Issue |
A&A
Volume 518, July-August 2010
Herschel: the first science highlights
|
|
---|---|---|
Article Number | L59 | |
Number of page(s) | 5 | |
Section | Letters | |
DOI | https://doi.org/10.1051/0004-6361/201014583 | |
Published online | 16 July 2010 |
Letter to the Editor
Mapping far-IR emission from the central kiloparsec of NGC 1097*
1
Max-Planck-Institut für Astronomie, Königstuhl 17,
69117 Heidelberg, Germany e-mail: sandstrom@mpia.de
2
CEA/DSM/DAPNIA/Service d'Astrophysique, UMR AIM, CE Saclay, 91191
Gif sur Yvette Cedex, France
3
Institute of Astronomy, University of Cambridge, Madingley Road,
Cambridge CB3 0HA, UK
4
Department of Astronomy, University of Massachusetts, Amherst, MA
01003, USA
5
NASA Herschel Science Center, IPAC, California Institute of
Technology, Pasadena, CA 91125, USA
6
Spitzer Science Center, California Institute of Technology, MC
314-6, Pasadena, CA 91125, USA
7
Department of Astronomy, University of Maryland, College Park, MD
20742, USA
8
Leiden Observatory, Leiden University, PO Box 9513, 2300 RA
Leiden, The Netherlands
9
Department of Physics and Astronomy, University of
Toledo, Toledo, OH 43606, USA
10
Department of Physics & Astronomy, University of Wyoming,
Laramie, WY 82071, USA
11
Department of Astrophysical Sciences, Princeton University,
Princeton, NJ 08544, USA
12
Steward Observatory, University of Arizona, Tucson, AZ 85721, USA
13
Departamento de Astrofisica, Facultad de Ciencias Fisicas,
Universidad Complutense Madrid, Ciudad Universitaria, Madrid, 28040,
Spain
14
Space Telescope Science Institute, 3700 San Martin Drive,
Baltimore, MD 21218, USA
15
Tianjin Astrophysics Center, Tianjin Normal University, Tianjin
300387, China
16
INAF - Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5,
50125 Firenze, Italy
17
Department of Physics and Astronomy, SUNY Stony Brook, Stony
Brook, NY 11794-3800, USA
18
Hubble Fellow, National Radio Astronomy Observatory, 520 Edgemont
Road, Charlottesville, VA 22903, USA
19
Institut d'Astrophysique de Paris, UMR7095 CNRS, Université
Pierre & Marie Curie, 98 bis Boulevard Arago, 75014 Paris, France
20
ICRAR, M468, University of Western Australia, 35 Stirling Hwy,
Crawley, WA 6009, Australia
21
Department of Physics & Astronomy, McMaster University,
Hamilton, Ontario L8S 4M1, Canada
Received:
30
March
2010
Accepted:
29
April
2010
Using photometry of NGC 1097 from the Herschel PACS (Photodetector Array Camera and Spectrometer) instrument, we study the resolved properties of thermal dust continuum emission from a circumnuclear starburst ring with a radius ~900 pc. These observations are the first to resolve the structure of a circumnuclear ring at wavelengths that probe the peak (i.e. λ ~ 100 μm) of the dust spectral energy distribution. The ring dominates the far-infrared (far-IR) emission from the galaxy – the high angular resolution of PACS allows us to isolate the ring's contribution and we find it is responsible for 75, 60 and 55% of the total flux of NGC 1097 at 70, 100 and 160 μm, respectively. We compare the far-IR structure of the ring to what is seen at other wavelengths and identify a sequence of far-IR bright knots that correspond to those seen in radio and mid-IR images. The mid- and far-IR band ratios in the ring vary by less than ±20% azimuthally, indicating modest variation in the radiation field heating the dust on ~600 pc scales. We explore various explanations for the azimuthal uniformity in the far-IR colors of the ring including a lack of well-defined age gradients in the young stellar cluster population, a dominant contribution to the far-IR emission from dust heated by older (>10 Myr) stars and/or a quick smoothing of local enhancements in dust temperature due to the short orbital period of the ring. Finally, we improve previous limits on the far-IR flux from the inner ~600 pc of NGC 1097 by an order of magnitude, providing a better estimate of the total bolometric emission arising from the active galactic nucleus and its associated central starburst.
Key words: infrared: galaxies / galaxies: star formation / galaxies: individual: NGC 1097 / dust, extinction
© ESO, 2010
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