The Astrophysical Journal Letters (Jan 2024)
A Broad Line-width, Compact, Millimeter-bright Molecular Emission Line Source near the Galactic Center
- Adam Ginsburg,
- John Bally,
- Ashley T. Barnes,
- Cara Battersby,
- Nazar Budaiev,
- Natalie O. Butterfield,
- Paola Caselli,
- Laura Colzi,
- Katarzyna M. Dutkowska,
- Pablo García,
- Savannah Gramze,
- Jonathan D. Henshaw,
- Yue Hu,
- Desmond Jeff,
- Izaskun Jiménez-Serra,
- Jens Kauffmann,
- Ralf S. Klessen,
- Emily M. Levesque,
- Steven N. Longmore,
- Xing Lu,
- Elisabeth A. C. Mills,
- Mark R. Morris,
- Francisco Nogueras-Lara,
- Tomoharu Oka,
- Jaime E. Pineda,
- Thushara G. S. Pillai,
- Víctor M. Rivilla,
- Álvaro Sánchez-Monge,
- Miriam G. Santa-Maria,
- Howard A. Smith,
- Yoshiaki Sofue,
- Mattia C. Sormani,
- Grant R. Tremblay,
- Gijs Vermariën,
- Alexey Vikhlinin,
- Serena Viti,
- Dan Walker,
- Q. Daniel Wang,
- Fengwei Xu,
- Qizhou Zhang
Affiliations
- Adam Ginsburg
- ORCiD
- Department of Astronomy, University of Florida , P.O. Box 112055, Gainesville, FL 32611, USA
- John Bally
- ORCiD
- Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado , Boulder, CO 80389, USA
- Ashley T. Barnes
- ORCiD
- European Southern Observatory (ESO) , Karl-Schwarzschild-Straße 2, 85748 Garching, Germany
- Cara Battersby
- ORCiD
- Department of Physics, University of Connecticut , 196A Auditorium Road, Unit 3046, Storrs, CT 06269, USA
- Nazar Budaiev
- ORCiD
- Department of Astronomy, University of Florida , P.O. Box 112055, Gainesville, FL 32611, USA
- Natalie O. Butterfield
- ORCiD
- National Radio Astronomy Observatory , 520 Edgemont Road, Charlottesville, VA 22903, USA
- Paola Caselli
- ORCiD
- Max-Planck-Institut für extraterrestrische Physik , Giessenbachstrasse 1, D-85748 Garching, Germany
- Laura Colzi
- ORCiD
- Centro de Astrobiología (CAB) , CSIC-INTA, Carretera de Ajalvir km 4, Torrejón de Ardoz, 28850 Madrid, Spain
- Katarzyna M. Dutkowska
- ORCiD
- Leiden Observatory, Leiden University , P.O. Box 9513, 2300 RA Leiden, The Netherlands
- Pablo García
- ORCiD
- Instituto de Astronomía, Universidad Católica del Norte , Av. Angamos 0610, Antofagasta, Chile; Chinese Academy of Sciences South America Center for Astronomy , National Astronomical Observatories, CAS, Beijing 100101, People's Republic of China
- Savannah Gramze
- ORCiD
- Department of Astronomy, University of Florida , P.O. Box 112055, Gainesville, FL 32611, USA
- Jonathan D. Henshaw
- ORCiD
- Astrophysics Research Institute, Liverpool John Moores University , IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF, UK; Max Planck Institute for Astronomy , Königstuhl 17, D-69117 Heidelberg, Germany
- Yue Hu
- ORCiD
- Department of Physics, University of Wisconsin–Madison , Madison, WI, 53706, USA
- Desmond Jeff
- ORCiD
- Department of Astronomy, University of Florida , P.O. Box 112055, Gainesville, FL 32611, USA; National Radio Astronomy Observatory , 520 Edgemont Road, Charlottesville, VA 22903-2475, USA
- Izaskun Jiménez-Serra
- ORCiD
- Centro de Astrobiología (CAB) , CSIC-INTA, Carretera de Ajalvir km 4, Torrejón de Ardoz, 28850 Madrid, Spain
- Jens Kauffmann
- ORCiD
- Haystack Observatory, Massachusetts Institute of Technology , 99 Milsstone Road, Westford, MA 01886, USA
- Ralf S. Klessen
- ORCiD
- Universität Heidelberg, Zentrum für Astronomie, Institut für Theoretische Astrophysik , Albert-Ueberle-Str. 2, 69120 Heidelberg, Germany; Universität Heidelberg , Interdisziplinäres Zentrum für Wissenschaftliches Rechnen, Im Neuenheimer Feld 205, 69120 Heidelberg, Germany
- Emily M. Levesque
- ORCiD
- Department of Astronomy, Box 351580, University of Washington , Seattle, WA 98195, USA
- Steven N. Longmore
- ORCiD
- Astrophysics Research Institute, Liverpool John Moores University , IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF, UK; COOL Research DAO , Germany
- Xing Lu
- ORCiD
- Shanghai Astronomical Observatory, Chinese Academy of Sciences , 80 Nandan Road, Shanghai 200030, People’s Republic of China
- Elisabeth A. C. Mills
- ORCiD
- Department of Physics and Astronomy, University of Kansas , 1251 Wescoe Hall Drive, Lawrence, KS 66045, USA
- Mark R. Morris
- ORCiD
- Department of Physics & Astronomy, University of California , Los Angeles, Los Angeles, CA 90095-1547, USA
- Francisco Nogueras-Lara
- ORCiD
- European Southern Observatory , Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany
- Tomoharu Oka
- ORCiD
- Department of Physics, Faculy of Science and Technology, Keio University , 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
- Jaime E. Pineda
- ORCiD
- Max-Planck-Institut für extraterrestrische Physik , Giessenbachstrasse 1, D-85748 Garching, Germany
- Thushara G. S. Pillai
- ORCiD
- Haystack Observatory, Massachusetts Institute of Technology , 99 Milsstone Road, Westford, MA 01886, USA
- Víctor M. Rivilla
- ORCiD
- Centro de Astrobiología (CAB) , CSIC-INTA, Carretera de Ajalvir km 4, Torrejón de Ardoz, 28850 Madrid, Spain
- Álvaro Sánchez-Monge
- ORCiD
- Institute of Space Sciences (ICE, CSIC) , Campus UAB, Carrer de Can Magrans s/n, 08193, Bellaterra (Barcelona), Spain; Institute of Space Studies of Catalonia (IEEC) , 08860, Barcelona, Spain
- Miriam G. Santa-Maria
- ORCiD
- Department of Astronomy, University of Florida , P.O. Box 112055, Gainesville, FL 32611, USA
- Howard A. Smith
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA
- Yoshiaki Sofue
- Institue of Astronomy, The University of Tokyo , Mitaka, Tokyo, 181-0015, Japan
- Mattia C. Sormani
- ORCiD
- Department of Physics, University of Surrey , Guildford GU2 7XH, UK; Università dell’Insubria , via Valleggio 11, 22100 Como, Italy
- Grant R. Tremblay
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA
- Gijs Vermariën
- ORCiD
- Leiden Observatory, Leiden University , P.O. Box 9513, 2300 RA Leiden, The Netherlands
- Alexey Vikhlinin
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA
- Serena Viti
- ORCiD
- Leiden Observatory, Leiden University , P.O. Box 9513, 2300 RA Leiden, The Netherlands
- Dan Walker
- Department of Astronomy, University of Massachusetts , Amherst, MA 01003, USA
- Q. Daniel Wang
- ORCiD
- Department of Astronomy, University of Massachusetts , Amherst, MA 01003, USA
- Fengwei Xu
- ORCiD
- Kavli Institute for Astronomy and Astrophysics, Peking University , Beijing 100871, People’s Republic of China; Department of Astronomy, School of Physics, Peking University , Beijing, 100871, People’s Republic of China
- Qizhou Zhang
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA
- DOI
- https://doi.org/10.3847/2041-8213/ad47fa
- Journal volume & issue
-
Vol. 968,
no. 1
p. L11
Abstract
A compact source, G0.02467–0.0727, was detected in Atacama Large Millimeter/submillimeter Array 3 mm observations in continuum and very broad line emission. The continuum emission has a spectral index α ≈ 3.3, suggesting that the emission is from dust. The line emission is detected in several transitions of CS, SO, and SO _2 and exhibits a line width FWHM ≈ 160 km s ^−1 . The line profile appears Gaussian. The emission is weakly spatially resolved, coming from an area on the sky ≲1″ in diameter (≲10 ^4 au at the distance of the Galactic center, GC). The centroid velocity is v _LSR ≈ 40–50 km s ^−1 , which is consistent with a location in the GC. With multiple SO lines detected, and assuming local thermodynamic equilibrium (LTE) conditions, the gas temperature is T _LTE = 13 K, which is colder than seen in typical GC clouds, though we cannot rule out low-density, subthermally excited, warmer gas. Despite the high velocity dispersion, no emission is observed from SiO, suggesting that there are no strong (≳10 km s ^−1 ) shocks in the molecular gas. There are no detections at other wavelengths, including X-ray, infrared, and radio. We consider several explanations for the millimeter ultra-broad-line object (MUBLO), including protostellar outflow, explosive outflow, a collapsing cloud, an evolved star, a stellar merger, a high-velocity compact cloud, an intermediate-mass black hole, and a background galaxy. Most of these conceptual models are either inconsistent with the data or do not fully explain them. The MUBLO is, at present, an observationally unique object.
Keywords
