Mapping far-IR emission from the central kiloparsec of NGC 1097

July 2010 • 2010A&A...518L..59S

Authors • Sandstrom, K. • Krause, O. • Linz, H. • Schinnerer, E. • Dumas, G. • Meidt, S. • Rix, H. -W. • Sauvage, M. • Walter, F. • Kennicutt, R. C. • Calzetti, D. • Appleton, P. • Armus, L. • Beirão, P. • Bolatto, A. • Brandl, B. • Crocker, A. • Croxall, K. • Dale, D. • Draine, B. T. • Engelbracht, C. • Gil de Paz, A. • Gordon, K. • Groves, B. • Hao, C. -N. • Helou, G. • Hinz, J. • Hunt, L. • Johnson, B. D. • Koda, J. • Leroy, A. • Murphy, E. J. • Rahman, N. • Roussel, H. • Skibba, R. • Smith, J. -D. • Srinivasan, S. • Vigroux, L. • Warren, B. E. • Wilson, C. D. • Wolfire, M. • Zibetti, S.

Abstract • 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.

Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Links

• PREPRINT http://arxiv.org/abs/1005.1959
• NED https://ned.ipac.caltech.edu/uri/NED::InRefcode/2010A%26A...518L..59S
• POSTSCRIPT https://www.aanda.org/10.1051/0004-6361/201014583/postscript
• ELECTR https://doi.org/10.1051%2F0004-6361%2F201014583
• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2010A%26A...518L..59S
• PDF https://www.aanda.org/10.1051/0004-6361/201014583/pdf
• DATA http://archives.esac.esa.int/hsa/whsa/?ACTION=PUBLICATION&ID=2010A%26A...518L..59S
• DATA https://irsa.ipac.caltech.edu/bibdata/2010/S/2010A&A...518L..59S.html