Disruption of a massive molecular cloud by a supernova in the Galactic Centre

Initial results from the ACES project

¹ European Southern Observatory (ESO), Karl-Schwarzschild-Straße 2, 85748 Garching, Germany
² SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, UK
³ School of Physics and Astronomy, Cardiff University, The Parade, Cardiff CF24 3AA, UK
⁴ Observatorio Astronómico de Quito, Escuela Politécnica Nacional, Interior del Parque La Alameda, 170136 Quito, Ecuador
⁵ Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80389, USA
⁶ University of Connecticut, Department of Physics, 196A Hillside Road, Unit 3046 Storrs, CT 06269-3046, USA
⁷ Armagh Observatory and Planetarium, College Hill, Armagh BT61 9DB, Northern Ireland
⁸ National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903, USA
⁹ Centro de Astrobiología (CAB), CSIC-INTA, Carretera de Ajalvir km 4, Torrejón de Ardoz, 28850 Madrid, Spain
¹⁰ Instituto de Astronomía, Universidad Católica del Norte, Av. Angamos 0610, Antofagasta, Chile
¹¹ Chinese Academy of Sciences South America Center for Astronomy, National Astronomical Observatories, CAS, Beijing 100101, China
¹² Department of Astronomy, University of Florida, PO Box 112055, Gainesville, FL 32611, USA
¹³ Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF, UK
¹⁴ Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
¹⁵ Institute for Advanced Study, 1 Einstein Drive, Princeton, NJ 08540, USA
¹⁶ Universität Heidelberg, Zentrum für Astronomie, Institut für Theoretische Astrophysik, Albert-Ueberle-Straße 2, 69120 Heidelberg, Germany
¹⁷ Universität Heidelberg, Interdisziplinäres Zentrum für Wissenschaftliches Rechnen, Im Neuenheimer Feld 205, 69120 Heidelberg, Germany
¹⁸ Technical University of Munich, School of Engineering and Design, Department of Aerospace and Geodesy, Chair of Remote Sensing Technology, Arcisstr. 21, 80333 Munich, Germany
¹⁹ Cosmic Origins Of Life (COOL) Research DAO, https://coolresearch.io,
²⁰ Sub-department of Astrophysics, Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK
²¹ Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, China
²² European Southern Observatory, Alonso de Córdova, 3107, Vitacura, Santiago 763-0355, Chile
²³ Joint ALMA Observatory, Alonso de Córdova, 3107, Vitacura, Santiago 763-0355, Chile
²⁴ Department of Physics and Astronomy, University of Kansas, 1251 Wescoe Hall Drive, Lawrence, KS 66045, USA
²⁵ Department of Space, Earth & Environment, Chalmers University of Technology, 412 96 Gothenburg, Sweden
²⁶ Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, 85748 Garching, Germany
²⁷ Institut de Ciències de l’Espai (ICE, CSIC), Campus UAB, Carrer de Can Magrans s/n, 08193 Bellaterra (Barcelona), Spain
²⁸ Institut d’Estudis Espacials de Catalunya (IEEC), 08860 Castelldefels (Barcelona), Spain
²⁹ Center for Astrophysics Harvard and Smithsonian, Cambridge, MA 02138, USA
³⁰ Institute of Astronomy, The University of Tokyo, Mitaka, Tokyo 181-0015, Japan
³¹ Università dell’Insubria, via Valleggio 11, 22100 Como, Italy
³² UK ALMA Regional Centre Node, Jodrell Bank Centre for Astrophysics, The University of Manchester, Manchester M13 9PL, UK
³³ Department of Astronomy, University of Massachusetts, Amherst, MA 01003, USA
³⁴ Department of Physics, Aberystwyth University, Ceredigion, Cymru SY23 3BZ, UK
³⁵ I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
³⁶ Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, PR China
³⁷ Department of Astronomy, School of Physics, Peking University, Beijing, 100871, PR China

^★ Corresponding author; mn92@st-andrews.ac.uk

Received: 20 June 2024
Accepted: 11 September 2024

Abstract

The Milky Way’s Central Molecular Zone (CMZ) differs dramatically from our local solar neighbourhood, both in the extreme interstellar medium conditions it exhibits (e.g. high gas, stellar, and feedback density) and in the strong dynamics at play (e.g. due to shear and gas influx along the bar). Consequently, it is likely that there are large-scale physical structures within the CMZ that cannot form elsewhere in the Milky Way. In this paper, we present new results from the Atacama Large Millimeter/submillimeter Array (ALMA) large programme ACES (ALMA CMZ Exploration Survey) and conduct a multi-wavelength and kinematic analysis to determine the origin of the M0.8–0.2 ring, a molecular cloud with a distinct ring-like morphology. We estimate the projected inner and outer radii of the M0.8–0.2 ring to be 79″ and 154″, respectively (3.1 pc and 6.1 pc at an assumed Galactic Centre distance of 8.2 kpc) and calculate a mean gas density >10⁴ cm⁻³, a mass of ~10⁶ M_⊙, and an expansion speed of ~20 km s⁻¹, resulting in a high estimated kinetic energy (>10⁵¹ erg) and momentum (>10⁷ M_⊙ km s⁻¹). We discuss several possible causes for the existence and expansion of the structure, including stellar feedback and large-scale dynamics. We propose that the most likely cause of the M0.8–0.2 ring is a single high-energy hypernova explosion. To viably explain the observed morphology and kinematics, such an explosion would need to have taken place inside a dense, very massive molecular cloud, the remnants of which we now see as the M0.8–0.2 ring. In this case, the structure provides an extreme example of how supernovae can affect molecular clouds.