Near-infrared flares from accreting gas around the supermassive black hole at the Galactic Centre

Abstract

Recent measurements of stellar orbits provide compelling evidence that the compact radio source Sagittarius A* at the Galactic Centre is a 3.6-million-solar-mass black hole. Sgr A* is remarkably faint in all wavebands other than the radio region, however, which challenges current theories of matter accretion and radiation surrounding black holes. The black hole's rotation rate is not known, and therefore neither is the structure of space-time around it.Here we report high-resolution infrared observations of Sgr A* that reveal 'quiescent' emission and several flares. The infrared emission originates from within a few milliarcseconds of the black hole, and traces very energetic electrons or moderately hot gas within the innermost accretion region. Two flares exhibit a 17-minute quasi-periodic variability. If the periodicity arises from relativistic modulation of orbiting gas, the emission must come from just outside the event horizon, and the black hole must be rotating at about half of the maximum possible rate.

arXiv comment5 pages, 3 figures to appear in the Oct 30 issue of Nature

References in corpus (22)

• Closest Star Seen Orbiting the Supermassive Black Hole at the Centre of the Milky Way
• Chandra X-ray Spectroscopic Imaging of Sgr A* and the Central Parsec of the Galaxy
• The First Measurement of Spectral Lines in a Short-Period Star Bound to the Galaxy's Central Black Hole: A Paradox of Youth
• Nonthermal Electrons in Radiatively Inefficient Accretion Flow Models of Sagittarius A*
• Rapid X-ray flaring from the direction of the supermassive black hole at the Galactic Centre
• The Supermassive Black Hole at the Galactic Center
• Magnetically Driven Accretion Flows in the Kerr Metric I: Models and Overall Structure
• A Geometric Determination of the Distance to the Galactic Center
• Variable Infrared Emission from the Supermassive Black Hole at the Center of the Milky Way
• A Jet-ADAF model for Sgr A*
• The Nature of the 10 Kilosecond X-ray Flare in Sgr A*
• XMM-Newton observation of the brightest X-ray flare detected so far from SgrA*
• Variability of Sagittarius A* - Flares at 1 Millimeter
• The 67 Hz Feature in the Black Hole Candidate GRS 1915+105 as a Possible ``Diskoseismic'' Mode
• Proper Motion of the Compact, Nonthermal Radio Source in the Galactic Center, Sagittarius a*
• Structure of Sagittarius A* at 86 GHz using VLBI Closure Quantities
• X-ray flares from Sgr A*: star-disk interactions?
• Limits on the Short Term Variability of Sagittarius A* in the Near-Infrared
• Near-Infrared Microlensing of Stars by the Super-Massive Black Hole in the Galactic Center
• Quasi-Periodic Oscillation in Seyfert galaxies: Significance levels. The Case of Mrk 766
• New Constraints on the Nature of Radio Emission in Sagittarius A*
• Measuring the Black Hole Spin in Sgr A*

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• Spherical Accretion in Nearby Weakly Active Galaxies
• Effects of Hydrogen vs. Helium on Electromagnetic Black Hole Observables
• First VLTI infrared spectro-interferometry on GCIRS 7 - Characterizing the prime reference source for Galactic center observations at highest angular resolution
• The Physics of E x B-Drifting Jets
• On the Resolution of the Time-Like Singularities in Reissner-Nordstrom and Negative-Mass Schwarzschild
• Detection of pulsar beams deflected by the black hole in Sgr A*: effects of black hole spin
• Forward Ray Tracing and Hot Spots in Kerr Spacetime
• The X-ray footprint of the CircumNuclear Disk
• Correlation between Flux and Spectral Index during Flares in Sagittarius A*
• Tidal effects in the motion of gas clouds around boson stars
• A Milliarcsecond-accurate Position for Sagittarius A*
• Probing the Spacetime Around Supermassive Black Holes with Ejected Plasma Blobs
• Oscillating axion bubbles as alternative to supermassive black holes at galactic centers
• Theory of disk accretion onto supermassive black holes
• Approaching the event horizon: 1.3mm VLBI of SgrA*
• A new line element derived from the variable rest mass in gravitational field
• Introduction to Non-Baryonic Dark Matter
• An independent hybrid imaging of Sgr A* from the data in EHT 2017 observations
• Adaptive Optics: Observations and Prospects for Studies of Active Galactic Nuclei
• The Effects of Tilt on the Time Variability of Millimeter and Infrared Emission from Sagittarius A*
• Flare emission from Sagittarius A*
• Predictions of the pseudo-complex theory of Gravity for EHT observations: I. Observational tests
• Long-Term Radio Modulation in Sagittarius A* from Spin-Induced Disk Precession
• Accurate closed-form trajectories of light around a Kerr black hole using asymptotic approximants
• General Relativistic effects and the NIR variability of Sgr A* II: A systematic approach to temporal asymmetry
• The impact of resistivity on the variability of black hole accretion flows
• Probing the formation of planetesimals in the Galactic Centre using Sgr A* flares
• Observability of pulsar beam bending by the Sgr~A* black hole
• Possible evidence from the flaring activity of Sgr A* for a star at a distance of ~3.3 Schwarzscild radii from the blackhole
• High-(Energy)-Lights -- The Very High Energy Gamma-Ray Sky
• Low angular momentum flow model of Sgr A* activity
• Magnetic neutral points and electric lines of force in strong gravity of a rotating black hole
• Time delays between radio and X-ray and between narrow radio bands of Sgr A* flares in the shock oscillation model
• New Evidence for a Flux-independent Spectral Index of Sgr A* in the Near-infrared
• Effect of matter geometry on low angular momentum black hole accretion in the Kerr metric
• Predictions of the pseudo-complex theory of Gravity for EHT observations- II. Theory and predictions
• Photons from Dark Matter in a (non-Universal) Extra Dimension model
• Observational signatures from higher-order images of moving hotspots in accretion disks
• Sgr A* as probe of the theory of supermassive compact objects without event horizon
• Study of the Science Capabilities of PRIMA in the Galactic Center
• Coordinated mm/sub-mm observations of Sagittarius A* in May 2007
• A cool disk in the Galactic Center?
• Signatures of Einstein-Maxwell dilaton-axion gravity from the observed quasi-periodic oscillations in black holes
• Monitoring the Size and Flux Density of Sgr A* during the Active State in 2019 with East Asian VLBI Network
• Impact of intrinsic polarisation of Sgr A* historical flares on (polarisation) properties of their X-ray echoes
• Test particles in relativistic resistive magnetohydrodynamics
• A Pacemaker with P=2.48 hour Modulated the Generator of Flares in the X-ray Light Curve of Sgr A* in the year 2012
• The complete exterior spacetime of spherical Brans-Dicke stars
• The orbit and nature of the semi-detached stellar companion of Sgr A* super-massive blackhole
• Constraining the rotating Simpson-Visser spacetime from the observed quasi-periodic oscillations in black holes
• General relativistic formulas for mass and spin of a Kerr black hole in terms of redshifts and orbital parameters
• Global resistive MHD accretion flows around spinning AGNs: impact of resistivity on MAD state
• A kinetic model of jet-corona coupling in accreting black holes
• High Energy Activity of the Super-Massive Black Hole at the Galactic Center
• Area Invariance of Apparent Horizons under Arbitrary Boosts
• Low angular momentum accretion flow model of Sgr A* activity
• The Jet in the Galactic Center: An Ideal Laboratory for Magnetohydrodynamics and General Relativity
• Non-thermal Synchrotron Emission and Polarization Signatures during Black Hole Flux Eruptions
• The X-ray variation of M81* resolved by Chandra and NuSTAR
• Stability of planetary systems within the S-star cluster: the Solar system analogues
• A feasibility study of future observations with MIDI and other VLTI science instruments: The example of the Galactic Center
• The Galactic Center
• Effect of nonlinear electrodynamics on polarization distribution around black hole
• Auto- and cross-correlations for multiple images of corotating hotspots in accretion disks
• Photometric Constraints on Intermediate-mass Black Holes in the Galactic Centre
• Flares from spiral waves by lensing and time-delay amplification?
• News from the year 2006 Galactic Center workshop
• Extended orbital resonance model with hump-induced oscillations
• The Galactic Center with Roman
• Polarimetric Imaging of Sgr A* in its Flaring State
• Deciphering signatures of Kerr-Sen black holes in presence of plasma from the Event Horizon Telescope data
• SgrA* emission at 7mm: variability and periodicity
• Visible shapes of black holes M87* and SgrA*
• Tidal Capture by a Black Hole and Flares in Galactic Centres
• Detecting Flaring Structures in Sagittarius A* with (Sub)Millimeter VLBI
• Variability of Sagittarius A* at 3 GHz on minute-scale with MeerKAT
• HOLESOM: Constraining the Properties of Slowly-Accreting Massive Black Holes with Self-Organizing Maps
• Detection of Gravitational Wave Emission by Supermassive Black Hole Binaries Through Tidal Disruption Flares
• Full-polarization millimeter wavelength variability of Sagittarius A* during the 2018 EHT campaign
• Radio properties of the quasi-periodic eruption source RXJ1301.9+2747 at parsec scales
• High Energy Emission from the Galactic Center
• Numerical methods for General Relativistic particles
• Search for long-term variability of HESS J1745-290
• Sagittarius A* near-infrared flares polarization as a probe of space-time I: Non-rotating exotic compact objects