ترغب بنشر مسار تعليمي؟ اضغط هنا

Infalling motions were detected and modeled toward this source. A mean infall velocity of 0.5 km/s with an infall mass rate of 5x10^-3 Solar masses per year was obtained. Also, a previously estimated value for the magnetic field strength in the plane of the sky was refined to be 855 micro Gauss which we used to calculate a mass-to-magnetic flux ratio of 1.9, or super-critical. The virial mass from turbulent motions was also calculated finding Mvir=563 solar masses, which gives a ratio of Msubmm/Mvir=5.9. Both values strongly suggest that this clump must be in a state of gravitational collapse.
We present results from 4.8 GHz VLA and Global-VLBI observations of the northern half of the moderate FIR luminosity (median L_IR = 10^11.01 L_Sol) COLA sample of star-forming galaxies. VLBI sources are detected in a high fraction (20/90) of the gala xies observed. The radio luminosities of these cores (~10^21 W/Hz) are too large to be explained by radio supernovae or supernova remnants and we argue that they are instead powered by AGN. These sub-parsec scale radio cores are preferentially detected toward galaxies whose VLA maps show bright 100-500 parsec scale nuclear radio components. Since these latter structures tightly follow the FIR to radio-continuum correlation for star-formation we conclude that the AGN powered VLBI sources are associated with compact nuclear starburst environments. The implications for possible starburst-AGN connections are discussed. The detected VLBI sources have a relatively narrow range of radio luminosity consistent with models in which intense compact Eddington-limited starbursts regulate the gas supply onto a central super-massive black hole. The high incidence of AGN radio cores in compact starbursts suggests little or no delay between the starburst phase and the onset of AGN activity.
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا