Author/s: C. Ramos Almeida, M. Sanchez-Portal, A. M. Perez-Garcia, J. A. Acosta-Pulido, M. Castillo, A. Asensio Ramos, J. I. Gonzalez-Serrano, A. Alonso-Herrero, J. M. Rodriguez Espinosa, E. Hatziminaoglou, D. Coia, I. Valtchanov, M. Povic, P. Esquej, C. Packham and B. Altieri
Reference: Ramos Almeida et al. 2011, MNRAS letters, in press. | Link
We report far-infrared (FIR) imaging of the Seyfert 2 galaxy NGC 3081 in the range 70- 500 μm, obtained with an unprecedented angular resolution, using the Herschel Space Observatory instruments PACS and SPIRE. The 11 kpc (∼70′′) diameter star-forming ring of the galaxy appears resolved up to 250 μm. We extracted infrared (1.6-500 μm) nuclear fluxes, that is active nucleus-dominated fluxes, and fitted them with clumpy torus models, which successfully reproduce the FIR emission with small torus sizes. Adding the FIR data to the near- and mid-infrared spectral energy distribution (SED) results in a torus radial extent of Ro=4±2 pc, as well as in a flat radial distribution of the clouds (i.e. the q parameter). At wavelengths beyond 200 μm, cold dust emission at T=28±1 K from the circumnuclear star-forming ring of 2.3 kpc (∼15′′) in diameter starts making a contribution to the nuclear emission. The dust in the outer parts of the galaxy is heated by the interstellar radiation field (19±3 K).