tokens: χ 2 ), constrained by all of the photometric detections and upper limits from NIR to radio wavelengths (Figure 4 ). Parameters are analyzed under a Bayesian approach generating a posterior probability distribution function. The SED fitting failed to tightly constrain fracAGN given the lack of mid-IR photometric points (which differentiate between AGN and star-forming galaxies) and the loose constraint from the NIR. The posterior probability distribution suggests that the AGN component contributes at most ∼20% to the total IR luminosity, with the highest probability being assigned to a contribution of 0%–5%. This is consistent with the estimation from the L X / L FIR ratio in Section 3.1 . The model SED with the maximum 20% AGN fraction is also plotted in Figure 4 , which is inconsistent with the 100 μ m Herschel /PACS upper limit. Figure 4. Best-fit SED (black) from CIGALE PYTHON. Different components are color-coded. The data points from left to right are HST /WFC3 F110W+F160W, Spitzer /IRAC 3.6 μ m + 4.5 μ m, Herschel /PACS 100 μ m + 160 μ m, Herschel /SPIRE 250 μ m + 350 μ m + 500 μ m, APEX/LABOCA 870 μ m, SPT 1.4 mm + 2.0 mm, and ATCA 5.5 GHz + 2.1 GHz. We do not include the ATCA 9.0 GHz upper limit, which is less constraining, because the source may be resolved at this frequency. The inset plot shows the normalized probability distribution function of the AGN fraction in the total IR luminosity. The AGN most probably contributes less than 5%. The dash–dotted line is the model curve with the maximum 20% AGN contribution to the IR. In this model, the AGN contribution does not extend to the radio part of the SED. The ATCA radio continuum upper limits at 2.1 and 5.5 GHz are consistent with the FIR-to-radio correlation for star-forming galaxies. The radio part of the SED for radio-loud AGN would be at least a factor of ∼2 higher (e.g., Rush et al. 1996a , 1996b ; Morić et al. 2010 ). 3.3. Theoretical Expectations We have provided evidence that SPT0346-52 is star formation dominated in the IR. Since our SFR is mainly constrained by the FIR photometric data, L IR being almost all from star formation suggests that the inferred SFR reflects the true SFR. We examine whether this observed high SFR can be physically explained in the framework of “maximum” starbursts (Elmegreen 1999 ) where a substantial fraction of available gas is consumed to make stars. Following Tacconi et al. ( 2006 ), the maximum (“Schmidt-law”) SFR can be written aswhere Elmegreen ( 1999 ) defines as the star formation efficiency, f g is the gas fraction, M tot is the total (dynamical) mass of the system, t dyn is the dynamical time, and v c is the circular velocity in km s −1 . We use the definition in Tacconi et al. ( 2006 ), v c = 0.67 × v FWHM = 410 km s −1 ( v FWHM = 613 ± 30 km s −1 measured from the low- J CO(2-1) line; Aravena et al. 2016 ). Assuming a gas fraction of 0.3–0.8, we utilize the observed SFR of 3600 ± 300 M yr −1 to 19 19 Here we adopt the SFR
ner_tags: O O O O O O O O O O O O O O B-Wavelength O B-Wavelength O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Wavelength O O O O O O O O O O O O O O O B-Wavelength O O O O O O O O O O O O O O O O B-Wavelength O O O O O O O O O O O O O O O O O O O O O B-Wavelength O O B-Wavelength O O O O O O O O O O O O O O O O O O O O O O O O O O B-Wavelength I-Wavelength I-Wavelength B-Telescope B-Instrument O O O O O O O O B-Software B-Software O O O O O O O O O O O O B-Telescope B-Instrument B-Wavelength B-Telescope B-Instrument B-Wavelength I-Wavelength I-Wavelength O B-Wavelength I-Wavelength I-Wavelength B-Telescope B-Instrument B-Wavelength I-Wavelength I-Wavelength O B-Wavelength I-Wavelength I-Wavelength B-Telescope B-Instrument B-Wavelength I-Wavelength I-Wavelength O B-Wavelength I-Wavelength I-Wavelength O B-Wavelength I-Wavelength I-Wavelength B-Telescope B-Wavelength I-Wavelength I-Wavelength B-Telescope B-Wavelength I-Wavelength O B-Wavelength I-Wavelength O B-Telescope B-Wavelength I-Wavelength O B-Wavelength I-Wavelength O O O O O B-Telescope B-Wavelength I-Wavelength O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Wavelength O O O O O O O O O O O O O O O O O O O O O O O O B-Wavelength O O O O O O O O O O O O O O O O O B-Telescope B-Wavelength O O O O B-Wavelength O B-Wavelength I-Wavelength O O O O B-Wavelength O O O O O B-Wavelength O O O O O B-Wavelength O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation O B-Citation O B-Citation I-Citation I-Citation I-Citation O O O O O O O O O B-CelestialObject O O O O O O B-Wavelength O O O O O O O O B-Wavelength O O O B-Wavelength O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O B-Model O O O O O B-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation B-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula O B-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula O O O O B-Wavelength I-Wavelength O B-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O