The Galactic Center arms inferred from the ALMA CMZ Exploration Survey (ACES)
Artikel i vetenskaplig tidskrift, 2025
Analyzing longitude-velocity diagrams (LVDs) in the CS (J = 2-1) and (HCN)-C-13 (J = 1-0) molecular lines from the internal release data of the ALMA Central Molecular Zone (CMZ) Exploration Survey and in the (CO)-C-13 (J = 1-0) line from the Nobeyama Galactic Center (GC) survey, we identify six GC arms as prominent straight LV ridges. In addition to the currently known Arms I to IV, we identify a new inner arm, Arm V, and further highlight the circumnuclear disk (CND) as Arm VI. Integrated intensity maps of the arms on the sky suggest that most of the arms compose ring-like structures inclined from the Galactic plane. We determine the radii (curvatures) of the arms using the velocity-gradient (dv/dl) method, assuming that the arms are rotating in circular orbits at a constant velocity of similar to 150 km s(-1). We show that Arms I and II compose the main ring structure of the CMZ with radii similar to 100-120 pc; Arm III is a dense arm 42 pc from the GC; Arm IV is a clear and narrow arm 20 pc from the GC; and Arm V is a faint, long arm of 8.2 pc radius. We show that the CND comprises the sixth arm, Arm VI, of radius similar to 2.3 pc associated with bifurcated spiral fins. We also discuss the association of the 20 and 50 km s(-1) clouds with these arms. The radii of the arms fall on an empirical relation R similar to 630 (2/5)(N) for N=1 (Arm I) to 6 (VI), suggesting discrete rings or a logarithmic spiral with pitch angle similar to 22 degrees. The vertical full extent of the arm increases with radius and is represented by z similar to 0.7 (R/1 pc)(0.7) pc. The tilt angle of the arms from the Galactic plane, or the warping, increases rapidly toward the GC.
ISM: molecules
ISM: kinematics and dynamics
ISM: clouds
Galaxy: Center
Galaxy: structure
Författare
Yoshiaki Sofue
University of Tokyo
Tomoharu Oka
Keio University
Steven N. Longmore
COOL Research DAO
Liverpool John Moores University
Daniel Walker
University of Manchester
Adam Ginsburg
University of Florida
Jonathan D. Henshaw
Liverpool John Moores University
Max-Planck-Gesellschaft
John Bally
University of Colorado
Ashley T. Barnes
European Southern Observatory (ESO)
Cara Battersby
University of Connecticut
Laura Colzi
Consejo Superior de Investigaciones Científicas (CSIC)
Paul Ho
National Taiwan University
Izaskun Jimenez-Serra
Consejo Superior de Investigaciones Científicas (CSIC)
J. M. Diederik Kruijssen
COOL Research DAO
Technische Universität München
Elizabeth Mills
University of Kansas
Maya Petkova
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
Mattia C. Sormani
University of Surrey
Universita degli Studi dell'Insubria
Jen Wallace
University of Connecticut
Jairo Armijos-Abendano
Escuela Politécnica Nacional
Katarzyna M. Dutkowska
Universiteit Leiden
Rei Enokiya
Nagoya University
Yasuo Fukui
Nagoya University
Pablo Garcia
Chinese Academy of Sciences
Universidad Catolica del Norte
Andres Guzman
Atacama Large Millimeter-submillimeter Array (ALMA)
Christian Henkel
Max-Planck-Gesellschaft
Pei-Ying Hsieh
National Astronomical Observatory of Japan
Yue Hu
Princeton University
Katharina Immer
European Southern Observatory (ESO)
Desmond Jeff
University of Florida
National Radio Astronomy Observatory
Ralf S. Klessen
Universität Heidelberg
Harvard-Smithsonian Center for Astrophysics
Harvard University
Kotaro Kohno
University of Tokyo
Mark R. Krumholz
Australian National University
Dani Lipman
University of Connecticut
Mark R. Morris
University of California
Francisco Nogueras-Lara
European Southern Observatory (ESO)
M. Nonhebel
University of St Andrews
European Southern Observatory (ESO)
Jurgen Ott
National Radio Astronomy Observatory Socorro
Jaime E. Pineda
MPI fur Extraterrestrische Physik
Sergio Martin
Atacama Large Millimeter-submillimeter Array (ALMA)
European Southern Observatory Santiago
Miguel Angel Requena-Torres
Towson University
Victor M. Rivilla
Consejo Superior de Investigaciones Científicas (CSIC)
Denise Riquelme-Vasquez
Universidad de La Serena
Alvaro Sanchez-Monge
Consejo Superior de Investigaciones Científicas (CSIC)
Inst Estudis Espacials Catalunya IEEC
Miriam G. Santa-Maria
University of Florida
Howard A. Smith
Harvard-Smithsonian Center for Astrophysics
Tabassum S. Tanvir
Iowa State University
Volker Tolls
Harvard-Smithsonian Center for Astrophysics
Q. Daniel Wang
University of Massachusetts
Publication of the Astronomical Society of Japan
0004-6264 (ISSN) 2053051x (eISSN)
Vol. In PressÄmneskategorier (SSIF 2025)
Strömningsmekanik
Astronomi, astrofysik och kosmologi
DOI
10.1093/pasj/psaf034