The nuclear star-forming region in the NGC1365 with ALMA observation

We have used the ALMA to map the CO(1-0, 2-1) and its continuum for the starburst-Seyfert nucleus of the barred spiral galaxy NGC 1365. The beam sizes of the 12CO(1-0) and 12CO(2-1) emission maps are about 2.3 and 0.9 arcsec square, corresponding to 700 and 310 pc^2, respectively. We find a circumnuclear gas ring and several CO clumps in the central 3 kpc, which show intense star formation activity. The surface density of H2 mass in these clumps are about 0.7-1.0 \times 10^4 $M_sun$ pc^{-2}. The molecular ring shows morphological and kinematical signs of bar-driven gas dynamics. In addition to these CO clumps, we also detect two bright continuum regions in 1.3 and 3mm bands, which are previously identified as massive star cluster embedded in the dust cocoon. After performing the SED fitting from near-infrared to radio (cm) bands with CIGALE code, we find the dust mass and stellar mass are about 1.7 and 5.0 \times 10^6 $M_sun$. And one third of the stellar mass are shown as very young (<10 Myr) population, which means that amount of pre- main sequence stars are embedded in the dust. The specific SFR in these two regions are about 100 times than in the metal-poor galaxies in nearby and z ∼ 1.0 universe. However, the radio spectral index are -0.15, which are different with the synchrotron radiation. We will find the explanation.