Lunch talk on Mar. 18, 2024

Revisiting the Nuclear Environment of our Neighbor M31 -- A tale of molecular gas

Speaker: Zongnan Li (NAOC)

Venue: Video Conference

Time: 12:30 PM, Monday, Mar. 18, 2024

Abstract: 

Galactic circumnuclear environments, in which the multiphase interstellar medium (ISM) and various stellar populations are coupled under the gravitational potential of a supermassive black hole (SMBH), are an important testbed for a variety of astronomical processes. Thanks to its proximity, M31 provides a unique perspective for studying a galactic circumnuclear environment. Central to this environments is the so-called nuclear spiral across the central 1 kpc, surrounded by a dusty nuclear ring. We present the first complete mapping of molecular gas in the nuclear spiral as well as a portion of the nuclear ring. The physical conditions of the molecular gas in this region are analyzed and compared with that in the disk. It is found that the CO line ratio is higher in the nuclear region, indicating that the gas kinetic temperature is higher in the nuclear region. In addition, it is found that the nuclear region exhibits a much higher Virial parameter than the galactic disk, suggesting that the gas clump in this region is rather pressure bound or transient. The notable distinction in the molecular gas environment between the nuclear region and the disk carries significant implications for the physical conditions within this particular region.

Report PPT:  SWIFAR_Zongnan Li.pptx