Mapping far-IR emission from the central kiloparsec of NGC 1097 Academic Article uri icon

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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. lambda ~ 100 micron) 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 micron, 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.

authors

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

publication date

  • July 2010