GMVA22B-249

Resolving Polarization in 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 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. Cycle 4 (2017) results revealed a nearly isotropic intrinsic source with an angular size of ~12 Schwarzschild radii. This image constrained a set of emission models to disks or low-inclination jets. Long-baseline detections to ALMA in Cycles 4-5 (2017-2018) also confirmed that scattering effects will not dominate 1.3-mm VLBI images of Sgr A*. Cycle 8 (2022), with LMT participation and doubling of the bandwidth, will improve total-intensity imaging of the intrinsic structure. For Cycle 9 (2023), we request a full-polarization GMVA+ALMA imaging observation of Sgr A* at 3.5-mm, with a high-bandwidth polarization-focused sub-array. The VLBA and GBT will provide key calibration and imaging input while we leverage the high-bandwidth capabilities of (sub)millimeter GMVA and guest facilities to detect polarization structure in Sgr A* on VLBI scales at 3.5-mm for the first time, providing critical insight into the accretion flow configuration of Sgr A*.

Investigators

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

* indicates the PI