Planck intermediate results

Loading...
Thumbnail Image
Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2015-10
Major/Subject
Mcode
Degree programme
Language
en
Pages
23
p. A28
Series
ASTRONOMY AND ASTROPHYSICS, Volume 582, issue 1
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.
Description
VK: BIBCODE: 2015A&A...582A..28P; DOI: 10.1051/0004-6361/201424643; eprintid: arXiv:1407.5452
Keywords
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
Other note
Citation
Ade , P A R , Aghanim , N , Arnaud , M , Ashdown , M , Aumont , J , Baccigalupi , C , Banday , A J , Barreiro , R B , Bartolo , N , Battaner , E , Battye , R , Benabed , K , Bendo , G J , Benoit-Levy , A , Bernard , J -P , Bersanelli , M , Bielewicz , P , Bonaldi , A , Bonavera , L , Bond , J R , Borrill , J , Bouchet , F R , Burigana , C , Butler , R C , Calabrese , E , Cardoso , J -F , Catalano , A , Chamballu , A , Chary , R -R , Chen , X , Chiang , H C , Christensen , P R , Clements , D L , Colombo , L P L , Combet , C , Couchot , F , Coulais , A , Crill , B P , Curto , A , Cuttaia , F , Danese , L , Davies , R D , Davis , R J , de Bernardis , P , de Rosa , A , de Zotti , G , Delabrouille , J , Dickinson , C , Diego , J M , Lähteenmäki , A & Planck Collaboration 2015 , ' Planck intermediate results : XXV. The Andromeda galaxy as seen by Planck ' , Astronomy and Astrophysics , vol. 582 , no. 1 , 28 , pp. p. A28 . https://doi.org/10.1051/0004-6361/201424643