GMVA20B-269

Sharpening the Source Model for Sgr A* with GMVA+ALMA

Abstract

While black holes are ubiquitous, our understanding of how strong gravity and energetic material interact to produce the light we observe from them remains limited. The Galactic Center supermassive black hole, Sagittarius A* (Sgr A*), is the most promising target to study the dynamics of black hole accretion and outflow via direct imaging. At 3.5-mm, the emission from Sgr A* originates within ~12 Schwarzschild radii of the black hole and is resolvable with the GMVA. Results from our Cycle 4 (2017) observations enabled the first imaging of Sgr A* at 3.5-mm, revealing a nearly isotropic intrinsic source. This image constrained a representative set of emission models to disks or low-inclination jets. In addition, long-baseline detections to ALMA in Cycles 4-5 confirmed that scattering effects will not dominate images of Sgr A* with the Event Horizon Telescope. For Cycle 8, we request a full-polarization GMVA+ALMA imaging observation of Sgr A* at 3.5-mm, adding the highly sensitive LMT and doubling the bandwidth. These observations will test the persistence of the compact intrinsic structure, and they will have the sensitivity to track and characterize intra-hour variability, providing critical insights into the source and emission models for Sgr A*.

Investigators

Name	Institution
Hector Olivares	Nijmegen, Radboud Universiteit
Wu Jiang	Shanghai Astronomical Observatory, CAS
zhi-qiang shen	Shanghai Astronomical Observatory, CAS
Ramesh Karuppusamy	Max-Planck-Institut für Radioastronomie
Ue-Li Pen	Toronto, University of
Venkatessh Ramakrishnan	Turku, University of
Elisabetta Liuzzo	Istituto Nazionale di Astrofisica
Kazi Rygl	Istituto Nazionale di Astrofisica
Jordy Davelaar	Columbia University
Yosuke Mizuno	Shanghai Jiao Tong University; Frankfurt am Main, Goethe-Universität
Tomohisa Kawashima	Tokyo, University of
David James	Smithsonian Astrophysical Observatory
Dominic Pesce	Virginia, University of; Smithsonian Astrophysical Observatory
Jae-Young Kim	Max-Planck-Institut für Radioastronomie; Kyungpook National University
Gunther Witzel	California at Los Angeles, University of; Max-Planck-Institut für Radioastronomie
Yurii Pidopryhora	Max-Planck-Institut für Radioastronomie
Jan Wagner	Max-Planck-Institut für Radioastronomie
Helge Rottmann	Max-Planck-Institut für Radioastronomie
Scott Ransom	National Radio Astronomy Observatory; Virginia, University of
Shami Chatterjee	Cornell University
John Wardle	Brandeis University
Jim Cordes	Cornell University
Robert Wharton	Jet Propulsion Laboratory
Gregory Desvignes	Max-Planck-Institut für Radioastronomie; Paris, Observatoire de
Kuo Liu	Max-Planck-Institut für Radioastronomie
Michael Kramer	Manchester, University of; Max-Planck-Institut für Radioastronomie
Luciano Rezzolla	Frankfurt am Main, Goethe-Universität
Jose L. Gomez	Andalucía, Instituto de Astrofísica de
Jim Moran	Harvard University; Center for Astrophysics | Harvard & Smithsonian
Andrew Chael	Princeton University
Raquel Fraga-Encinas	Nijmegen, Radboud Universiteit
Roman Gold	Maryland, University of; Perimeter Institute for Theoretical Physics; Syddansk Universitet
Avery Broderick	Waterloo, University of
Feryal Ozel	Arizona, University of
Dimitrios Psaltis	Arizona, University of
Keiichi Asada	Academia Sinica
Tony Zensus	National Radio Astronomy Observatory; Max-Planck-Institut für Radioastronomie
Remo Tilanus	Arizona, University of
Kazuhiro Hada	Istituto Nazionale di Astrofisica; National Astronomical Observatory of Japan
David Sanchez-Arguelles	Astrofísica, Óptica y Electrónica, Instituto Nacional de
Antonio Hernandez	Max-Planck-Institut für Radioastronomie
Laurent Loinard	México, Universidad Nacional Autónoma de
Gopal Narayanan	Massachusetts at Amherst, University of
David Hughes	Astrofísica, Óptica y Electrónica, Instituto Nacional de
Silke Britzen	Max-Planck-Institut für Radioastronomie
Motoki Kino	National Astronomical Observatory of Japan ; Korea Astronomy and Space Science Institute
Ilje Cho	Korea Astronomy and Space Science Institute; Andalucía, Instituto de Astrofísica de; Korea University of Science and Technology
Guangyao Zhao	Max-Planck-Institut für Radioastronomie; Korea Astronomy and Space Science Institute; Andalucía, Instituto de Astrofísica de
Rusen Lu	Max-Planck-Institut für Radioastronomie; Shanghai Astronomical Observatory, CAS
Katherine Bouman	Massachusetts Institute of Technology; California Institute of Technology
Kazunori Akiyama	Massachusetts Institute of Technology; Haystack Observatory
Jason Dexter	Colorado at Boulder, University of
Dan Marrone	Arizona, University of
Geoffrey Bower	Academia Sinica
Heino Falcke	Netherlands Institute for Radio Astronomy; Nijmegen, Radboud Universiteit
Eduardo Ros	Max-Planck-Institut für Radioastronomie; València, Universitat de
Vincent Fish	Haystack Observatory
Freek Roelofs	Center for Astrophysics | Harvard & Smithsonian; Nijmegen, Radboud Universiteit
Michael Janssen	Max-Planck-Institut für Radioastronomie; Nijmegen, Radboud Universiteit
Shep Doeleman	Haystack Observatory
Sera Markoff	Amsterdam, Universiteit van
Monika Moscibrodzka	Nijmegen, Radboud Universiteit
Thomas Krichbaum	Max-Planck-Institut für Radioastronomie
Ciriaco Goddi	Center for Astrophysics | Harvard & Smithsonian; European Southern Observatory; Joint Institute for Very Long Baseline Interferometry European Research Infrastructure Consortium; Nijmegen, Radboud Universiteit
Maciek Wielgus	Max-Planck-Institut für Radioastronomie; Smithsonian Astrophysical Observatory
Christiaan Brinkerink	Nijmegen, Radboud Universiteit
Michael Johnson	California at Santa Barbara, University of; Center for Astrophysics | Harvard & Smithsonian
Lindy Blackburn	Center for Astrophysics | Harvard & Smithsonian
Sara Issaoun *	Center for Astrophysics | Harvard & Smithsonian; Nijmegen, Radboud Universiteit
GBT Operator	Green Bank Observatory

* indicates the PI