We study the geometry and the physical conditions in the inner ( AU-scale ) circumstellar region around the young Herbig Be star MWC 147 using long-baseline spectro-interferometry in the near-infrared ( NIR K -band , VLTI/AMBER observations and PTI archive data ) as well as the mid-infrared ( MIR N -band , VLTI/MIDI observations ) .
The emission from MWC 147 is clearly resolved and has a characteristic physical size of \sim 1.3 AU and \sim 9 AU at 2.2 ~ { } \mu m and 11 ~ { } \mu m respectively ( Gaussian diameter ) .
The MIR emission reveals asymmetry consistent with a disk structure seen under intermediate inclination .
The spectrally dispersed AMBER and MIDI interferograms both show a strong increase in the characteristic size towards longer wavelengths , much steeper than predicted by analytic disk models assuming power-law radial temperature distributions .

We model the interferometric data and the spectral energy distribution of MWC 147 with 2-D , frequency-dependent radiation transfer simulations .
This analysis shows that models of spherical envelopes or passive irradiated Keplerian disks ( with vertical or curved puffed-up inner rim ) can easily fit the SED , but predict much lower visibilities than observed ; the angular size predicted by such models is 2 to 4 times larger than the size derived from the interferometric data , so these models can clearly be ruled out .
Models of a Keplerian disk with optically thick gas emission from an active gaseous disk ( inside the dust sublimation zone ) , however , yield a good fit of the SED and simultaneously reproduce the absolute level and the spectral dependence of the NIR and MIR visibilities .
We conclude that the NIR continuum emission from MWC 147 is dominated by accretion luminosity emerging from an optically thick inner gaseous disk , while the MIR emission also contains contributions from the outer , irradiated dust disk .