Discovery of massive star formation quenching by nonthermal effects in the center of NGC 1097

فاطمه طباطبایی (پژوهشکده نجوم پژوهشگاه دانش های بنیادی IPM )

Abstract: Observations show that massive star formation quenches first at centers of galaxies. To understand quenching mechanisms, we investigate the thermal and nonthermal energy balance in the central kpc of NGC1097- a prototypical galaxy undergoing quenching- and present a systematic study of the nuclear star formation efficiency and its dependencies. This region is dominated by the nonthermal pressure from the magnetic field, cosmic rays, and turbulence. A comparison of the mass-to-magnetic flux ratio of the molecular clouds shows that most of them are magnetically critical or supported against gravitational collapse needed to form cores of massive stars. Moreover, the star formation efficiency of the clouds drops with the magnetic field strength. Such an anti-correlation holds with neither the turbulent nor the thermal pressure. Hence, a progressive built up of the magnetic field results in high-mass stars forming inefficiently, and it may be the cause of the low-mass stellar population in the bulges of galaxies.

یکشنبه 29 مهر 1397، ساعت 15:00

دانشکده فیزیک، طبقه اول کلاس فیزیک 3