Lunch talk on Mar. 29, 2021

Cold gas in the nuclear region of the Andromeda galaxy --CO and [CII] mapping of selected regions in M31

Speaker:Zongnan Li (Nanjing University)

Venue:Video conference

Time:12:30 PM, Monday, Mar. 29, 2021

Abstract:

Circumnuclear regions of galaxies are vital places to study the interaction between the interstellar medium and the central supermassive black hole. As the second closest large spiral galaxy, M31 provides a unique close-up view for such an interaction. Here we present JCMT CO(3-2) and Herschel [CII] line observations of M31 nuclear region, covering the central 500 pc, with a resolution of ~60 pc. We found that the CO(3-2)/CO(1-0) ratio is close to unity in the center (compared to ~0.2 in the disk), indicating a higher cold gas temperature. Meanwhile, the [CII]/CO(3-2) ratio in higher in the center, suggesting a low gas density and strong radiation field. Furthermore, the [CII]/FIR ratio increases with radius, suggesting an increasing contribution from old stellar population to dust heating towards the center.

Report PPT:SWIFAR_Zongnan Li.pptx