Observations of galaxies at sub-millimeter wavelengths , where the emission is mainly due to cold dust , are required to constrain the dust physical properties and provide important insight on the gas content of galaxies .
We mapped NGC 1365 at 870 \mu m with LABOCA , the Large APEX Bolometer Camera , allowing us to probe the central mass concentration as well as the rate at which the gas flows to the center .
We obtained the dust physical properties both globally and locally for different locations in the galaxy .
A 20 K modified black body represents about 98 % of the total dust content of the galaxy , the rest can be represented by a warmer dust component of 40 K. The bar exhibits an east-west asymmetry in the dust distribution : The eastern bar is heavier than the western bar by more than a factor of 4 .
Integrating the dust SED , we derive a total infrared ( IR ) luminosity , L _ { TIR } , of 9.8 \times 10 ^ { 10 } { L } _ { \odot } leading to a dust-enshrouded star formation rate of { SFR } _ { TIR } \simeq 16.7 M _ { \odot } yr ^ { -1 } in NGC 1365 .
We derive the gas mass from the measurements of the dust emission leading to a CO-to-H _ { 2 } conversion factor of X _ { CO } \simeq 1.2 \times 10 ^ { 20 } mol cm ^ { -2 } ( K km s ^ { -1 } ) ^ { -1 } in the central disk including the bar .
Taking into account the metallicity variation , the central gas mass concentration is only \simeq 20 % at R < 40 \arcsec ( 3.6 kpc ) .
On the other hand , the time-scale with which the gas flows into the center , \simeq 300 Myr , is rather short .
This indicates that the current central mass in NGC 1365 is evolving fast due to the strong bar .