NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-07-16 T15:56:13 PDT
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For refcode 2001A&A...379..823K:
Retrieve 62 NED objects in this reference.
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Copyright by European Southern Observatory (ESO). Reproduced by permission
2001A&A...379..823K Infrared to millimetre photometry of ultra-luminous IR galaxies: New evidence favouring a 3-stage dust model U. Klaas, M. Haas, S. A. H. Muller, R. Chini, B. Schulz, I. Coulson, H. Hippelein, K. Wilke, M. Albrecht and D. Lemke Max-Planck-Institut fur Astronomie (MPIA), Konigstuhl 17, 69117 Heidelberg, Germany Astronomisches Institut, Ruhr-Universitat Bochum, 44780 Bochum, Germany ISO Data Centre, Astrophysics Division, Space Science Dep. of ESA, Villafranca, PO Box 50727, 28080 Madrid, Spain Joint Astronomy Centre, 660 N. Aohuku Place, University Park, Hilo 96720, Hawaii, USA Received 22 December 2000/Accepted 24 September 2001 Abstract. Infrared to millimetre spectral energy distributions (SEDs) have been obtained for 41 bright ultra-luminous infrared galaxies (ULIRGs). The observations were carried out with ISOPHOT between 10 and 200 microns and supplemented for 16 sources with JCMT/SCUBA at 450 and 850 microns and with SEST at 1.3 mm. In addition, seven sources were observed at 1.2 and 2.2 microns with the 2.2 m telescope on Calar Alto. These new SEDs represent the most complete set of infrared photometric templates obtained so far on ULIRGs in the local universe. The SEDs peak at 60-100 microns and show often a quite shallow Rayleigh-Jeans tail. Fits with one single modified blackbody yield a high FIR opacity and small dust emissivity exponent {beta} < 2. However, this concept leads to conflicts with several other observational constraints, like the low PAH extinction or the extended filamentary optical morphology. A more consistent picture is obtained using several dust components with {beta} = 2, low to moderate FIR opacity and cool (50 K > T > 30 K) to cold (30 K > T > 10 K) temperatures. This provides evidence for two dust stages, the cool starburst dominated one and the cold cirrus-like one. The third stage with several hundred Kelvin warm dust is identified in the AGN dominated ULIRGs, showing up as a NIR-MIR power-law flux increase. While AGNs and SBs appear indistinguishable at FIR and submm wavelengths, they differ in the NIR-MIR. This suggests that the cool FIR emitting dust is not related to the AGN, and that the AGN only powers the warm and hot dust. In comparison with optical and MIR spectroscopy, a criterion based on the SED shapes and the NIR colours is established to reveal AGNs among ULIRGs. Also the possibility of recognising evolutionary trends among the ULIRGs via the relative amounts of cold, cool and warm dust components is investigated. Key words: infrared: galaxies - galaxies: active, evolution, fundamental parameters, photometry, starbursts
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