Rotation and stability of the circumnuclear gas disk in the Galactic Center potential by the ALMA CMZ Exploration Survey (ACES)

Sofue, Y ORCID: 0000-0002-4268-6499, Longmore, SN ORCID: 0000-0001-6353-0170, Walker, D ORCID: 0000-0001-7330-8856, Ginsburg, A, Henshaw, JD ORCID: 0000-0001-9656-7682, Bally, J, Barnes, AT ORCID: 0000-0003-0410-4504, Battersby, C, Colzi, L, Ho, P, Jimenez-Serra, I, Kruijssen, JMD ORCID: 0000-0002-8804-0212, Mills, E, Petkova, MA, Sormani, MC, Wallace, J, Armijos-Abendaño, J, Feng, ZX, Fiteni, K ORCID: 0000-0002-9409-8322, García, P et al (2026) Rotation and stability of the circumnuclear gas disk in the Galactic Center potential by the ALMA CMZ Exploration Survey (ACES). Publications of the Astronomical Society of Japan, 78 (2). pp. 536-555. ISSN 0004-6264

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Abstract

We investigated the gravitational potential and mass distribution in the Galactic Center by examining the morphology and kinematics of the circumnuclear gaseous disk revealed by the molecular line data from the ALMA CMZ Exploration Survey. We obtain an estimate of the shape of the potential within the central ∼20pc to reproduce the observed properties of the circumnuclear gas disk by simulating the motion of test particles for various axial ratios and show that the potential is approximately spherical. We construct a rotation curve by applying the terminal velocity method to the position–velocity diagrams, and calculate the mass distribution in the Galactic Center. The distribution of mass density is found to be of cusp type, approximated by ρdyn ∼ 1 . 56 ×105 (R / 1pc )−1 . 9 M⊙ pc −3 where R is the distance from the nucleus. We discuss the tidal effect caused by the gravitational potential that produces the rotation curve and show that the gas disk is stable against self-gravitational contraction within a critical radius of RT ∼ 14 (ρgas / 105 H2 cm −3 )−1 / 2 pc . This suggests suppression of star formation and a top-heavy initial mass function in the circumnuclear region.

Item Type:	Article
Uncontrolled Keywords:	Galaxy: center; Galaxy: structure; ISM: clouds; ISM: kinematics and dynamics; stars: formation; 5109 Space Sciences; 51 Physical Sciences; 0201 Astronomical and Space Sciences; Astronomy & Astrophysics; 5101 Astronomical sciences
Subjects:	Q Science > QB Astronomy
Divisions:	Astrophysics Research Institute
Publisher:	Oxford University Press
Date of acceptance:	26 December 2025
Date of first compliant Open Access:	12 June 2026
Date Deposited:	12 Jun 2026 12:31
Last Modified:	12 Jun 2026 12:31
DOI or ID number:	10.1093/pasj/psaf159
URI:	https://researchonline.ljmu.ac.uk/id/eprint/28823

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