Circum-nuclear eccentric gas flow in the Galactic Center revealed by ALMA CMZ Exploration Survey (ACES)
2025-06-13
Yoshiaki Sofue, Tomoharu Oka, Steven N. Longmore, Daniel Walker, Adam Ginsburg, Jonathan D. Henshaw, John Bally, Ashley T. Barnes, Cara Battersby, Laura Colzi, Paul Ho, Izaskun Jimenez-Serra, J. M. Diederik Kruijssen, Elizabeth Mills, Maya A. Petkova, Mattia C. Sormani, Jennifer Wallace, Jairo Armijos-Abendaño, Katarzyna M. Dutkowska, Rei Enokiya, Pablo García, Savannah Gramze, Christian Henkel, Pei-Ying Hsieh, Yue Hu, Katharina Immer, Yuhei Iwata, Janik Karoly, Ralf S. Klessen, Kotaro Kohno, Mark R. Krumholz, Dani Lipman, Mark R. Morris, Francisco Nogueras-Lara, Jaime E. Pineda, Sergio Martín, Miguel Angel Requenatorres, Víctor M. Rivilla, Denise Riquelme-Vásquez, Álvaro Sánchez-Monge, Miriam G. Santa-Maria, Howard A. Smith, Volker Tolls, Q. Daniel Wang
We analyze the CS (J=2-1) line cube from the internal data release obtained by the large-scale program «ALMA CMZ Exploration Survey (ACES)» to investigate the kinematic structure of the innermost pc region of the Galaxy, which contains the high-velocity compact cloud (HVCC) at (hereafter G0.02). The longitude-velocity diagram (LVD) of the cloud draws an elliptical structure, which is interpreted as an orbital trajectory in the space of a noncircular (eccentric) motion of the molecular gas in the gravitational potential of an extended mass distribution in the central 10 pc of the Galaxy. We argue that G0.02 is a kinematic tracer of the inner potential, a rare case of a dense gas following an eccentric orbit in the nuclear gravitational field.