1.62 +/- 0.11 (assuming a single modified blackbody), and a significant amount of free-free emission at intermediate frequencies of 20-60 GHz, which corresponds to a star formation rate of around 0.12 M-circle dot yr(-1). We find a 2.3 sigma detection of the presence of spinning dust emission, with a 30 GHz amplitude of 0.7 +/- 0.3 Jy, which is in line with expectations from our Galaxy.
Subject: galaxies: individual: Messier 31
galaxies: structure
galaxies: ISM
submillimeter: galaxies
radio continuum: galaxies
MULTIBAND IMAGING PHOTOMETER
RADIO-CONTINUUM SURVEY
PRE-LAUNCH STATUS
SPITZER-SPACE-TELESCOPE
FAR-INFRARED LUMINOSITY
SPINNING DUST EMISSION
RESOLUTION IRAS MAPS
STAR-FORMATION RATES
LOCAL GROUP GALAXIES
COMPLETE CO SURVEY
115 Astronomy, Space science
Peer reviewed: Yes
Usage restriction: openAccess
Self-archived version: publishedVersion


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