Millimeter Light Curves of Sagittarius A* Observed during the 2017 Event Horizon Telescope Campaign
Journal article, 2022

The Event Horizon Telescope (EHT) observed the compact radio source, Sagittarius A* (Sgr A*), in the Galactic Center on 2017 April 5-11 in the 1.3 mm wavelength band. At the same time, interferometric array data from the Atacama Large Millimeter/submillimeter Array and the Submillimeter Array were collected, providing Sgr A* light curves simultaneous with the EHT observations. These data sets, complementing the EHT very long baseline interferometry, are characterized by a cadence and signal-to-noise ratio previously unattainable for Sgr A* at millimeter wavelengths, and they allow for the investigation of source variability on timescales as short as a minute. While most of the light curves correspond to a low variability state of Sgr A*, the April 11 observations follow an X-ray flare and exhibit strongly enhanced variability. All of the light curves are consistent with a red-noise process, with a power spectral density (PSD) slope measured to be between -2 and -3 on timescales between 1 minute and several hours. Our results indicate a steepening of the PSD slope for timescales shorter than 0.3 hr. The spectral energy distribution is flat at 220 GHz, and there are no time lags between the 213 and 229 GHz frequency bands, suggesting low optical depth for the event horizon scale source. We characterize Sgr A*'s variability, highlighting the different behavior observed just after the X-ray flare, and use Gaussian process modeling to extract a decorrelation timescale and a PSD slope. We also investigate the systematic calibration uncertainties by analyzing data from independent data reduction pipelines.

Author

Maciek Wielgus

Max Planck Society

Nicola Marchili

Max Planck Society

Istituto nazionale di astrofisica (INAF)

Ivan Marti-Vidal

Universitat de Valencia

Garrett K. Keating

Harvard-Smithsonian Center for Astrophysics

Venkatessh Ramakrishnan

University of Turku

University of Concepcion

Aalto University

Paul Tiede

Harvard-Smithsonian Center for Astrophysics

Harvard University

Ed Fomalont

National Radio Astronomy Observatory

Sara Issaoun

Harvard-Smithsonian Center for Astrophysics

Joseph Neilsen

Villanova University

Michael A. Nowak

Washington University in St. Louis

Lindy Blackburn

Harvard-Smithsonian Center for Astrophysics

Harvard University

Charles F. Gammie

University of Illinois

Ciriaco Goddi

Istituto nazionale di astrofisica (INAF)

University of Cagliari

Daryl Haggard

McGill University

Daeyoung Lee

University of Illinois

Monika Moscibrodzka

Radboud University

Alexandra J. Tetarenko

Texas Tech University at Lubbock

Geoffrey C. Bower

Academia Sinica

University of Hawaii

Chi-kwan Chan

University of Arizona

Koushik Chatterjee

Harvard-Smithsonian Center for Astrophysics

Harvard University

Paul M. Chesler

Harvard University

Jason Dexter

University of Colorado at Boulder

Sheperd S. Doeleman

Harvard University

Harvard-Smithsonian Center for Astrophysics

Boris Georgiev

University of Waterloo

Perimeter Institute for Theoretical Physics

Mark Gurwell

Harvard-Smithsonian Center for Astrophysics

Michael D. Johnson

Harvard University

Harvard-Smithsonian Center for Astrophysics

Daniel P. Marrone

University of Arizona

Alejandro Mus

Universitat de Valencia

Dimitrios Psaltis

University of Arizona

Bart Ripperda

Flatiron Institute

Princeton University

Gunther Witzel

Max Planck Society

Kazunori Akiyama

Harvard University

National Astronomical Observatory of Japan

Massachusetts Institute of Technology (MIT)

Antxon Alberdi

Spanish National Research Council (CSIC)

Walter Alef

Max Planck Society

Juan Carlos Algaba

University of Malaya

Richard Anantua

Harvard-Smithsonian Center for Astrophysics

Harvard University

University of Texas at San Antonio

Keiichi Asada

Academia Sinica

Rebecca Azulay

Max Planck Society

Universitat de Valencia

Uwe Bach

Max Planck Society

Anne-Kathrin Baczko

Max Planck Society

David Ball

University of Arizona

Mislav Balokovic

Yale University

John Barrett

Massachusetts Institute of Technology (MIT)

Michi Baubock

University of Illinois

Bradford A. Benson

University of Chicago

Fermi National Accelerator Laboratory

Dan Bintley

East Asian Observatory

James Clerk Maxwell Telescope

Raymond Blundell

Harvard-Smithsonian Center for Astrophysics

Wilfred Boland

Nederlandse Onderzoekschool voor Astronomie (NOVA)

Katherine L. Bouman

California Institute of Technology (Caltech)

Hope Boyce

McGill University

Michael Bremer

Institut de Radioastronomie Millimétrique (IRAM)

Christiaan D. Brinkerink

Radboud University

Roger Brissenden

Harvard University

Harvard-Smithsonian Center for Astrophysics

Silke Britzen

Max Planck Society

Avery E. Broderick

University of Waterloo

Perimeter Institute for Theoretical Physics

Dominique Broguiere

Institut de Radioastronomie Millimétrique (IRAM)

Thomas Bronzwaer

Radboud University

Sandra Bustamante

University of Massachusetts

Do-Young Byun

Korea Astronomy and Space Science Institute

University of Science and Technology (UST)

John E. Carlstrom

University of Chicago

Chiara Ceccobello

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

Andrew Chael

Princeton University

Shami Chatterjee

Cornell University

Ming-Tang Chen

Academia Sinica

Yongjun Chen

Chinese Academy of Sciences

Ilje Cho

Spanish National Research Council (CSIC)

Pierre Christian

Fairfield University

Nicholas S. Conroy

Harvard-Smithsonian Center for Astrophysics

University of Illinois

John Conway

Chalmers, Space, Earth and Environment, Onsala Space Observatory

James M. Cordes

Cornell University

Thomas M. Crawford

University of Chicago

Geoffrey B. Crew

Massachusetts Institute of Technology (MIT)

Alejandro Cruz-Osorio

Goethe University Frankfurt

Yuzhu Cui

The Graduate University for Advanced Studies (SOKENDAI)

Shanghai Jiao Tong University

National Astronomical Observatory of Japan

Jordy Davelaar

Columbia University

Flatiron Institute

Radboud University

Mariafelicia De Laurentis

Goethe University Frankfurt

National Institute for Nuclear Physics

University of Naples Federico II

Roger Deane

University of Pretoria

University of Witwatersrand

Rhodes University

Jessica Dempsey

James Clerk Maxwell Telescope

Netherlands Institute for Radio Astronomy (ASTRON)

East Asian Observatory

Gregory Desvignes

Paris Descartes University

Max Planck Society

Vedant Dhruv

University of Illinois

Sergio A. Dzib

Institut de Radioastronomie Millimétrique (IRAM)

Max Planck Society

Ralph P. Eatough

Chinese Academy of Sciences

Max Planck Society

Razieh Emami

Harvard-Smithsonian Center for Astrophysics

Heino Falcke

Radboud University

Joseph Farah

Las Cumbres Observatory Global Telescope Network

University of California at Santa Barbara

Vincent L. Fish

Massachusetts Institute of Technology (MIT)

H. Alyson Ford

University of Arizona

Raquel Fraga-Encinas

Radboud University

William T. Freeman

Google Inc.

Massachusetts Institute of Technology (MIT)

Per Friberg

James Clerk Maxwell Telescope

East Asian Observatory

Christian M. Fromm

Goethe University Frankfurt

University of Würzburg

Max Planck Society

Antonio Fuentes

Spanish National Research Council (CSIC)

Peter Galison

Harvard University

Roberto Garcia

Institut de Radioastronomie Millimétrique (IRAM)

Olivier Gentaz

Institut de Radioastronomie Millimétrique (IRAM)

Roman Gold

University of Southern Denmark

Goethe University Frankfurt

Gomez-Ruiz

National Institute of Astrophysics, Optics and Electronics

National Council for Science and Technology Mexico

Jose L. Gomez

Spanish National Research Council (CSIC)

Minfeng Gu

Chinese Academy of Sciences

Kazuhiro Hada

The Graduate University for Advanced Studies (SOKENDAI)

National Astronomical Observatory of Japan

Kari Haworth

Harvard-Smithsonian Center for Astrophysics

Michael H. Hecht

Massachusetts Institute of Technology (MIT)

Ronald Hesper

University of Groningen

Luis C. Ho

Beijing University of Technology

Paul Ho

James Clerk Maxwell Telescope

Academia Sinica

Mareki Honma

University of Tokyo

National Astronomical Observatory of Japan

The Graduate University for Advanced Studies (SOKENDAI)

Chih-Wei L. Huang

Academia Sinica

Lei Huang

Chinese Academy of Sciences

David H. Hughes

National Institute of Astrophysics, Optics and Electronics

Shiro Ikeda

National Astronomical Observatory of Japan

University of Tokyo

The Graduate University for Advanced Studies (SOKENDAI)

The Institute of Statistical Mathematics

C. M. Violette Impellizzeri

Leiden University

National Radio Astronomy Observatory

Makoto Inoue

Academia Sinica

David J. James

ASTRAVEO

Buell T. Jannuzi

University of Arizona

Michael Janssen

Max Planck Society

Britton Jeter

Academia Sinica

Wu Jiang

Chinese Academy of Sciences

Alejandra Jimenez-Rosales

Radboud University

Svetlana Jorstad

Boston University

Joshi

University of Illinois

Taehyun Jung

University of Science and Technology (UST)

Korea Astronomy and Space Science Institute

Mansour Karami

Perimeter Institute for Theoretical Physics

University of Waterloo

Ramesh Karuppusamy

Max Planck Society

Tomohisa Kawashima

University of Tokyo

Mark Kettenis

Joint Institute for VLBI in Europe (JIVE)

Dong-Jin Kim

Max Planck Society

Jae-Young Kim

Max Planck Society

Kyungpook National University

Korea Astronomy and Space Science Institute

Jongsoo Kim

Korea Astronomy and Space Science Institute

Junhan Kim

California Institute of Technology (Caltech)

University of Arizona

Motoki Kino

National Astronomical Observatory of Japan

Kogakuin University of Technology and Engineering

Jun Yi Koay

Academia Sinica

Prashant Kocherlakota

Goethe University Frankfurt

Yutaro Kofuji

University of Tokyo

National Astronomical Observatory of Japan

Patrick M. Koch

Academia Sinica

Shoko Koyama

Academia Sinica

Niigata University

Carsten Kramer

Institut de Radioastronomie Millimétrique (IRAM)

Michael Kramer

Max Planck Society

Thomas P. Krichbaum

Max Planck Society

Cheng-Yu Kuo

Academia Sinica

National Sun Yat-Sen University

Noemi La Bella

Radboud University

Tod R. Lauer

National Optical Astronomy Observatory

Sang-Sung Lee

Korea Astronomy and Space Science Institute

Po Kin Leung

Chinese University of Hong Kong

Aviad Levis

California Institute of Technology (Caltech)

Zhiyuan Li

Nanjing University

Rocco Lico

Istituto nazionale di astrofisica (INAF)

Spanish National Research Council (CSIC)

Max Planck Society

Greg Lindahl

Harvard-Smithsonian Center for Astrophysics

Michael Lindqvist

Chalmers, Space, Earth and Environment, Onsala Space Observatory

Mikhail Lisakov

Max Planck Society

Jun Liu

Max Planck Society

Kuo Liu

Max Planck Society

Elisabetta Liuzzo

Istituto nazionale di astrofisica (INAF)

Wen-Ping Lo

National Taiwan University

Academia Sinica

Andrei P. Lobanov

Max Planck Society

Laurent Loinard

Universidad Nacional Autónoma de México

Colin Lonsdale

Massachusetts Institute of Technology (MIT)

Ru-Sen Lu

Chinese Academy of Sciences

James Clerk Maxwell Telescope

Max Planck Society

East Asian Observatory

Jirong Mao

Chinese Academy of Sciences

James Clerk Maxwell Telescope

East Asian Observatory

Sera Markoff

University of Amsterdam

Alan P. Marscher

Boston University

Satoki Matsushita

Academia Sinica

Lynn D. Matthews

Massachusetts Institute of Technology (MIT)

Lia Medeiros

University of Arizona

Institute for Advanced Study

Karl M. Menten

Max Planck Society

Daniel Michalik

University of Chicago

European Space Research and Technology Centre (ESA ESTEC)

Izumi Mizuno

East Asian Observatory

James Clerk Maxwell Telescope

Yosuke Mizuno

Goethe University Frankfurt

Shanghai Jiao Tong University

James M. Moran

Harvard-Smithsonian Center for Astrophysics

Harvard University

Kotaro Moriyama

Goethe University Frankfurt

Massachusetts Institute of Technology (MIT)

National Astronomical Observatory of Japan

Cornelia Mueller

Radboud University

Max Planck Society

Gibwa Musoke

Radboud University

Chinese Academy of Sciences

Ioannis Myserlis

Institut de Radioastronomie Millimétrique (IRAM)

Andrew Nadolski

University of Illinois

Hiroshi Nagai

The Graduate University for Advanced Studies (SOKENDAI)

National Astronomical Observatory of Japan

Neil M. Nagar

University of Concepcion

Masanori Nakamura

National Institute of Technology, Hachinohe College

Academia Sinica

Ramesh Narayan

Harvard-Smithsonian Center for Astrophysics

Harvard University

Gopal Narayanan

University of Massachusetts

Iniyan Natarajan

University of Witwatersrand

South African Radio Astronomy Observatory (SARAO)

Antonios Nathanail

Goethe University Frankfurt

National and Kapodistrian University of Athens

Santiago Navarro Fuentes

Institut de Radioastronomie Millimétrique (IRAM)

Roberto Neri

Institut de Radioastronomie Millimétrique (IRAM)

Chunchong Ni

University of Waterloo

Perimeter Institute for Theoretical Physics

Aristeidis Noutsos

Max Planck Society

Junghwan Oh

Sejong University

Hiroki Okino

University of Tokyo

National Astronomical Observatory of Japan

Hector Olivares

Radboud University

Gisela N. Ortiz-Leon

Universidad Nacional Autónoma de México

Tomoaki Oyama

National Astronomical Observatory of Japan

Feryal Ozel

University of Arizona

Daniel C. M. Palumbo

Harvard University

Harvard-Smithsonian Center for Astrophysics

Georgios Filippos Paraschos

Max Planck Society

Jongho Park

Academia Sinica

Harriet Parsons

James Clerk Maxwell Telescope

East Asian Observatory

Nimesh Patel

Harvard-Smithsonian Center for Astrophysics

Ue-Li Pen

Canadian Institute for Advanced Research

Academia Sinica

University of Toronto

Perimeter Institute for Theoretical Physics

Dominic W. Pesce

Harvard University

Harvard-Smithsonian Center for Astrophysics

Vincent Pietu

Institut de Radioastronomie Millimétrique (IRAM)

Richard Plambeck

University of California at Berkeley

Aleksandar PopStefanija

University of Massachusetts

Oliver Porth

Chinese Academy of Sciences

Goethe University Frankfurt

Felix M. Potzl

Max Planck Society

University College Cork

Ben Prather

University of Illinois

Jorge A. Preciado-Lopez

Perimeter Institute for Theoretical Physics

Hung-Yi Pu

Academia Sinica

National Taiwan Normal University

Ramprasad Rao

Academia Sinica

Mark G. Rawlings

East Asian Observatory

NSF's National Optical-Infrared Astronomy Research Laboratory (NOIRLab)

James Clerk Maxwell Telescope

Alexander W. Raymond

Harvard University

Harvard-Smithsonian Center for Astrophysics

Luciano Rezzolla

Goethe University Frankfurt

Trinity College Dublin

Frankfurt Institute for Advanced Studies

Angelo Ricarte

Harvard-Smithsonian Center for Astrophysics

Harvard University

Freek Roelofs

Radboud University

Harvard-Smithsonian Center for Astrophysics

Harvard University

Alan Rogers

Massachusetts Institute of Technology (MIT)

Eduardo Ros

Max Planck Society

Cristina Romero-Canizales

Academia Sinica

Arash Roshanineshat

University of Arizona

Helge Rottmann

Max Planck Society

Alan L. Roy

Max Planck Society

Ignacio Ruiz

Institut de Radioastronomie Millimétrique (IRAM)

Chet Ruszczyk

Massachusetts Institute of Technology (MIT)

Kazi L. J. Rygl

Istituto nazionale di astrofisica (INAF)

Salvador Sanchez

Institut de Radioastronomie Millimétrique (IRAM)

David Sanchez-Arguelles

National Council for Science and Technology Mexico

National Institute of Astrophysics, Optics and Electronics

Miguel Sanchez-Portal

Institut de Radioastronomie Millimétrique (IRAM)

Mahito Sasada

Hiroshima University

National Astronomical Observatory of Japan

Kaushik Satapathy

University of Arizona

Tuomas Savolainen

Aalto University

Max Planck Society

F. Peter Schloerb

University of Massachusetts

Karl-Friedrich Schuster

Institut de Radioastronomie Millimétrique (IRAM)

Lijing Shao

Beijing University of Technology

Max Planck Society

Zhiqiang Shen

East Asian Observatory

Chinese Academy of Sciences

James Clerk Maxwell Telescope

Des Small

Joint Institute for VLBI in Europe (JIVE)

Bong Won Sohn

Korea Astronomy and Space Science Institute

University of Science and Technology (UST)

James Clerk Maxwell Telescope

Yonsei University

East Asian Observatory

Jason SooHoo

Massachusetts Institute of Technology (MIT)

Kamal Souccar

University of Massachusetts

He Sun

California Institute of Technology (Caltech)

Fumie Tazaki

National Astronomical Observatory of Japan

Remo P. J. Tilanus

Netherlands Organisation for Scientific Research (NWO)

University of Arizona

Leiden University

Radboud University

Michael Titus

Massachusetts Institute of Technology (MIT)

Pablo Torne

Max Planck Society

Shanghai Jiao Tong University

Efthalia Traianou

Spanish National Research Council (CSIC)

Max Planck Society

Tyler Trent

University of Arizona

Sascha Trippe

Seoul National University

James Clerk Maxwell Telescope

East Asian Observatory

Ilse van Bemmel

Joint Institute for VLBI in Europe (JIVE)

Huib Jan van Langevelde

Joint Institute for VLBI in Europe (JIVE)

Leiden University

University of New Mexico

Daniel R. van Rossum

Radboud University

Jesse Vos

Radboud University

Jan Wagner

Max Planck Society

Derek Ward-Thompson

University of Central Lancashire

John Wardle

Brandeis University

Jonathan Weintroub

Harvard University

Harvard-Smithsonian Center for Astrophysics

Norbert Wex

Max Planck Society

Robert Wharton

Max Planck Society

Kaj Wiik

University of Turku

Michael F. Wondrak

Radboud University

George N. Wong

University of Amsterdam

University College London (UCL)

Qingwen Wu

Huazhong University of Science and Technology

James Clerk Maxwell Telescope

East Asian Observatory

Paul Yamaguchi

Harvard-Smithsonian Center for Astrophysics

Doosoo Yoon

Chinese Academy of Sciences

Andre Young

Radboud University

Ken Young

Harvard-Smithsonian Center for Astrophysics

Ziri Younsi

Princeton University

Goethe University Frankfurt

Feng Yuan

James Clerk Maxwell Telescope

East Asian Observatory

Chinese Academy of Sciences

Ye-Fei Yuan

James Clerk Maxwell Telescope

East Asian Observatory

University of Science and Technology of China

J. Anton Zensus

Max Planck Society

Shuo Zhang

Bard College

Guang-Yao Zhao

Spanish National Research Council (CSIC)

Shan-Shan Zhao

Chinese Academy of Sciences

Astrophysical Journal Letters

2041-8205 (ISSN) 2041-8213 (eISSN)

Vol. 930 2 L19

Subject Categories (SSIF 2011)

Astronomy, Astrophysics and Cosmology

Atom and Molecular Physics and Optics

Other Physics Topics

DOI

10.3847/2041-8213/ac6428

More information

Latest update

3/24/2025