Persistent Non-Gaussian Structure in the Image of Sagittarius A∗ at 86 GHz

Issaoun, Sara; Johnson, M. D.; Blackburn, Lindy; Broderick, Avery E.; Tiede, Paul; Wielgus, Maciek; Doeleman, Sheperd S.; Falcke, H.; Akiyama, K.; Bower, G. C.; Brinkerink, C. D.; Chael, A.; Cho, I.; Gómez Fernández, José L.; Hernández-Gómez, A.; Hughes, D.; Kino, Motoki; Krichbaum, Thomas P.; Liuzzo, Elisabetta; Loinard, Laurent; Markoff, S.; Marrone, Daniel P.; Mizuno, Y.; Morán, J. M.; Pidopryhora, Y.; Ros, E.; Rygl, K.; Shen, Zhi-Qiang; Wagner, J.

Persistent Non-Gaussian Structure in the Image of Sagittarius A∗ at 86 GHz

Observations of the Galactic Center supermassive black hole Sagittarius A∗ (Sgr A∗) with very long-baseline interferometry (VLBI) are affected by interstellar scattering along our line of sight. At long radio observing wavelengths (≲1 cm), the scattering heavily dominates image morphology. At 3.5 mm...

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Authors:	Issaoun, Sara, Johnson, M. D., Blackburn, Lindy, Broderick, Avery E., Tiede, Paul, Wielgus, Maciek, Doeleman, Sheperd S., Falcke, H., Akiyama, K., Bower, G. C., Brinkerink, C. D., Chael, A., Cho, I., Gómez Fernández, José L., Hernández-Gómez, A., Hughes, D., Kino, Motoki, Krichbaum, Thomas P., Liuzzo, Elisabetta, Loinard, Laurent, Markoff, S., Marrone, Daniel P., Mizuno, Y., Morán, J. M., Pidopryhora, Y., Ros, E., Rygl, K., Shen, Zhi-Qiang, Wagner, J.
Format:	article
Status:	Versión aceptada para publicación
Publication Date:	2021
Country:	España
Institution:	Consejo Superior de Investigaciones Científicas (CSIC)
Repository:	DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:	oai:digital.csic.es:10261/256621
Online Access:	http://hdl.handle.net/10261/256621
Access Level:	Open access
Keyword:	Black holes Galaxies: individual: Sgr A* Galaxy: center Techniques: interferometric

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network_acronym_str	ES
network_name_str	España
repository_id_str
dc.title.none.fl_str_mv	Persistent Non-Gaussian Structure in the Image of Sagittarius A∗ at 86 GHz
title	Persistent Non-Gaussian Structure in the Image of Sagittarius A∗ at 86 GHz
spellingShingle	Persistent Non-Gaussian Structure in the Image of Sagittarius A∗ at 86 GHz Issaoun, Sara Black holes Galaxies: individual: Sgr A* Galaxy: center Techniques: interferometric
title_short	Persistent Non-Gaussian Structure in the Image of Sagittarius A∗ at 86 GHz
title_full	Persistent Non-Gaussian Structure in the Image of Sagittarius A∗ at 86 GHz
title_fullStr	Persistent Non-Gaussian Structure in the Image of Sagittarius A∗ at 86 GHz
title_full_unstemmed	Persistent Non-Gaussian Structure in the Image of Sagittarius A∗ at 86 GHz
title_sort	Persistent Non-Gaussian Structure in the Image of Sagittarius A∗ at 86 GHz
dc.creator.none.fl_str_mv	Issaoun, Sara Johnson, M. D. Blackburn, Lindy Broderick, Avery E. Tiede, Paul Wielgus, Maciek Doeleman, Sheperd S. Falcke, H. Akiyama, K. Bower, G. C. Brinkerink, C. D. Chael, A. Cho, I. Gómez Fernández, José L. Hernández-Gómez, A. Hughes, D. Kino, Motoki Krichbaum, Thomas P. Liuzzo, Elisabetta Loinard, Laurent Markoff, S. Marrone, Daniel P. Mizuno, Y. Morán, J. M. Pidopryhora, Y. Ros, E. Rygl, K. Shen, Zhi-Qiang Wagner, J.
author	Issaoun, Sara
author_facet	Issaoun, Sara Johnson, M. D. Blackburn, Lindy Broderick, Avery E. Tiede, Paul Wielgus, Maciek Doeleman, Sheperd S. Falcke, H. Akiyama, K. Bower, G. C. Brinkerink, C. D. Chael, A. Cho, I. Gómez Fernández, José L. Hernández-Gómez, A. Hughes, D. Kino, Motoki Krichbaum, Thomas P. Liuzzo, Elisabetta Loinard, Laurent Markoff, S. Marrone, Daniel P. Mizuno, Y. Morán, J. M. Pidopryhora, Y. Ros, E. Rygl, K. Shen, Zhi-Qiang Wagner, J.
author_role	author
author2	Johnson, M. D. Blackburn, Lindy Broderick, Avery E. Tiede, Paul Wielgus, Maciek Doeleman, Sheperd S. Falcke, H. Akiyama, K. Bower, G. C. Brinkerink, C. D. Chael, A. Cho, I. Gómez Fernández, José L. Hernández-Gómez, A. Hughes, D. Kino, Motoki Krichbaum, Thomas P. Liuzzo, Elisabetta Loinard, Laurent Markoff, S. Marrone, Daniel P. Mizuno, Y. Morán, J. M. Pidopryhora, Y. Ros, E. Rygl, K. Shen, Zhi-Qiang Wagner, J.
author2_role	author author author author author author author author author author author author author author author author author author author author author author author author author author author author
dc.contributor.none.fl_str_mv	European Research Council European Commission National Science Foundation (US) Gordon and Betty Moore Foundation Universidad Nacional Autónoma de México Consejo Nacional de Ciencia y Tecnología (México) Ministerio de Economía y Competitividad (España) Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv	Black holes Galaxies: individual: Sgr A* Galaxy: center Techniques: interferometric
topic	Black holes Galaxies: individual: Sgr A* Galaxy: center Techniques: interferometric
description	Observations of the Galactic Center supermassive black hole Sagittarius A∗ (Sgr A∗) with very long-baseline interferometry (VLBI) are affected by interstellar scattering along our line of sight. At long radio observing wavelengths (≲1 cm), the scattering heavily dominates image morphology. At 3.5 mm (86 GHz), the intrinsic source structure is no longer sub-dominant to scattering, and thus the intrinsic emission from Sgr A∗ is resolvable with the Global Millimeter VLBI Array (GMVA). Long-baseline detections to the phased Atacama Large Millimeter/submillimeter Array (ALMA) in 2017 provided new constraints on the intrinsic and scattering properties of Sgr A∗, but the stochastic nature of the scattering Requires multiple observing epochs to reliably estimate its statistical properties. We present new observations with the GMVA+ALMA, taken in 2018, which confirm non-Gaussian structure in the scattered image seen in 2017. In particular, the ALMA-GBT baseline shows more flux density than expected for an anistropic Gaussian model, providing a tight constraint on the source size and an upper limit on the dissipation scale of interstellar turbulence. We find an intrinsic source extent along the minor axis of ∼100 μas both via extrapolation of longer wavelength scattering constraints and direct modeling of the 3.5 mm observations. Simultaneously fitting for the scattering parameters, we find an at-most modestly asymmetrical (major-to-minor axis ratio of 1.5 0.2) intrinsic source morphology for Sgr A∗. © 2021. The American Astronomical Society. All rights reserved.
publishDate	2021
dc.date.none.fl_str_mv	2021 2021 2021
dc.type.none.fl_str_mv	info:eu-repo/semantics/article http://purl.org/coar/resource_type/c_6501 Postprint info:eu-repo/semantics/acceptedVersion
format	article
status_str	acceptedVersion
dc.identifier.none.fl_str_mv	http://hdl.handle.net/10261/256621
url	http://hdl.handle.net/10261/256621
dc.language.none.fl_str_mv	Inglés
language_invalid_str_mv	Inglés
dc.relation.none.fl_str_mv	#PLACEHOLDER_PARENT_METADATA_VALUE# #PLACEHOLDER_PARENT_METADATA_VALUE# info:eu-repo/grantAgreement/EC/H2020/610058 info:eu-repo/grantAgreement/MINECO/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/SEV-2017-0709 http://dx.doi.org/10.3847/1538-4357/ac00b0 Sí
dc.rights.none.fl_str_mv	info:eu-repo/semantics/openAccess
eu_rights_str_mv	openAccess
dc.publisher.none.fl_str_mv	IOP Publishing
publisher.none.fl_str_mv	IOP Publishing
dc.source.none.fl_str_mv	reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str	Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str	DIGITAL.CSIC. Repositorio Institucional del CSIC
collection	DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
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spelling	Persistent Non-Gaussian Structure in the Image of Sagittarius A∗ at 86 GHzIssaoun, SaraJohnson, M. D.Blackburn, LindyBroderick, Avery E.Tiede, PaulWielgus, MaciekDoeleman, Sheperd S.Falcke, H.Akiyama, K.Bower, G. C.Brinkerink, C. D.Chael, A.Cho, I.Gómez Fernández, José L.Hernández-Gómez, A.Hughes, D.Kino, MotokiKrichbaum, Thomas P.Liuzzo, ElisabettaLoinard, LaurentMarkoff, S.Marrone, Daniel P.Mizuno, Y.Morán, J. M.Pidopryhora, Y.Ros, E.Rygl, K.Shen, Zhi-QiangWagner, J.Black holesGalaxies: individual: Sgr A*Galaxy: centerTechniques: interferometricObservations of the Galactic Center supermassive black hole Sagittarius A∗ (Sgr A∗) with very long-baseline interferometry (VLBI) are affected by interstellar scattering along our line of sight. At long radio observing wavelengths (≲1 cm), the scattering heavily dominates image morphology. At 3.5 mm (86 GHz), the intrinsic source structure is no longer sub-dominant to scattering, and thus the intrinsic emission from Sgr A∗ is resolvable with the Global Millimeter VLBI Array (GMVA). Long-baseline detections to the phased Atacama Large Millimeter/submillimeter Array (ALMA) in 2017 provided new constraints on the intrinsic and scattering properties of Sgr A∗, but the stochastic nature of the scattering Requires multiple observing epochs to reliably estimate its statistical properties. We present new observations with the GMVA+ALMA, taken in 2018, which confirm non-Gaussian structure in the scattered image seen in 2017. In particular, the ALMA-GBT baseline shows more flux density than expected for an anistropic Gaussian model, providing a tight constraint on the source size and an upper limit on the dissipation scale of interstellar turbulence. We find an intrinsic source extent along the minor axis of ∼100 μas both via extrapolation of longer wavelength scattering constraints and direct modeling of the 3.5 mm observations. Simultaneously fitting for the scattering parameters, we find an at-most modestly asymmetrical (major-to-minor axis ratio of 1.5 0.2) intrinsic source morphology for Sgr A∗. © 2021. The American Astronomical Society. All rights reserved.This work is supported by the ERC Synergy grant "BlackHoleCam: Imaging the Event Horizon of Black Holes", grant 610058. We thank the National Science Foundation (AST-1716536, AST-1440254, AST-1935980, AST-2034306) and the Gordon and Betty Moore Foundation (GBMF-5278) for financial support of this work. This work was supported in part by the black hole Initiative, which is funded by grants from the John Templeton Foundation and the Gordon and Betty Moore Foundation to Harvard University. A.C. is supported by Hubble Fellowship grant HST-HF2-51431.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. I.C. is supported by the National Research Foundation of Korea (NRF) via a Global PhD Fellowship grant (NRF-2015H1A2A1033752). L.L. acknowledges the financial support of DGAPA, UNAM (projects IN112417 and IN112820), and CONACyT, Mexico (projects 275201-Agencia Espacial Mexicana; and 263356-Ciencia de Frontera). M.K. was supported by JSPS KAKENHI grant Nos. JP18K03656 and JP18H03721. This paper makes use of the following ALMA data: ADS/JAO.ALMA2017.1.00795.V. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. The ALMA data required non-standard processing by the VLBI QA2 team (C. Goddi, I. Marti-Vidal, G. B. Crew, H. Rottmann, and H. Messias). This research has made use of data obtained with the Global Millimeter VLBI Array (GMVA), coordinated by the VLBI group at the Max-Planck-Institut fur Radioastronomie (MPIfR). The GMVA consists of telescopes operated by MPIfR, IRAM, Onsala, Metsahovi, Yebes, the Korean VLBI Network, the Green Bank Observatory and the Very Long Baseline Array (VLBA). The VLBA is a facility of the National Science Foundation under cooperative agreement by Associated Universities, Inc. The data were correlated at the DiFX correlator of the MPIfR in Bonn, Germany. This work made use of the Swinburne University of Technology software correlator (Deller et al. 2011), developed as part of the Australian Major National Research Facilities Programme and operated under licence.With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709.Peer reviewedIOP PublishingEuropean Research CouncilEuropean CommissionNational Science Foundation (US)Gordon and Betty Moore FoundationUniversidad Nacional Autónoma de MéxicoConsejo Nacional de Ciencia y Tecnología (México)Ministerio de Economía y Competitividad (España)Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]202120212021info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Postprintinfo:eu-repo/semantics/acceptedVersionhttp://hdl.handle.net/10261/256621reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Inglés#PLACEHOLDER_PARENT_METADATA_VALUE##PLACEHOLDER_PARENT_METADATA_VALUE#info:eu-repo/grantAgreement/EC/H2020/610058info:eu-repo/grantAgreement/MINECO/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/SEV-2017-0709http://dx.doi.org/10.3847/1538-4357/ac00b0Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/2566212026-05-22T06:33:51Z
score	15,812429

Persistent Non-Gaussian Structure in the Image of Sagittarius A∗ at 86 GHz

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