Herschel observations of Cen A: stellar heating of two extragalactic dust clouds Journal Articles uri icon

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  • We present the first results of a multi-wavelength survey, incoporating Herschel-SPIRE, Spitzer, GALEX and ATCA observations, of a 1 deg x 1 deg field centred on Centaurus A. As well as detecting the inner lobes of the active galactic nucleus (AGN) jet and counterjet, we have found two clouds, bright at sub-mm wavelengths, ~15 kpc from the centre of Cen A that are co-aligned with the jets. Flux measurements at Herschel wavelengths have proved vital in constraining fits to the Spectral Energy Distributions (SEDs). The clouds are well fit by a single-temperature, modified blackbody spectrum (beta=2) indicating that we are looking at two cold dust clouds on the outskirts of Cen A. The temperature and masses of the clouds are: T_{north} = 12.6^{+1.1}_{-1.2} K, T_{south} = 15.1^{+1.7}_{-1.6} K; log(M_{north} / M_o) = 5.8^{+0.2}_{-0.2}, log(M_{south} / M_o) = 5.6^{+0.2}_{-0.2} and the gas-dust ratio for both clouds is ~100. The measured values for the northern dust cloud are consistent with previous measurements from ISO while the southern cloud is a new sub-mm detection. The two dust clouds are located at the termini of the partial HI ring that surrounds Cen A which is also where the gas column density peaks... abridged


  • Auld, R
  • Smith, MWL
  • Bendo, G
  • Pohlen, M
  • Wilson, Christine D
  • Gomez, H
  • Cortese, L
  • Morganti, R
  • Baes, M
  • Boselli, A
  • Cooray, A
  • Davies, JI
  • Eales, S
  • Elbaz, D
  • Galametz, M
  • Isaak, K
  • Oosterloo, T
  • Page, M
  • Rigby, E
  • Spinoglio, L
  • Struve, C

publication date

  • March 1, 2012